摘要:

STUDIES ON OPTICALLY ACTIVE CARBIMIDES. PART 11. 93 XI.-Studies on Optically Act iae Carbimides. Part II. The Reactions between LMenthylcarh- imide and A1 co ho Is. By ROBERT HOWSON PICKARD, WILLIAM OSWALD LITTLEBURY, A.I.C., and ALLEN NEVILLE, B.Sc. I-MENTHYLCARBIMIDE reacts fairly readily with alcohols, and the result- ing I-menthylcarbamates are prepared in the manner already described in Part I (Trans., 1904,85, G85). These esters are stable substances, which boil under reduced pressure without decomposition, and are easily soluble in the common organic media. Comparing the com- pounds prepared from the alcohols of the paraffin series, it will be seen that as the molecular weight increases, the melting point and the volatility in steam of the esters decrease. The rotation of these I-menthylcarbamates exhibits a striking regu- larity.The molecular rotation of these esters in solution has an approximately constant value for each solvent independent of the nature of the alcohol from which the ester is prepared. Thus, in chloroform, the molecular rotations of these esters approximate to 160°, in benzene to 140°, and in pyridine to 175'. It may be pointed out that there are several isolated exceptions to these values among the molecular rotations of the fourteen esters investigated, but every ester has the approximate value for the molecular rotation in a t least one of the three solvents. The reaction between I-menthylcarbimide and ethyl alcohol has been studied in detail and is easily followed by polarimetric observations. It is a bimolecular reaction, the velocity being proportional to the con- centration of the two reacting substances.I f the reaction is carried out in ethyl-alcoholic solution, the alcohol concentration remains con- stant throughout the reaction, and the velocity is dependent only on the concentration of the carbimide and proportional to it. The reaction i n this case may be considered as being unimolecular. If, however, the reaction is carried out in a neutral solvent where the concentration of the alcohol is comparable with that of the carbimide, the velocity is dependent on the two concentrations, both of which vary throughout the range of the reaction, which in this case is bimolecular. The velocity constant of this reaction varies greatly with the nature of the solvent employed. It is noteworthy how the tertiary amines accelerate the velocity of the reaction.Primary and secondary amines cannot be used as solvents, since they react with I-menthyl- carbimid e.94 PICKARD, LITTLERURY, AND NEVILLE: STUDIES ON Nitrobenzene ................. 8 -9 Toluene ........................... 1 -2 Xyleiie (from commercial “ xylol”) ........................ 0.9OPTICALLY ACTlVE CARBIMIDES. PART 11. 95 In the following table, our results are compared with those of Menschutkin ; in each case the value for ethyl alcohol has been put at 100 for the purpose of comparison : I Velocity constants of alcohols with With I-menthyl- acetic Alcohol. cnrbimide. anhydride. Methyl .. 106'3 206% Ethyl ...... 100*0 100.0 I Propyl.. ... 90.5 88% 1 n-Butyl __ 81'3 85.9 n-Octyl ...49'4 69.6 Cetyl ...... 56.1 49.5 j n-Heptyl ... 58 .S 72'5 Velocity constants of alcohols with With I-menthyl- acetic Alcohol. cnrbimide. anhydride. isoButyl ..... 65'7 74 -1 Ally1 ......... 83 '4 53'5 Beiizyl ......... 54 '8 51'6 Phenylethyl.. 10 '4 - Phenylpropyl 50.5 - Ciiiiiamyl ... 485' - isoPropyl ...... 68.4 27 *3 The most striking difference in these two series of results is with methyl alcohol. As is generally found in comparing the members of the paraffin series, the first member differs somewhat markedly from those following in its physical and often in some of its chemical pro- perties. Thus, Menschutkin finds that the velocity constant of the reaction between methyl alcohol and acetic anhydride is nearly double that of the reaction between ethyl alcohol and the anhydride, whilst we find that the velocity constant of the reaction between methyl alcohol and I-menfhylcarbimide is only slightly greater than that between ethyl alcohol and the carbimide.The differences between the two series of results are to be ascribed not only to the influence of hydro- carbon radicles on the reactivity of the alcohols, but also, of course, to the use of the two specific reagents, acetic anhydride in the one series and I-menthylcarbimide in the other. The comparative regu- larity of both series of results serves to emphasise the irregular influence of alkyl groups on the reactions of alkyl iodides, the knowledge of which has been extended and summarised by Donnan (Trans., 1904, 85, 555).Esters of 1-Menthylcnrbamic Acid, C,,H,,*NH-CO2R The esters of I-menthylcarbamic acid are readily prepared (as described in Part I, Eoc. c i t . ) by heating molecular proportions of the respective alcohols with I-menthylcarbimide. They are easily purified by distillation either with steam or under reduced pressure. They possess a pleasant, characteristic odour, and are soluble in the common organic media except where otherwise stated. Methyl E&ei*.-The melting point of this compound is 6 3 O , not 53' as printed in Part I. The n-butyl ester is volatile with steaw and solidifies ih clusters of colourless, stellate needles which melt a t 37".96 PICKARD, LITTLEBURY, AND NEVILLE : STUDIES ON 0.2266 gave 11.4 C.C. moist nitrogen a t 16" and 756 mm. C,,H,90,N requires N = 5.51 per cent.The n-heptyl ester was obtained as a pale yellow, refractive oil, which boiled at 215'/82 mm.; when cooled to the temperature of a mixture of ice and salt, it slowly crgstallised in long needles, which melted indefinitely at 22-25'. It is only very slowly volatilised by steam. N = 5 9 0.3337 gave 15.3 C.C. moist nitrogen at 24" and 758 mm. N = 5.1. C,,H,,O,N requires N = 4.71 per cent. The n-octyl ester is a pale yellow liquid which boils at 220°/24 mm. ; it is very viscous, strongly refractive, and not volatile with steam. 0.3764 gave 16.8 C.C. moist nitrogen at 2%' and 754 mm. N = 5.0. ClgH,702N requires N = 450 per cent. The cetyl ester is only slightly soluble in light petroleum,from which it crystallises in colourless needles; these melt a t 53.5" and are not volatile with steam. 0.3050 gave 9.1 C.C.moist nitrogen at 15" and 752 mm. N = 3.4. C27H,80,N requires N = 3.31 per cent. The allyl ester, after distillation with steam, solidifies in pearly, colourless plates which melt a t 40". 0.3010 gave 16.6 C.C. moist nitrogen a t 15" and 737 mm. N = 6.2. Cl,H,,02N requires N = 5-86 per cent. The isopropyl ester solidifies, after distillation with steam, in white, lustrous plates which melt at 70". 0,2502 gave 13.0 C.C. moist nitrogen at 15' and 750 mm. N = 6.0. C,,H,702N requires N = 5-81 per cent. The isobutyl ester solidifies, after distillation with steam, in masses of colourless, stellate needles which melt at 38-40'. 0.2942 gave 15.2 C.C. moist nitrogen at 26' and 758 mm. N = 5.7. C15H2,0,N requires N = 5.49 per cent.The benzyl ester is a pale yellow, refractive, viscous oil, which boils 0.3408 gave 15.3 C.C. moist nitrogen a t 22' and 754 mm. The phenylethyl ester is a pale yellow, refractive, viscous oil, which at 235"/25 mm. and is not volatile with steam, N=5.0. Cl,H270,N requires N = 4-84 per cent. boils at 240°/25 mm. and is not volatile with steam.OPTICALLY ACTIVE CARBIMIDES. PART 11. 97 0.3800 gave 15.8 C.C. moist nitrogen at 23' and '752 mm. N = 4.6. C,gH,,O,N requires N = 4.62 per cent. The cirznamyl ester crystallises from petroleum (b. p. 120-1 30') in white needles which melt at 68-70'. 0.2250 gave 9.3 C.C. moist nitrogen a t 1 8 O and 739 mm. N = 4.6. Cj20H2902N requires N = 4-41 per cent. The phenylpropyl ester crystallises from light petroleum in white, 0.2511 gave 10.5 C.C.moist nitrogen a t 17' and 740 mm. N=4-7. lustrous plates which melt a t 64'. C,,H,,O,N requires N = 4.41 per cent. Rotations oj* the 1-Menthylcarbamates. The following rotations were made in a 2-dcm. tube (unless other wise stated) at the temperature of the laboratory. Preliminary experiments showed that a small variation in temperature between 18' and 25' or a variation in the concentration of the solution from 2 to 20 parts per 100 of solution made practically no difference in the values obtained for the specific rotations. Rotations in Chloroform. Ester. Methyl* ........ Ethyl* ......... Propyl.. .......... n-Heptyl.. ....... Cetyl ........... isoPropyl ...... Benzyl.. .......... Phenylethyl ... Cinnamyl ......Phenylpropyl ... n-Butyl ......... n-Octyl ......... -Ally1 ............ isoButyl ...... Weight in grams. 1.5720 1-5351 0.5889 0.9066 1.3556 1.8214 09754 1 -6045 0.3849 0'3678 1-5113 0.9328 0.8846 0.8568 Vol. of solution in C.C. 20'0 20.0 25'0 20'0 20.0 20.0 20.0 20.0 19.7 19.9 20.0 20.0 20 -0 25 .O Observed rotation. - 12.21" - 11'05 -3'23 - 5.88 - 7'48 - 9-49 - 3'60 - 10.95 - 2-57 - 2 '45 - 7.98 - 5-23 - 4.39 - 1-65 f- La],. - 77 '67" - 71'98 - 68-66 - 64'85 - 55-18 - 52.10 - 36.90 - 68.24 - 65.77 - 66-28 - 52.80 - 56'06 - 49.62 - 48.14 * The specific rotations of these esters are somewhat higher than 1. Observation made in a 1-dcm. tube. Part I. [ M I D . 165.5 163.4 165.2 165.4 168.9 162.0 156-1 163.1 158.5 169.0 152-6 169'8 756.3 152.6 given in VOL. LXXXIX.H98 PICKARD, LITTLEBURY, AND NEVILLE: STUDIES ON Rotrrt ions in Benzene. Weight in Ester. grams. Methyl.. .......... 1.0707 Ethyl ............ 1.1146 Propyl ............ 1'3438 n-Heptyl ......... 0.9028 Cetyl ............ 1'0809 Allyl ............ 1-2383 isoPropy1.. ....... 0 *7840 is0 Butyl ......... 0 *2 8 94 Benzyl ............ 1 '1 062 Phenylethyl ... 1.1949 Cinnamyl ...... 0.2309 n-Butyl ......... 0'5780 n-OCtyl ......... 1.4140 Vol. of solution in C.C. 20.0 20'1 20 '0 19'8 20.0 20 '0 24.7 19.8 20.0 19.9 19'9 19'8 19.9 0 bserved rotation. - 6'83" - 6.61 - 7.73 - 3'14 - 4'42 - 6-56 - 2'89 - 7 '29 - 4 '39 - 1'56 - 5-54 - 6 '53 - 1'09 Rotations in, Pyridine. Weight in Ester. grams. Methyl ............ 0.9727 Ethyl ............ 1.5185 n- Butyl ......... 0'4181 n-Octyl .........1'5317 Yropyl ............ 1 *1863 n-Heptyl ......... 0.8628 Cetyl ............ 2*0119 Allyl ........... 0.5002 isol'ropyl ......... 0.4507 Kenzyl ............ 1.3892 Cinnamyl ...... 0 *9757 isonuty1 ......... 0 -9349 Phenylethyl ... 0.5713 Phenylpropyl ... 1.3542 Vol. of solution in C . C . 19.7 19'9 19.9 19.9 20 *o 20.0 19 '9 20.0 20.0 19.7 19.9 20 *o 20.1 25 *o Observed rotation. - 8 *OO" - 11-53 - 8'59 - 2.94 -5.75 - 8.70 - 4'12 - 3'74 - 3 '23 - 6 *59 - 8.64 - 3 *84 - 5.76 -3.15 * - 63-79' - 59'60 - 57.52 - 53.91 - 48'96 - 46-38 - 33.02 - 58.28 - 55.99 - 53-63 - 49'83 - 54'10 -46'97 [.ID. - 81.01" - 7555 - 72-05 - 69 '96 - 59'69 - 56'80 - 40'51 - 74.77 -71.66 - 69'43 - 61 '88 - 67 *21 - 59.33 - 58.15 l?flD. 135.9 135.3 138.6 137.5 145.4 143.3 139.7 134.9 136.8 144.0 163.9 147'9 A39 *3 172.5 1.71.5 173% l i 8 .4 177.3 176.7 171'4 178.7 172.7 177.0 178% 203 -6 186-8 184.3 * Observation made in a l-dcm. tube, Reaction between Ethyl Alcohol and l-MenthyZcar6imide. That the velocity of the reaction beheen ethyl alcohol and Z-menthylcarbimide is proportional not only to the carbimide concen- tration, but also to the alcohol concentration,is shown by the deter- mination of the velocity-constants recorded in Tables I and 11. The experiments recorded in Tables I and 111 to XI were performed with equivalent quantities in order to determine the influence of the solvent on the velocity of the reaction, and the " K " values have been calculated from the formula KA =-.- . To obtain further confirmation of the result recorded in Table I, the reaction mas carried out with twice the equivalent quantity of 1 x t a-xOPTICALLY ACTIVE CARBIMIDES.PART 11. 99 alcohol (Table II), and the velocity-constant calculated according t o the formula for a bimolecular reaction with non-equivalent quantities : where C, is the excess of one reagent over the other, that is, in this case one equivalent or equal to the concentration of the carbimide. The " K " value thus obtained and recorded in Table I1 is in fair accordance with the '' K" value obtained with equivalent quantities recorded in Table I. The ethyl alcohol used in the experiments detailed in this paper had been heated with silver oxide in a reflux apparatus and then dried over barium oxide until a crystal of potassium permanganate pro- duced only a very faint coloration.The other solvents were carefully dried and had constant boiling points. The method which has been employed to determine all the velocity- constants recorded in this paper (with the exception of those in the section on the influence of temperature) is as follows : an accurately weighed quantity of the carbimide (about 2 grams) is mixed in a graduated flask (20 to 25 c.c.) with the solvent and the calculated quantity of the alcohol. After the rotation has been observed in the polarimeter, the flask is placed in a thermostat a t 50°. At intervals, the flask is withdrawn, quickly cooled to the laboratory temperature, and the rotation again observed. Throughout the paper, the times are expressed in hours, and the concentrations ( A ) in gram-molecules per litre.The infinity values are in some cases the results of actual observations, and in others are calculated from the specific rotation of ethyl l-menthylcarbamate in the various solvents. Both methods when compared gave identical values. TABLE I.-h Toluene. I TABLE II.-In Toluene. Time. 0 18.25 25-16 90 '84 97.66 121'00 138.83 144'40 m Rotation. 9'06 9-28 9.33 9 *80 9-84 9-95 10.03 10.08 11.26 Mean KA= 0.00565. K= 0.0124. A = 0 '455. KA. 0'00548 0 '00558 0.00558 0'00562 0.00561 0 '00 568 0'00598 - - Time. 0 71.1 78.2 95.5 101 *6 119.4 125-4 m Rotation. 9'01 10'29 10.35 10-54 10.56 10.67 10.70 11'59 KY cm x0-431% - 0.00244 0-00240 0 *00248 0.00239 0.00234 0*00231 - Mean = 0 *00239. C , =0'462. K= 0 '01 19.100 PJCKARD, LITTLEBURY, AND NEVILLE : STUDIES ON TABLE III.-In Chloroform.Time. 0 22.00 27.41 45.58 99.83 117.83 a3 Rotation. KA. 8 *71 - 10.36 0'0146 10-69 0.0151 11.55 0.0158 12.85 0'0158 13.30 0-0178 15'48 - Mean X A = 0'0158. K= 0.0324. A= 0.487. TABLE IV.-Ifi Curbon Taka- chloride. Time. i 7-66 5-60 23.42 1 30.33 1 47'50 ~ 53.92 a3 Rotation. KA. 8'10 - 8'26 0.0392 8 *56 0.0387 9'36 0.0895 9.56 0.0415 9 '81 0.0396 9-90 0.0407 10'72 - Mean K A = 0.0398. K= 0,0902. A = 0'442. TABLE V.-In Pyridine. 1 TABLE VI.-Ifi Tripropylurnine. Time. 0 1 *80 2.50 4-64 5 '40 6 '08 7.15 00 Rotation. 8.98 9.69 9'92 10'44 10'66 10.79 11-01 1326 Mean K A = 0.117. A = 0.386. K= 0.302. A second experiment with gave K= 0'301. KA . 0.111 0.113 0.112 0.120 0.121 0.126 - - A=0'497 TABLE VII.ZN Benzene. Time. 0 1.33 5.50 25.08 29.66 49.16 55.99 Rotation. KA. 9.21 - 9'26 0 -0244 9.40 0.0246 9'80 0.0235 9-89 0'0251 10.07 0.0240 10.12 0.0239 10.80 - Mean KA = 0'0242. K- 0.0540. A = 0'449. Time. 0 0'33 1-08 2-58 4'91 9'66 24.16 00 Rotation. KA. 9-58 - 9 -80 0.447 10.14 0.451 10.50 0'451 10.76 0'453 10.97 0,450 11.15 0.464 11-29 - Mean KA = 0'453. A = 0.452. K= 1 *OO. 1 TABLE VIII.-In XyZerrze.* Time. 0 19-75 43-08 67.75 91-67 116.08 163.89 188'09 236.10 00 Rotation. 9-50 9-80 10.1 3 10'42 10-62 10.77 11'11 11.30 11 *53 13'69 KA. 0.00390 0-00410 0.00415 0.00398 0'00375 0'00381 0'00400 0.00398 - - Mean KA = 0.00396. K= 0.00870. A=0*451. * Commercial "xylol" which had been dried and fractionated ; it boiled at 140".OPTICALLY ACTIVE CARBIMXDES.PART IT. 101 TABLE IX.-In Acetone. Time. 0 1.58 19-66 25.91 43.25 50.08 67.16 00 Rotation. K A . 9 '42 - 9'51 0-0138 10.25 0'0125 10.53 0.0138 11-06 0'0148 11'08 0.0130 11 '53 0.0150 13'62 - Mean KA=O-O138. K=0'0295. A = 0.467. Time. 10.75 73.75 80.50 0 00 TABLE X.-h Nitro6enxene. Time. Rotation. KA. 0 9-30 - 2.83 9'57 0.0416 21'66 10.47 0.0388 69-82 11 -22 0'0429 94.16 11.35 0.0429 rn 11.86 - Mean K A =0.0415. K = 0 '0937. A = 0'443. TABLE XI.-In Chlorobenxene. Rotation. KA. 10.40 - 10.64 0'00759 13.04 0'00748 13'13 0-00754 13'58 - Mean KA = 0.00753. A=0'451. K= 0.0167. The reaction between ethyl alcohol and the carbimide in dimethyl- aniline solution under the conditions of the above experiments pro- ceeds too rapidly for readings in the polarimeter to be observed.InJuence of Ternpei*ature on the Rate of Reuction between Ethyl Alcohol and 1-Mertthylcarbimide. The velocity constants recorded in this section were determined in a jacketed polarimeter tube round which circulated water previously passed through a long copper coil immersed in a thermostat kept at the required temperature. These experiments were carried out in ethyl-alcoholic solution and the concentration of the carbimide varied from 0.50 to 0.15, preliminary experiments having proved that t h i s variation did not affect the results. The temperatures at which the observations were made were read on a standard thermometer immersed in the reaction mixture. The maximum variation in temperature was less than 0.25". The '' K" values are calculated from the formula K= l/tlog.C,/C, and the infinity values from the specific rotations of ethyl Z-menthyl- carbamate in ethyl-alcoholic solution at the various temperatures.102 PICKARD, LITTLEBURY, AND NEVILLE : STUDIES ON TABLE X1I.-At 244 Time. 0 6 -08 18-16 23.50 28'08 34-05 03 Rotation. K. 2-92 - 3.23 0.0135 3-77 0.0152 3 '90 0'0141 4'01 0.0143 4'13 0.0141 4.72 - Mean K= 0.0142. A second experiment made a t 24.5" gave K= 0'0143. TABLE XIV.-At 39'. Time. 0 2 *25 3'25 4'33 5 -75 7.91 9.75 03 Rotation. K. 4-36 - 4'92 0-0489 5'11 0.0476 5 -29 0-0466 5 *55 0'0488 5.85 0'0497 6 *06 0.0507 6-86 - Mean K = 0'0470. Tinie. 0 0.50 1-58 2-75 4-66 6'16 18-25 03 TABLE XII1.-At 319 Time. 0 2.93 3'58 4'56 5'00 5-66 6.16 6.75 9.33 10.25 11 *33 12.00 03 Rotation . 10-44 11.36 11 '64 11.83 12.04 12.22 12.35 12.46 13.01 13'13 13.29 13.37 15'90 Mean k'=0'0290. K.0-0274 0'0300 0.0279 0.0301 0.0302 0.0303 0-0297 0.0296 0'0287 0'0282 0.0278 - - TABLE XV.-At 43O. Time. 0 1 '00 2'00 3'08 4'16 5'33 6'15 10'83 oc) Rotation, 9.01 9'56 10.03 10.40 10.86 11 '23 11.43 12.37 13'79 Mean K=0'0506. TABLE XV1.-At 50'. Rotation. K. 4'57 - 5'03 0.0678 5.33 0'0688 5-63 0.0697 5.97 0.0677 6.15 0-0647 6'84 0-0680 7.00 - Mean K= 0.0674. K. 0.0531 0.0521 0.0484 0-0510 0.0509 0.0498 0'0486 - - Rate of Reaction between l-Menthylcarbimide and Various AZcohoZs. The rates of reaction between Z-menthylcarbimide and various alcohols have been measured in pyridine solution. The alcohols, which, with the exception of the phenylpropyl alcohol, were all obtained from Kahlbaum, had constant boiling points and were inactive.The phenylpropyl alcohol, which was prepared from Kahlbaum's cinnamyl alcohol, had a constant boiling point and did not decolorise bromine. The maximum difference in the '' K" values obtained when the determinations were repeated was under 10 per cent.OPTICALLY ACTIVE CARBIMIDES. PART 11. 103 TABLE XV11.- With MethgZ A Zcoho I . Time. 0 1.16 1 *84 2-40 3-00 3 '50 4.40 5 .oo 5'66 6.56 m Rotation. 10.11 10.76 11.05 11.32 11.56 11.64 11 9 6 12.15 12'32 12.65 14-94 Mean KA = 0.143. A = 0.446. K = 0 320. KA . 0.134 0.132 0'139 0'143 0'132 0.141 0 146 0.149 0.1 69 _. -- TABLE XIX.-With n-ButyZ Alcohol. Time. 0 0.58 1.21 1'88 3'08 4.75 5-91 7.08 11.30 00 Rotation. 9.54 9.85 10.15 10'48 10.88 11 '45 11.77 12.11 12-82 15-35 Mean KA=0.1041.A = 0.4304. K = 0.242. KA . 0.0972 0.0969 0.1063 0,0973 0.1031 0'1054 0.1120 0'1147 - - TABLE XXI.-TVitith n-0ctyZ Alcohol. Time. 0 1-55 2-25 3'00 4'33 5'55 6.76 8.38 00 Rotation. 13-83 14-81 15.17 15.59 16-15 16'63 16.97 17'34 21'88 Mean K A =10'0925. K= 0.149. A =0*619. KA. 0 '0894 0-0887 0.0933 0,0935 0'0961 0'0946 0'0922 - - [ TABLE XVIIL- JVith n-Propgl A Zcoh o I. I Time. 0 1.16 1-88 3.08 4.50 5'32 6.32 8 -88 24.40 00 Rotation. 7-99 l * i 4 7'94 8 *19 8.44 s '61 8.70 9.14 10.01 11.19 Mean KA = 0.0885. K= 0.275. r - d = O 321. KA . 0.0874 0.0900 0'0866 0.0848 0'0889 0'0832 0'0961 0.0910 - - TABLE XX.-lVith n-Neptpl A Zcoho 1.' Time. 0 1'16 1'66 2.16 3.25 4-16 5'00 5.83 6-91 00 Rotation. 10.85 11.43 11-65 11.80 12.14 12.45 12-72 12-99 13.14 17.03 Xll.0.0892 0.0856 0'0841 0'0812 0.0839 0.0868 0'0908 0'0852 - - Mean KA =0.0863. k'= 0'179. Other values obtained were K= 0.171 and 0.182. A =0*480. TABLE XXI1.- Tlrii% Cetyl Alcohol. Time. X o tation. KA. 1 '92 10.75 0.0802 3.00 11-05 0.0773 11.25 0-0774 4 $0 11.35 0'0714 5 '33 11.57 0.0742 6'33 11.85 0'0794 25'75 13'62 0'0748 m 15'49 - 10'02 - Mean l i A = 0-0764. K-OW9. A = 0.452.104 STUDIES ON OPTICALLY ACTIVE CARBIMIDES. PART 11. TABLE XXIIL- With Ally? Alcohol. Time. Rotation. KA. 0 7.34 - 1 *25 7-68 0.0751 1 '88 7-83 0.0751 2-50 7-99 0.0785 3 -00 8 *07 0'0753 3'83 8 *27 0.0801 4'40 8-38 0.0809 5.06 8-48 0.0808 25.24 10.02 0.0829 00 11-30 - Mean KA =0*0786. K= 0.249, A=0.316. TABLE XXV.- With isoButyZ Alcohol. Time, 0 1'50 2'41 4'41 5'16 6.66 7'41 9.25 og Rotation. 8'88 9-36 9.59 10.09 10.24 10'51 10.65 10'94 13-72 Mean KA =0*0756.A =0.387. KA. 0'0734 0.0711 0'0755 0.0756 0'0762 0.0777 0-0801 - I TABLE XX1V.- With isoPropyZ A Zcoho I. Time. 0 0'60 1 *46 2 *28 5-28 6.95 CL) Rotation. KA. 12-56 - 12-93 0.105 13'44 0'112 13-83 0.112 14-96 0.119 15.30 0'113 18.80 - Mean KA = 0.112. A = 0.544. K = 0 -206. TABLE XXVL- With Benzyl A Zcoho I. Time. Rotation. KA. 0 11-39 - 0-83 11.87 0.0924 1'66 12'15 0.0766 2-41 12-51 0.0827 0'0822 3'91 13 *03 4 -75 13.29 0.0827 5'66 13'56 0.0839 6.83 13'84 0.0836 8 '40 14'22 0-0862 co 18-13 -. Mean KA = 0.0838. A=0*507. K=0'195. A second experiment gave K = 0.202. K = 0'165. TABLE XXVIL- With Phenylethyl A1 coho I . Time. 0 0 -63 1 -95 4 -61 6-00 7-50 9'00 10.50 00 Rotation. 10.50 10-58 10.74 11'04 11'19 11.37 11'52 11-67 19'14 Mean KA = 0.0147. K= o-os12. A = 0 '47 0. KA. 0'0148 0'0146 0.0145 0.0145 0.0149 0.0149 0'0149 - - TABLE Time. 0 1-00 1'83 2-66 3-66 4'50 5-33 6-50 9-17 10.75 11.92 aJ XXV1II.- Vith Phernyl- propyl Alcohol. Rotation. 10.81 11.25 11-55 11-89 12.11 12'38 12-63 12'95 13'48 13.75 13'79 17-38 Mean KA = 0-0718. K= 0.162. A=0'531. KA . 0.0718 0.0694 0'0739 0.0674 0-0698 0.0719 0.0743 0.0746 0.0753 0.0696 - -SUDBOROUGH AND JAMES : a-CHLOROCINNAM[C ACIDS. 105 TABLE XXJX.-Fith Cinnamyl A Zcohol. Time. Rotation. KA. 0 12-08 - 0.70 12-46 0'0724 1'46 12-87 0.0763 2.36 13.33 0.0799 3 '00 13'53 0'0752 4-58 14'14 0.0773 Time. Rotation. KA. 5.41 14'43 0.0785 6-16 14-69 0.0804 7-00 14'93 0.0813 8.55 16-31 0.0812 00 19.96 - Mean K A =0.0781. K = 0'147. A=0'531. We desire to express our thanks to Mr. H. L. Leech for valuable assistance in some of the preparative and analytical work for this paper and also to the Research Fund Committee of the Chemical Society for a grant defraying much of the cost of this work. MUNICIPAL TECHNICAL SCHOOL, BLACKBURN.

ISSN:0368-1645    

DOI:10.1039/CT9068900093

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

SUDBOROUGH AND JAMES : a-CHLOROCINNAM"2 ACIDS. 105 XI I. -a - Chloro cinnumic A cid s. Eg JOHN JOSEPH SUDBOROUGH and THOMAS CAMPBELL JAMES. IN previous communications (Sudborough and Thompson, Trans,, 1903, 83, 666 and 1154), attention has been drawn to the action of various alkalis on cinnamic acid dibromide and its esters. By means of the reactions :-olefinic acid + bromine - hydrogen bromide, it is usual to obtain the bromo-derivative of an acid stereoisomeric with the original acid. Our previous results have shown that with cin- namic acid itself this is largely true, the final product being mainly a-bromoallocinnamic acid, but that when the acid is replaced by one of its esters the product obtained by the elimination of hydrogen bromide is a mixture of a-bromocinnamic and a-bromoallocinnamic acids, the a-bromo-acid, however, preponderating. I n this paper, we give anaccount of similar experiments which have been made with cinnamic acid dichloride (up-dichloro-P-phen ylpropionic acid) and its esters. The results indicate that the reaction with the chloro-acid is quite different from that with the dibromide, as the product obtained was always a mixture of a-chloro- and a-chloroallo- cinnamic acids, the a-chloro-acid predominating. The yields of the two acids are affected to only a slight extent by altering the alkali or the temperature, or even by substituting the methyl or ethyl ester for the acid dichloride.Experiments in which organic bases were employed in place of potassium hydroxide did not give satisfactory results.106 SUDBOROUGH AND JAMES : a-CHLOROCINNAMIC ACIDS.The reaction bet ween cinnamic acid dichloride and alcoholic potash has been previously studied by Tutz (Ber., 1882, 15, 788), Michael and Pendleton (J. pr. Chem., 1889, [ii], 40, 65), and Mulliken (Dis- sertation, Leipxig, 1890). All obtained a mixture of two chloro-acids, which were separated by taking advantage of the considerable differ- ence in solubility of their potassium salts in absolute alcohol. The acid melting a t 136-137' was termed a-chlorocinnamic acid by Michael and Pendleton, and the acid melting a t 1 10-1 11' a-chloro- allocinnamic acid. The numbers given by Mulliken (Zoc. cit.) indicate that the two acids are Formed in almost equal quantities; thus from 5 grams of cinnamic acid dichloride the following weights of potassium salts were obtained in different experiments :- Experiment. 1.2. 3. 4. 5. 6 . 7. a-Chloro- ...... 2'64 2.63 2'30 2'31 2'48 2.51 2.29 grains a-ChloroaZEo- ... 2.26 2'29 2.55 2.47 2'38 2-37 2.52 ,, Michael and Pendleton, on the other hand, state t h a t the amount of a-chloroallo-acid is always much less than that of the a-chloro-acid. These same chemists also show t h a t the acid synthesised by Plochl (Ber., 1882, 15, 1945) from benzaldehyde, sodium chloroacetate, and acetic anhydride is identical with the acid melting a t 136-137', and thus the a-position of the chlorine in the latter is established. As the acid meltiug at 110' is readily transformed into this acid, it also presumably contains the chlorine atom in the a-position.This is all the more probable siuce Michael and Pendleton have prepared two stereoisomeric P-chlorocinnamic acids by the addition of hydrogen chloride t o plienylpropiolic acid. I. Preparation, of up-Dichloro-P-phenylpropionic Acid and its Esters. Very good yields of cinnamic acid dichloride can be obtained by passing chlorine for several hours into EL suspension of finely-divided cinnamic acid in five times its weight of dry carbon disulphide (Erlenmeyer, Ber., 1881, 14, 1867 ; Mulliken, Zoc. cit.). I n our different experiments, we have obtained 134, 138, 127, 140, 120,133, and 140 grams from 100 grams of cinnarnic acid by removing the crystals and washing with a little carbon disulphide. We have attempted to chlorinate methyl cinnamate in a similar manner and also in chloroform solution, but the yields were poor.Good yields of methyl cirmamate dichloride may be obtained by esterifying cinnamic acid dichloride by Fischer and Speyer's method (Ber., 1895,28, 3252). 'l'he quantities we used were one of acid to two of pure methyl alcohol containing 4 per cent. of hydrogen chloride, and the mixture wasSUDBOROUGH AND JAMES : a-CHLOROCINNAMIC ACIDS. 107 boiled for two hours. When cold, a considerable quantity of the ester had separated. This was removed, more hydrogen chloride passed into the filtrate, and the solution again heated for two hours. We obtained on an average a 92 per cent. yield of ester melting a t 101' (Finkenbeiner, Ber., 1894, 27, 890). Ethyl cinnamate dichloride has been prepared by Finkenbeiner (Zoc.c i t . ) , who describes it as an oil. We have prepared the same ester by the Fischer-Speyer method from cinnamic acid dichloride. After pouring into water, extracting with ether, and shaking out the ethereal solution with dilute sodium carbonate solution, we dried the solution with calcium chloride and removed the ether. The oil which was left (yield, 92 per cent.) solidified to a crystalline mass melting at 30'. It is readily soluble in all organic solvents, and crystallises from light petroleum in well-developed, colourless prisms melting a t 30-31'. 11. Separation of a-ChZoro- and a-Chloroallo-cinncmic Acids. As the method adopted by Michael (J. pr. Chem., 1889, [iii], 40, 63) and Mulliken (Zoc. cit.) for separating the acids by means of the different solubilities of the two potassium salts in alcohol was somewhat tedious, we attempted the separation by meansof the barium salts,as described in the separation of a-bromo- and a-bromocdlo-cinnamic acids (Trans., 1903, 83, 673), and the results proved that complete separation is readily effected by this method, although loss of acid, especially of the allo-scid, occurs.Expt. 1.-Two grams of each acid, when mixed and separated as the barium salts, gave 1.80 grams of aZlo-acid melting at 110-11lo and 1-91 grams of a-chloro-acid melting at 136'. Expt. 2.-Two grams of each acid gave 1.80 grams of aZEo- and 1.92 grams of a-chloro-acid melting a t 13'7'. The losses in these experiments are rather larger than with the corresponding bromo-acids (Zoc. cit.). 111. Action of Alkalis on Cinnamic Acid Dichloride and its Esters. We have made a number of experiments on the action of alkalis on the dichloride and its esters, using the same general method as described in the case of the bromo-derivatives (Zoc.cit., p. 674), with the object of determining the influence of the following factors : (a) tem- perature, (6) the alkali, (c) replacing the acid by its esters, ( d ) solvent. The results we have obtained are given in the following table. The numbers given in each case are the mean of mveral experiments.108 SUDBOROUGH AND JAMES : a-CHLOROCINNAMIC ACIDS. TABLE I. Cinnarnic Acid Dichlo~ide, 10 grams. Alkali. Alcoholic potassium hydroxide . . , Aqueous potassium hydroxide, N. 9 , 7 3 $ 9 ... 9 9 ... 9 9 9 , 9 9 9 ) ... ... f ) J Y I > 99 ...... Aqueous sodium hydroxide ......... Sodium ethoxide ..................... Y , ), ..................... Alcoholic sodium hydroxide ...... Aqueous potassium hydroxide, 3 N 3 ) 2 ) 3 1 3 4.52 4-70 4.82 6 '35 5.75 5.25 4.32 4'0 5-86 4'62 4'46 5 *77 6.0 5 *35 2.88 2.75 2'83 1-27 1.80 2-14 1-35 0.87 1.71 2'84 2-85 1'82 1'68 1'88 7'40 7 '45 7-65 7'62 7-55 7-28 5 '67 4-87 7 *57 7 '46 7.31 7.59 7-68 7-25 Conditions. Standing overnight a t 0". Ordinary temperature. Boiling for 10 minutes. Standing overnight a t 0". 15". Ordinary temperature in At 50-60" for 6 hours. On boiling water-bath for Ordinary temperature. Boiling for 15 minutes. Overnight a t ordinary 15". 15". 15". July. 40 minutes. temperature. Heti$ Cinnamate Dichloride, 10.64 grams. Alcoholic potassium hydroxide ...1 6'64 I 1.30 1 7-94 1 Both a t 0" and on boiling. Ethgl Cinnanaate Dichloride, 1 1.28 grams. Alcoholic potassium hydroxide ... 1 6'49 1 1-40 1 7.89 1 Both a t 0" and on boiling. The theoretical amount of mixed a-chloro-acids is 8.33 grams. The conclusions to be drawn from these experiments are : (1) The alkali used evidently affects the relative amounts of the two acids formed. Aqueous potassium hydroxide gives a better yield of the a-chloro-acid than does alcoholic potash, as do also aqueous and alcoholic sodium hydroxide. (2) The temperatiire factor is small and, in the case of aqueous potassium hydroxide, tends slightly t o increase the relative yield of allo-acid and, a t the same time, to form neutral products. At the higher temperatures, chlorocinnamene is undoubtedly formed and may be recognised by its odour.(3) The effect of alteration of concentration is slight.SUDBOROUGH AND JAMES : a-CHLOROCINNAMlC ACIDS. 109 (4) The substitution of an ester for the cinnamic acid dichloride has not the same marked effect as with the dibromide. The yield of a-chloro-acid is increased somewhat and that of the aZZo-acid corre- spondingly decreased. ( 5 ) It will be noticed that in all the experiments the yield of a-chloro-acid is much greater than the yield of a-bromo-acid from the dibromide and its esters under similar conditions (Zoc. cit., p. 680). The action of the tertiary amines, dimethylaniline, and quinoline on cinnamic acid dichloride has also been studied. Ten grams of the dichloride were boiled on the water-bath for four hours with the requisite amount of dimetbylaniline (2 mols.) in methyl-alcoholic solution.The alcohol was removed and the residue treated with hydrochloric acid. From the residue, 0-9 gram of a chloro-acid was obtained, melting at 138" after recrystallisation from benzene. This was undoubtedly a-chlorocinnamic acid; the other product was an oil which only slowly solidified. When 10 grams of the acid were boiled in a similar manner for two hours with a methyl-alcoholic solution of quinoline, the products were 6.3 grams of unchanged acid dichloride and a small amount of oil. When the heating was continued for eight hours, a product was obtained from which were isolated, by means of the barium salts, 3.1 grams of a-chloro-acid melting a t 138' after recrystallisation, 1.5 grams of unaltered dichloride melting at 164', and 1 gram of neutral oil.IV. Transformation of a- Chloroallocinnwnic Acid into its Isomeride. ( a ) Influence of Light. Expt. 1.-Two grams of powdered solid a-chloro-acid were exposed to bright sunlight from July to November, 1904. The melting point a t the end of this time was still 137", indicating that no change had occurred. Expt. 2.-Two grams of a-chlorocdlocinnamic acid were exposed under exactly similar conditions, and the melting point fell from 11 1' to 90'. The exposed acid was separated into a-chloro- and a-chloro- aZZo-acids by means of the barium salts, and gave 1.1 grams of unaltered allo-acid melting a t 108" and 0.65 gram of a-chloro-acid melting at 136O. The melting point was 90-9Bo, and the product gave 0.9 gram of a-chloro- acid melting at 137' and only 0.65 gram of unaltered do-acid melting at 11 lo.Zxpt. 4.-Some light petroleum mother liquors obtained from crystallising a-chloroallocinnamic acid were exposed to bright sunlight during four summer months, and gave a considerable quantity of well- developed prisms of the a-chloro-acid melting a t 1374 Expt. 3.-Similar to 2, but exposed from June to August.110 SUDBOROUGH AND JAMES : a-CHLOROClNNBMIC ACIDS. Expt. S.--Two grams of a-chloroallocinnamic acid were dissolved in benzene and allowed to remain for three months in an open tube in ordinary daylight. As the benzene evaporated, crystals were deposited. These melted at 11 1' and proved t o be unchanged a-chloroallo-acid. ( b ) InJuence of Terrtpercbtui.e,-The following series of experiments shows the effect of heating small quantities of the a-chloroallo-acid a t a temperature of 155' for the stated periods.TABLE 11. Weight of Weight of a-allo-acid. Time in hours. a-chloro-acid. 11. p. 2.0 grams 0'5 0*081 i37--13a0 2.0 ) > 2.0 ) ) 3'0 0 '320 138 1 '0 0'132 137-1 38 These numbers, compared with those obtained for the conversion of a-bromoallocinnamic acid into a-bromocinnamic acid (loc. cit., p. 687), indicate that the transformation of the a-chloroallo-acid proceeds more slowly than that of the a-bromodlo-acid a t the same temperature. V. Elinainution of Hydrogen Chloride and Hydrogen Bromide from thc a-Chloro- and a-Bromo-cinnamic Acids. Experiments have been made by heating given weights of the respective acids with known volumes of standard potassium hydroxide solution (2 mols.) for given periods of time in a boiling water-bath and titrating the excess of alkali with standard oxalic acid, using phenolphthalein as indicator.TABLE 111. a-Bromocinnamic Acid.-In each experiment 1,244 grams of acid were When dissolved in 54.41 C.C. of 0.201 5 AT-potassium hydroxide. t = 0, the number of C.C. of oxalic acid required = A = 27.40. Time in hours. A - X . 2. l/Lz/A( A - 2). 1-0 11'4 16.00 0.0512 1-5 9'0 18 '40 0.0497 1-75 8 '4 19-00 0 0472 3.0 6 '4 21 '00 0.0399 Mean = 0.0473. Calcnlated for N-potassium hydroxide = 1 *16.SUDBOROUGH AND JAMES : a-CHLOROCINNAMIC ACIDS. 1 I1 TABLE I V . a-Chlorocinnamic Acid.-In each experiment, 1 gram was dissolved in 54.41 C.C.of 0.201 5 N-potassium hydroxide. A = 27.4. Time in hours. A - z. X. l/tx/A(A - x). 4 24.0 3-40 0 *0001297 7 22-4 5.00 0.0001 164 8 21.7 5'70 0.0001 198 9 20'8 6'60 0 '0001286 Mean = 0-001236. Calculated for N-potassium hydroxide = 0.0309. TABLE V. a-Chlorocinnumic Acid.-In each experiment, 1 grain of the acid was The number of dissolved in 10.96 C.C. of N-potassium hydroxide. C.C. of oxalic acid required when t = O was 5*48=A. Time in hours. A -x. X. l / t x / A ( A - x). 1 4-6 0.88 0.0350 2 3.81 1 '67 0'0399 4 3.07 2-41 0.0358 6 2'42 3.06 0.0384 Rlenii = 0.0373. TABLE VI. a-Bromoallocinnamic A ciJ.-Similar t o experiments in Table V, except t h a t 1.244 grams of acid were used in each experiment. A = 5.48. Time in hours.A - 2. X. l/dz/A(A - x). 1 4.94 0 '54 0.0199 2 4 '37 1.11 0.0230 4 3'90 1 5 8 0.0185 6 3-15 2.33 0.0225 Mean = 0.0210. TABLE VII. a-Chloroallocinnamic Acid.-Same as for experiments in Table V. A = 5.48. Time in hours. A - x. X. l/tx/A(A - r). 6.0 4.75 0.73 0'00468 8 '0 4-50 0 -98 0-00496 10.5 4 '41 1-07 0.00422 24'0 * 4.16 - - 24.0 * 4.32 I - * I n these experiments, there was a strong odour of chlorocinnamene.112 SUDBOROUQH AND JAMES : a-CHLOROCINNAMIC ACIDS. TABLE VIII. The constants of the four acids calculated for normal solutions are : K. K. 1-16 a-Bromocinnamic . . . . . . a-Chlorocinnamic . . . ... 0.0373 and 0.0309 a-ChloroalZocinnamic . . . . . . . . . 0.00462 These numbers clearly show that the hydrogen. haloid is eliminated much more readily from the a-acids than from the allo-isomerides, and, further, that hydrogen bromide is eliminated much more readily than hydrogen chloride.The readiness with which hydrogen hsloids are eliminated from the a-halogen acids as compared with the stereoisomerides cannot be used as an argument in favour of the cis-positions of hydrogen and halogen in the a-acids, since it is now known that trans-addition of halogen and trans-elimination of halogen hydracid frequently occur (compare Werner, Stereochemie, p. 225). The relative rates of esterification of the a-acids and their allo-isomerides (compare Sudborough and Lloyd, Trans., 1598, 73, 91 ; Sudborough and Roberts, Trans., 1905, 87, lS40) harmonise best with the view that in the allo-acids the hydrogen and halogen are in the cis-positions.1 a-Bromoallocinnamic ... .. . . .. 0.0210 Ph*g-H C0,HC-X a-allo- Acid. Ph*g.H X*@.CO,H a-Acid. where X=C1 or Br. Preparation of Plberzylpropiolic Acid from Ciiananzic Acid Dicldoride. The numbers given in Table V I I I show that in attempting to prepare phenylpropiolic acid from cinnamic acid dichloride it is advisable to proceed in two stages. The cinnamic acid dichloride is decomposed with aqueous potassium hydroxide a t Oo, or with aqueous sodium hydroxide a t the ordinary temperature, or the methyl ester is decomposed with alcoholic potash. In each case, the a-chloro- and a- chloroallo-acids are separated by means of their barium salts, and the pure a-chloro-acid is then heated with 3.5 mols. of 20 per cent. aqueous potassium hjdroxide for eight hours on the water-bath.The mixture is allowed t o cool-general1 y overnight-and any crystals of potassium a-chlorocinnamate removed. The clear solution is gradually acidified with concentrated hydrochloric acid, and the phenylpropiolic acid which separates as an oil quickly solidifies, and when dry is crystallised from carbon disulphide or from a mixture of chloroform and light petroleum (boiling at SO-90'). Prom 60 grams of a-chlorocinnamic acid, we have obtained 25 gramsSUDROI~OUGH AND JAMES : a-CHLOROCINNAMIC ACIDS. 113 of crude phenylpropiolic acid melting at 1 10-120°, and after crystal- lisation 20 grams of pure acid melting a t 136O, which corresponds with a 42 per cent. yield of pure acid. VI. Derivatives of a-Chlorocinnamic Acids. We have prepared a number of derivatives of the a-chloro- and the a-chloroallo-acid from the acids obtained in the experiments recorded.Methyl a-chlorocinnawmte, C,H,*CH:CCl-CO,Me, is readily obtained by Fischer and Mpeyer's method of esterification, using a 4 per cent. solution of hydrogen chloride in methyl alcohol. It is readily soluble in all organic solvents, even in light petroleum (b. p. 40-50°), and crystallises from the latter in colourless prisms melting at 33-33.5'. The same ester has been prepared by Mulliken (Zoc. cit., p. 27) from the silver salt. a-Chlorocinnamyl chloride, C,H,*CH:CCl*COCl, obtained in the usual manner by the action of phosphorus pentachloride (18 grams) on the acid (15 grams), is a yellow oil with a penetrating odour, and distils at 156' under 22 mm.preesure. During cold weather it sets to a mass of long, flat needles and may be crystallised from light petroleum, in which it is somewhat readily soluble, in the form of long, colourless, flat needles some 2 inches long, melting at 32.5"; 0.6436 gram was gently warmed with an excess of pure potassium bydroxide solution, then acidified with nitric acid, filtered from the a-chlorocinnamic acid when cold, and the filtrate precipitated with silver nitrate. AgCl= 0.4606. C1= 1'7.70. Theory requires 17.64 per cent. When heated with lime, 0.4766 gave 0.6750 AgC1. C,H,OCl, requires 35.29 per cent. a-Chlorocinnamide, C,H,*CH:CC1-CO*NH2, obtained by adding the chloride to concentrated ammonium hydroxide, crystallises from dilute alcohol in long, flat, glistening plates melting at 121-122'; i t also crystallises From benzene in colourless pln tes with a mother-of-pearl lustre.C1= 35.02. 0.4 gave 28.5 C.C. of moist nitrogen at 17' and 763 mm. When distilled with caustic potash, 0.6016 gram evolved ammonia NH,= 8.82. C,H,ONCl requires NH, = 8.82 per cent. The anilide, C,H,=CH:CCl=CO*NH.C,H,, obtained in a similar manner, crystallises from alcohol in compact, eolourless needles melting at 1 1 6-1 1 6 * 5 O . N = 8.3. C,H,ONCI requires N = 7.7 per cent. which neutralised 31.93 C.C. of 0.1039 N sulphuric acid. VOL. LXXXIX. II14 SUDBOROUGH AND JAMES : a-CHLOROCINNAMlC ACIDS. 0.5 gave 24.5 C.C. of moist nitrogen at 18' and 748 mm. Cl,Hl,ONC1 requires N = 5.44 per cent. The p-toluidide, C,H,*CH: CCI*CO*NH*C,H,*CH,, crystallises from alcohol in well-developed, flat prisms or from benzene in snow-white, glistening plates melting at 116'.A mixture of the anilide and p-toluidide begins to melt at 90' and is almost completely molten a t 98O. N = 5.57. 0.5 gave 22.7 C.C. of moist nitrogen a t 1'7' and 760 mm. C16H1,0NCl requires N = 5.16 per cent. The isomeric o-toluidide crystallises from dilute alcohol in compact, colourless prisms, melts at 78O, and is much more readily soluble in most organic solvents than its isomeride. C1= 12.52. N = 5.27. 0.5266 gave 0.2667 AgC1. C,,H1,ONC1 requires C1= 13.06 per cent. The a-naphthalide, C,H,*CH:CC1*CO*NH*C,,H7, crystallises from benzene or alcohol in small, colourless, felted needles melting a t 134'. I n the preparation of the a-naphthslide, the acid chloride does not react with the a-naphthylamine at all readily, but the reaction becomes vigorous when the mixture is heated, 0.5 gave 21.2 C.C.of moist nitrogen at 17' and 754 mm. N = 4.88. C,,H,,ONCl requires N = 4-56 per cent. The P-naphthalide, obtained in a similar manner, crystallises from benzene in compact prisms and from alcohol in flat, glistening plates or in needles melting at 139'. 0.506 gave 0.2343 AgC1. C1= 11-47, Cl9H1,ONCl requires C1= 11 5 3 per cent. Derivutives of a-Chloroallocinnamic Acid.-The chloride was obtained by mixing together chloroform solutions of the do-acid and phosphorus pentachloride, leaving the mixture for twenty-four hours, and then re- moving the chloroform and the oxychloride by distillation under reduced pressure. The chloride itself was not distilled and was obtained as a yellow oil. The amide crystallises from benzene in slender, white needles melting a t 134O. 0.3230, when distilled with potassium hydroxide, evolved ammonia which neutralised 18.62 C.C. of 0.0958 N sulphuric acid. C,H,ONCl requires NH, = 8.82 per cent. NH, = 8.84. The anilide crystallises from dilute alcohol in slender, felted needles and melts at 138-139O.NAPHTIIOYLBENZOIC ACID AND NAPHTHACENEQUINONE. 115 0,5019 gave 0.2735 AgC1. C1= 13.48. C,,H,,ONCl requires C1= 13.77 per cent. The p-toluidide crystallises from dilute alcohol in snow-white, 0.5830 gave 0,3094 AgCI. prismatic needles melting at 132'. C1= 13.12. C,,H,,ONCl requires C1= 13.06 per cent. I n conclusion, we desire to express our thanks to Mr. S. H. Beard for assistance in the preparation and analysis of certain of the compounds and to the Research Fund Committee of the Chemical Society for a grant which has assisted in meeting the expenses in- volved in this investigation. UNIVERSITY COLLEGE OF \VALES, ABERYSTWYTH.

ISSN:0368-1645    

DOI:10.1039/CT9068900105

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年代:1906

数据来源: RSC

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NAPHTFIOYLBENZOIC ACID AND NAPHTHACENEQUINONE. 115 XIJ I.-Some Derivatives o j Xaphthoylbenxoic Acid and of Naphthacenequinone. By JAN QUILLER ORCHARDSON and CEARLES WEIZNANN. H H H H Nc6phthacene, H H H H and n,aphthacenequi?zone, H O H H were first prepared from ethindiphthalide by Gabriel and Leupold (Ber., 1898, 31, 1279)) and subsequently Deichlers and Weizmann (Bey., 1903, 36, 547) obtained (1)-hydroxynaphthacenequinone by the action of sulphuric and boric acids on a mixture of phthalic anhydride and a-naphthol : 1 2116 ORCHARDSON AND WEIZMANN : SOME DERlVATIVES OF By melting phthalic anhydride with a-naphthol and boric acid alone they obtained (1)-hydroxynaphthoylbenzoic acid, and found that this acid is evidently an intermediate product in the formation of (1)-hydroxynaphthacenequinone by the above-mentioned process, since when heated with sulphuric and boric acids it is con- verted into this substance.I n the following experiments, we have sought to make various derivatives of (1)-hydroxynaphthoylbenzoic acid, and with their aid to obtain the corresponding derivatives of naphthacenequinone, this indirect method being necessary on account of the difficulty of obtain- ing pure products by direct substitution in naphthacenequinone itself. We met, however, in the course of the experiments, with greater difficulty than we had anticipated, owing to the facility with which most of the substituent groups are eliminated when the attempt is made t o condense the derivatives of naphthoylbenzoic acid to the corresponding naphthacenequinones by means of concentrated sulphuric acid.During the preparation of (1)-chloronaphthoylbenzoic acid by the action of phosphorus pentachloride on (1)-hydroxynaphthoylbenzoic acid (Proc., 1904, 20, ZZO), we had previously noticed the formation of a red substance insoluble in caustic potash. By a modificat:ion of the experimental conditions this was ultimately obtained as the chief product of the reaction, and we find that it is evidently a monochloro- co naphthacenequinone, C,H,<co>C,oH,C1, and isomeric with that pre- pared by Pickles and Weizmann (Proc., 1904, 20, 220). is converted into phenylaminonaphthacenequinone, The new monochloronaphthacenequinone, when digested with aniline, We next found that (1)-hydroxybromonaphthoylbenzoic acid, UGH4<gE2fZ\C10Hfi <z:i:j ’ was very readily prepared by the action of bromine on (1)-hydroxy- naphthoylbenzoic acid, and the corresponding (1) -hydroxybromonaphth- acenequinone, CGH4<Eg> C,0H4<i:g)), was obtained from this by the action of concentrated sulphuric acid, although considerable decomposition occurred during the reaction.The position of theNAPHTHOYLBENZOIC ACID AND OF NAPHTHACENEQUINONE. 117 bromine is not yet known wit.h certainty, but as the substance does not form an azo-compound with diazobenzene chloride, whereas the (1)-hydroxynaphthoylbenzoic acid does, it is probable that the bromine occupies the position (6) indicated in the above formula. Considerable difficulty was experienced in obtaining a monochloro- but we ultimately obtained a good yield of the acid by treating (1)-hydroxy- bromonaphthoylbenzoic acid with phosphorus pentachloride in the presence of benzene.I n attempting to prepare nitro- and amino-derivatives of naphth- acenequinone, we found that the action of nitric acid on naphthacene- quinone did not give satisfactory results owing to the difficulty of separating the various products of the reaction. Again, (1 )-hydroxy- naphthoylbenzoic acid is decomposed by the action of nitric acid ; we therefore first methylated it, and on treating the methyl ester of the methoxynaphthoylbenzoic acid thus formed with nitric acid, a good yield of the mononitro-compound was obtained, which, on hydrolysis, yielded 1 -hydroxynitronaphthoylbenzoic acid : monobromonaphthoylbenzoic acid, C,H4<C0,H\Cl,H,<~r, co - We were unable to obtain the hydroxynitronaphthacenequinone corresponding to this acid by the action of sulphuric acid, and there- fore proceeded to reduce it with zinc and acetic acid.It was interest- ing to find that by this means, instead of obtaining 1-hydroxyamino- naphthoyl benzoic acid, condensation occurred simultaneously with reduction and yielded 1 -hydroxyaminonaphthacenequinone, Experiments are at present in progress which we hope will clearly demonstrate the positions of the nitro- and amino-groups in the com- pounds mentioned above, and the results of which will be published shortly. EXPERIMENTAL. Mortochloronaphthacenepuinone. I n order to prepare this substance perfectly dry, (1)-hydroxy- naphthoylbenzoic acid (40 grams) was mixed with benzene (200 c.c.) and a considerable excess of phosphorus pentachloride (80 grams) was added gradually in such a way that the reaction was kept well under118 ORCHARDSON AND WEIZMANN : SOME DERIVATIVES OF control.The whole was then heated on the boiling water-bath with a reflux condenser until no further evolution of hydrogen chloride occurred. The benzene was next distilled off over a free flame (not from the water-bath), and when most of the solvent had passed over, a brisk reaction again set in, with further evolution of hydrogen chloride, and the contents of the flask assumed a deep red colour. Water was added to decompose phosphorus oxychloride and pentachloride, the solid was collected at the pump, digested with caustic potash, washed, and dried.It was then recrystallised from nitrobenzene, from which it separated in bright red needles, which retained their colour after repeated crystallisation in presence of animal charcoal. 0.1790 gave 0-4810 CO, and 0.0582 H,O. C = 73.3 ; H = 3.6. C,,H,O,CI requires C = 73.3 ; H = 3.1 ; C1= 12.1 per cent. This monochloronaphthacenequinone melts a t 254O, and is therefore isomeric with the yellow compound obtained by the action of sulphuric acid on 1-chloronaphthoylbenzoic acid (Pickles and Weizmann, Proc., 1904, 20, 220). Phenylacminonaphthacenequinone was obtained from the above chloronaphthacenequinone by boiling it for two hours with just sufficient aniline to dissolve it. On cooling, the substance separ- ated in red leaves melting a t 245'. 0.1698 ,, 0.0768 AgC1.C1= 11.2. 0.1 120 gave 0.3379 CO, and 0.0472 H20. C = 82.2 ; H = 4.7. 0.2108 ,, 7.6 C.C. nitrogen at 18' and 756 mm. N=4.12. C2,H1,02N requires c1= 82.2 ; H = 4.3 ; N = 4.00 per cent. When warmed with sulphuric acid, this phenylaminonaphthacene- quinone yields a strongly fluorescent solution, indicating that condens- ation has taken place with formation of the corresponding acridine derivative, but the latter substance has not yet been obtained in a state sufficiently pure for analysis. (l)-Hydroxybromcmaphthoylbelnzoic Acid and (1)-Hydroxybromo- naphthacenequinone. This acid was readily prepared by slowly adding bromine (40 grams) to (1)-hydroxynaphthoylbenzoic acid (60 grams) suspended in carbon disulphide. When the initial vigorous reaction had subsided, the whole was boiled on the water-bath for four hours and until no further evolution of hydrogen bromide was observed. The carbon disulphide was then distilled off and the residue, which consisted of the almost pure acid, was recrystallised from glacial acetic acid, a small quantity of sodium bisulphite being added to remove free bromine.The new bromo-acid separated in pale yellow crystals melting at 236'.NAPHTHOYLBENZOIC ACID Ah'D OF NAPHTHACENEQUINONE. 119 0.1822 gave 0.3875 CO, and 0.0465 H,O. 0.1'724 ,, 0.0862 AgBr. Br= 21.5. C, *H,BrO, requires C = 5 8.2 ; H = 3.0 ; Br = 2 1 5. (I) -HydroxybrornonnphthoyZbenzoic acid dissolves in sulphuric acid, yielding a brown solution which, on warming, becomes green, then blue, and finally deep red.I f this solution is heated to about 140°, at which temperature bromine begins to be evolved, and is then im- mediately poured into water, a red precipitate is deposited, which consists mainly of (1 )-hydroxybrornonaphthacenequinone. It is collected on a filter, washed with hot sodium carbonate solution, and crystal- lised from nitrobenzene, from which it separates in red needles, which do not melt at 300'. Owing to some elimination of bromine during the preparation, a specimen sufficiently pure to give good results on analysis was not obtained. C=57*9; H=2*8. (1 )-Chlorobromonaphthoylbenxoic Acid and (1 )-Chlorobromonaphthacme- quinone. Twenty grams of (1)-hydroxybromonaphthoylbenzoic acid (see last section) were mixed with a small quantity of benzene, and 23 grams of phosphorus pentachloride were added gradually, the whole being then warmed on the water-bath until no further evolution of hydrogen chloride occurred.The time required for the completion of the reaction was about four hours. Only a small quantity of the solvent and no excess of phosphorus pentachloride should be employed, other- wise a pale yellow, crystalline compound containing phosphorus is obtained, which, owing to its similar appearance and behaviour, is readily mistaken for the chlorobromonaphthoylbenzoic acid. This phosphorus compound gave considerable trouble, and various ex- pedients were tried to avoid its formation, such as varying the solvent used and heating phosphorus pentachloride with hydroxybromonaph- thoylbenzoic acid in the dry state. The former procedure always gave the phosphorus compound, and the latter variously halogenated mix- tures.It was found by using benzene as the solvent and taking special precautions that an excellent yield of the chlorobromo-acid could be obtained. At the end of the reaction, no solid matter should have separated, but the product should be a rather viscid, dark brown oil. Prom this as much benzene is distilled off as possible a t the temperature of the boiling water-bath. The residue is then treated with water and allowed to stand for some hours with frequent shaking, and until the acid chloride is completely decomposed. The white solid which separates is collected on a filter, washed, and recrystallised from glacial acetic acid, from which it separates in almost colourless crystals melting at 180'.120 OHCHARDSON AND WEIZMANN : SOME DERIVATIVES OF 0.2313 gave 0.4666 CO, and 0.0531 H,O.0.2296 ,, 0.1542 AgCl and AgBr. C1= 8.9 ; Br = 20.0. C,8H1,0,U1Br requires C = 55.4 ; H = 2.6 ; C1= 8.7 ; Br = 20.0 per cent. (l)-C'hZorobromonapT~thoylbenxoic acid undergoes similar colour changes to (1)-hydroxybromonaphthoylbenzoic acid when treated with concen- trated sulphuric acid, giving finally a chlorobromonaphthacenequinone, which, however, on account of the occurrence of partial decomposition during the reaction, was not obtained in a sufjiciently pure state for analysis. C = 55.0 ; H = 2.5. Methyl (1 )-Methozyna~hthoyZbenxoccte, ,Wethy I? ( 1 ) - Afethoxy-6-nitro- napTLthoylbenxoate, and (1 )-Hydroxy-6-nitronc~~T~tJ~oyZbenxoic Acid.I n order to prepare the first mentioned of these substances, ( 1)-hydroxynaphthoyl benzoic acid (40 grams) was dissolved in an excess of caustic potash (25 per cent.) containing about 40 grams of this alkali. To this solution, when quite cold, methyl sulphate (30 grams) was added in very small portions at a time with frequent shaking, cooling being resorted to when necessary. A still greater excess of Inethyl sulphate may often be used with advantage, but the solution must always remain alkaline. During the operation, a yellow substance separates out, either in the solid state or as an oil, according to the temperature at which the reaction is carried out. When cold, the solid is collected on a filter, washed, and recrystallised from glacial acetic acid.Methyl (1)-methoxynaphthoylbenzoate separates from acetic acid in colourless, transparent cryst.als, which become opaque on exposure to air and melt a t 110'. 0.2198 gave 0.6038 CO, and 0.1068 H,O. C20H,60, requires C = 75.0 ; H = 5.0 per cent. The yield of this substance varies and a considerable quantity of partially methylated acid remains in the alkaline solution. We have several times attempted to obtain (1)-methoxgnaphthacene- quinone by first partially saponifying the above-described methyl ester with caustic potash, and then acting on the free acid with concentrated sulphuric acid. Complete hydrolysis, however, occurs under these conditions and the product obtained is (1)-hydroxynaphthacene- quinone. ATitration.-The finely-po wdered methyl ( 1 )-rnethoxynaphthoyl- benzoate was treated with nitric acid (sp.gr. 1.42) in the cold, the vigorous reaction being kept under control by immersion in ice when necessary. A small portion of the ester passed into solution, the remainder changing first to a soft, and finally to a brittle mass, which C = 74.9 ; H = 5.3.NAPH'I'HOYLBENZOIC ACID AND OF NAPHTHACENEQUINONE. 121 floated on the surface of the liquid. After diluting with water, the solid matter mas collected, washed well, and recrystallised from glacial acetic acid, from which it separated in bright yellow crystals melting a t 136'. 0.1715 gave 0.4305 CO, and 0.0640 H20. 0.2272 ,, 8.6 C.C. N at IS0 and 762 mm. N=4*37. C = 68.4 ; H= 4.1. C2,Hl,0,N requires C = 68.3 ; H = 4.4 ; N = 3.82 per cent. From the methyl (1 )-~nethoxy-6-nitronaphthoylbenxoate, by boiling for five hours with strong caustic potash and then precipitating with hydro- chloric acid, (1 )-hydroxy-6-nitronaphthoyl6enxoic acid was obtained.It crystallises from glacial acetic acid in slender, lemon-yellow needles. 02126 gave 0.4920 CO, and 0.0460 H20. 0.2310 ,, 8.3 C.C. N at 17' and 762 mm. N = 4-18. C = 63.5 ; H = 3.3. C1,HllO,N requires C = 64.1 ; H = 3.0 ; N = 4.15 per cent. ( 1 )-Hydroxy-6-nitroizc6phthoylben~o~c acid melts at 220' and dissolves in caustic potash, forming a deep orange-red solution. When treated with concentrated sulphuric acid, it does not yield hydroxynitro- naphthacenequinone, because decomposition takes place with evolution of oxides of nitrogen. We next attempted to prepsre (l)-hydroxy-6-aminonaphthoylbenzoic acid by reducing the above-described hydroxynitro-acid, but found that the product of the reaction consisted of (l)-hydroxy-6-amino- naphthacenequinone. The experiment was conducted as follows : (l)-hydroxy-6-nitro- naphthoSlbenzoic acid was dissolved in hot glacial acetic acid, and then zinc dust gradually added in small quantities, when the solution became deep red and finally deposited minute, dark red, glistening crystals. After gently boiling for half an hour, the crystalline precipitate was collected on a filter while hot, washed with acetic acid and water, dried well, and extracted with nitrobenzene, from which solvent deep red crystals, insoluble in sodium carbonate, separated. 0.2131 gave 0.5896 CO, and 0.0847 H20, 0.2495 ,, 10.3 C.C. N at 1 5 O and 762 mm. N=4*9. C1,HI,O,N requires C = 743' ; H = 3.8 ; N = 4.7 per cent. (l)-Hydroxy-6-aminonaphthacenepzcicnone melts above 300O. It dissolves in caustic potash with a deep red colour, and its solution in concentrated sulphuric acid exhibits a beautiful and very strrong green fluorescence. C = 75.4 ; H = 4.40. THE VICTORIA UNIVERSITY OF MANCHESTER.

ISSN:0368-1645    

DOI:10.1039/CT9068900115

出版商:RSC    

年代:1906

数据来源: RSC

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122 WEIZMANN AND FALKNEK. : XI V.-Ethyl $-Nap?ithoylcccetate. By CHARLES WEIZMANN and ERNEST BASIL FALKNER. DURING the course of his researches on ethyl acetoacetate, Claisen (Annnlen, 1896, 291, 67) showed that this reagent may be used with great advantage in the synthesis of other ketonic esters, and i t thus became possible to prepare a considerable number of important com- pounds which were either previously unknown or had only been obtained with difficulty. Ethyl benzoylacetate, for example, is readily prepared by acting on ethyl sodioacetoacetate (2 mols.) with benzoyl chloride (1 mol.) and then decomposing the sodium compound of ethyl benzoylacetoacetate, which is produced by digesting with ammo- nia and ammonium chloride. 2CH,*CO*CHNa*CO,Et + C,H,*COCl= ~ ~ ~ : ~ ~ > C N a * C O , E t + CH,*CO*CH,*CO,Et + NaCl.32::E>UNa-CO2Et + H,O = C,H,*CO*CH,*CO,Et + CH,* C02Na. A t a later date, Needham and Perkin (Trans., 1904, 85, 150) used a similar decomposition, namely, the interaction of o-nitrobenzoyl chloride with ethyl sodioacetoacetate for the preparation of ethyl o-nitrobenzoylacetate. Since the compounds in the naphthalene series corresponding to ethyl benzoylacetate are unknown and should be of considerable value as synthetical agents, we undertook the present research, the object of which was to prepare and investigate ethyl P-aaphthoyl- acetate and some of its derivatives, Pure P-naphthoic acid was converted, by the action of phosphorus pentachloride, into P-naphthoyl chloride, and this was then allowed to react with the sodium derivative of ethyl acetoacetate, when a sparingly soluble sodium derivative was obtained, which on treatment with acid yielded a solid mass of ethyl P-naphthoylacetoacetate, The substance melts at 57", and when digested with ammonia and ammonium chloride is partially hydrolysed with elimination of the acetyl group and formation of ethyl /3-naphthoylacetate, /\/\- CO C Hz CO,E t I l l 2 \/\/ETHYL P-NAPHTHOYLACETATE.123 an interesting substance which melts at 34", gives with ferric chloride a red coloration, is not readily soluble in dilute sodium hydroxide, and in general shows properties similar to those of ethyl benzoylacetate. When treated with phenylhydrazine, it is readily converted into a hydrazone which crystallises in yellow needles, melts at; 95", and probably possesses the formula Preliminary experiments indicate that exactly similar substances are produced when a-naphthoic acid is substituted for the P-acid in the above experiment, and it is proposed to submit both series of substances to a detailed investigation.Ethyl P-Na~l~thoylacetoacetate. /3-Naphthoyl Chloride.-After several experiments, it was found that the following process gives a good yield of this acid chloride. P-Naphthoic acid (35 grams) and phosphorus pentachloride (45 grams) are mixed in small quantities at a time in a distilling flask, which is warmed gently in a water-bath to start the reaction. The decom- position takes place rapidly, and a t the end of half an hour the acid chloride is ready for distillation. After the phosphorus oxychloride had passed over, the P-naphthoyl chloride distilled a t 208' under the ordinary pressure and solidified to a light lemon-yellow, crystalline mass melting at about 40" and possessing a sweet and rather nauseat- ing smell.The yield obtained was 40 grams. Condensation of P-1VaphthoyZ Chloride with the Sodium De?-ivative of E'thyl Acetoacetate. The sodium ethoxide required was first made by dissolving sodium ( 5 grams) in absolute alcohol (90 c.c.), and the solution was allowed to cool. Ethyl acetoacetate (28 grams) was weighed into a dry wide- necked bottle, and to this half the quantity of sodium ethoxide was added and the mixture well shaken. The bottle was now fitted with a mechanical stirring apparatus and the products cooled to 5' by means of ice water.P-Naphthoyl chloride (20 grams) was then dissolved in pure dry ether (75 c.c.) and half this quantity added, drop by drop, through a burette, to the sodium derivative of ethyl acetoacetate, the whole being well stirred during the addition. The process of adding the acid chloride took from ten t o fifteen minutes, and atLthe end of this time the mixture, which had assumed a bright yellow colour, was124 ETHYL 6-NAPHTHOYLACETATE. allowed to stand for half an hour, the temperature still being kept below 5". Half the remaining quantity of the sodium ethoxide was then slowly added with stirring, and then half the remaining quantity of acid chloride solution as before. The mixture, which had now become viscid, was again allowed to stand for half an hour.This process was continued until all the ethoxide and acid chloride solution had been added, the bottle was then removed from the ice water, a little dry ether added, and the whole allowed to stand overnight in a cool place. The semi-solid mass was filtered at the pump and the bright yellow sodium derivative of ethyl P-naphthoylacetoacetate washed with ether and dried on a porous plate. The crude sodium derivative, which was obtained in a yield of 51 grams, was dissolved in aqueous alcohol (10 per cent.) and mixed with an excess of dilute acetic acid, when an oil separated which, when cooled with ice, solidified to a pale pink, brittle mass. This was collected and recrystallised from alcohol with the aid of animal charcoal. The melting point was found to be 57", and the yield obtained was 17 grams.0.1942 gave 0507 CO, and 0.099 H20. C = 71.2 ; H = 5.7. C17H1604 requires C = 71.83 ; H = 5-63. Ethyl P-naphthoylacetoacetccte melts at 57" and is readily soluble in ether, alcohol, and sodium carbonate solution, and its alcoholic solution gives a reddish-violet coloration with ferric chloride. Ethy I P- Naphtho y lace t at e. Ethyl /3-naphthoylacetoacetate (1 0 grams) was finely powdered, placed in a large beaker, and dissolved in aqueous ammonia (100 c.c.), made by diluting concentrated ammonia solution with an equal volume of water. When the ester had completely dissolved, ammonium chloride (12 grams) dissolved in a small quantity of water was added, and the liquid was then well stirred and gently heated in a water- bath.The clear yellow solution gradually became milky and, after an interval of fifteen minutes, an oil was deposited which, on cooling with ice, solidified. This solid was collected a t the pump, washed with water, and recrystallised from alcohol, when very pale pink, opaque crystals were obtained which melted a t 34" and gave the following results on analysis. 0.268 gave 0.728 CO, and 0.136 H20. C = 74-08 ; H= 5-63. C,,H1,O, requires C = 74.3 ; H = 5.7. Ethyl P-naphthoylacetate is sparingly soluble in caustic soda solution ; its alcoholic solution gives a greenish-blue precipitate withLEVY ANT) STSSON : SOME NEW PLATINOCYANTDES. 125 copper sulphate and a red coloration with ferric chloride. When the ester is added to a solution of phenylhydrazine in acetic acid, a crystalline solid soon separates which, after recrystallising from acetic acid, from which it separates in golden-yellow needles, melts at 95". 0.198 gave 0,552 CO, and 0.114 H,O. 0.157 ,, 11.8 C.C. N a t 17' and 755 mm. N=8*8. C= 76.0; H= 6.39. C,,H,,O,N, requires C = 75.9 ; H = 6.02 ; N = 8.4. This substance is therefore the hydraxone of ethyl P-naphthoyl- acetate. THE VICTORIA UNIVERSITY OF MANCHESTER.

ISSN:0368-1645    

DOI:10.1039/CT9068900122

出版商:RSC    

年代:1906

数据来源: RSC

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LEVY ANT) STSSON : SOME NEW PLATINOCYANTDES. 125 XV.-Some New Platinocyanides. By LEONARD ANGELO LEVY and HENRY ARNOTT SISSON. CONSIDERING the comparatively advanced state of our knowledge of the constitution of organic substances possessing the property of fluorescence, it is remarkable that so little should be known about this phenomenon as exhibited by platinocyanides. We were accord- ingly led to investigate the effect of the basic radicle and also such conditions as hydration, purity, state of division, &c., on the character of the fluorescence. For example, the lithium salt has a red fluores- cence, whilst the sodium and barium salts exhibit yellow and green colorations respectively, these being the colours of the characteristic lines in the spectra of these metals.I n the course of our researches, we have prepared several platino- cyanides, including the hydrazine and hydroxylamine salts, of which we can find no account in the literature. These substances showed remarkable colour changes on a very slight alteration of temperature, and as these properties appeared interesting and uncommon we have investigated them further. Nydraxine platinocyanide, N2H4, H2Pt(CN),,3H20, is prepared by double decomposition bet ween equivalent quantities of hydrazine sulphate and barium platinocyanide ; the solution thus obtained, when a k w e d to evaporate spontaneously, deposits red crystals, showing blue and purple colours by reflected light. These crystals are unstable under ordinary atmospheric conditions, and, when air-dried, become partially or completely light yellow and opaque, according to the hygrometric state of the atmosphere.The transformation can always be completed by passing dry nitrogen over126 LEVY AND SISSON: SOME NEW PLATINOCYAXIDES. them. most stable in air. We analysed >his light yellow modification, this being the 0.1300 gave 24.43 C.C. nitrogen a t 16" and 748 mm. 0.3807 ,, 0.1730 CO, and 0.1049 H20. C == 12-39 ; H = 3.07. 0.2269, after heating for several hours a t looo, left a dull olive- green powder, the loss of weight being 0.0309. H20= 13.6 per cent. C,K,NGPt,3H,0 requires C = 12.40 ; H = 3-12 ; N = 21-77 ; Pt = 50.34 ; H,O= 13-9 per cent. Hydrates.-The damp red crystals become white when slightly warmed, as when a tube containing them is held in the hand, and they recover their original colour on cooling.This transformation occurs at about 28' and appears to be due to loss of water. N = 21.56. 0.2471 ,, 0.1246 Pt. Pt=50*42. We arrived at this conclusion from the following facts : (i) The red crystals, when partly exposed to air, pass through the white form before becoming yellow. (ii) The red modification becomes white when dry nitrogen is passed over it. (iii) Methyl alcohol turns the red crystals white before dissolving them. This white modification is very unstable a t the ordinary tempera- ture, and rapidly becomes red and yellow on exposure t o air. No determination of the percentage of water is possible owing to the rapidity with which this change occurs. The state of hydration of the red salt cannot be accurately estimated, as it is very unstable when dry.This red salt may be kept in a damp atmosphere, but the amount of adherent water would vitiate any analysis. When pure dry nitrogen is passed over the red salt, its colour changes in succession to white, then light yellow, dark yellow, brown, and olive-green. An approximate estimation of the water in the red modification was obtained by passing dry nitrogen over the salt until it became yellow. 0.1500 gram, when so treated, gave 0.1409 gram of yellow salt. The loss of one and two molecules of H,O require respectively 0.1432 and 0.1366 gram of the yellow salt. Hence this hydrate probably contains four molecules of water. The slightly greater loss of water is probably due to dampness of the red salt. The latter fluoresces faintly under radium, but no more brightly than does glass under similar conditions.All modifications are readily soluble in methyl alcohol, from which they are wholly precipitated by ether. The colour of the precipitate varies according to the amount of water present and may be red, purple, orange, yellow, or white. If the process is repeated onceLEVY AND SISSON : SOME NEW PLATINOCYANIDES. 127 or twice on the precipitate, a pure white, crystalline salt can always be produced. When thus obtained, it is even more unstable than when prepared by the method already described. A print can be obtained from a negative by placing it over a sheet of paper soaked in the methyl-alcoholic solution and allowed to dry. The print thus obtained is yellow and grey and shows details fairly well. We have not yet been able to fix this image, which is destroyed by damp, but can be reprinted when dry.The paper is also attacked and becomes brittle. If h ydrazine platinocyanide is prepared with excess of barium platinocyanide, fine red crystals are obtained together with some normal salt. These are permanent in air, contain barium, and, on heating to about 60°, or when placed in a vacuum desiccator, become opaque and assume a lustrous, beetle-green colour. We intend to pursue the investigation of these substances. Hydroxykumim Platinocyanide, (NH20H),H2Pt( CN),, 2 H20. -This salt is prepared by double decomposition between barium platino- cyanide and hydroxylamine sulphate. The solution thus obtained, when allowed to evaporate spontaneously, leaves very soluble red crystals stable in air at the ordinary temperature.Action of Light.-Hydrazine platinocyanide is affected by light. 0.1475 gave 26.1 C.C. nitrogen a t 17" and 751 mm. 0.2338 ,, 0.1132 Pt. Pt = 48.42. 0.2387, after remaining in a vacuum desiccator over sulphuric acid, gave a black powder, the loss of weight being 0.0217 ; H20 = 9.09 per cent. C,H8N,Pt,2H,O requires N = 20.8 ; Pt = 48.39 ; H,O = 8.93 per cent. Hydrates.-The red crystals become bright yellow when slightly warmed, and this is exactly analogous t o the colour variations occur- ring with the hydrazine salt and takes place quite as readily. These yellow crystals again become red on cooling; the salt is soluble in methyl alcohol, but is not satisfactorily precipitated by ether.The change from red to yellow is accompanied by loss of weight. The foregoing salts are the first members of a series of platino- cyanides which we hope shortly to prepare in the course of our investigations on the effect of the molecular weight of the base on the character of the fluorescence, We propose to prepare platinocyanides of alkyl-substituted hydrazines, hydroxylamines, and other bases, thus obtaining a series of platinocyanides the molecular weights of which differ by equal or known increments. The more common aromatic bases, such as phenylhg drazine, do not yield the well-crystallised salts so essential for the purpose of comparing their fluorescence. Platinocyanides of fluorescent bases or radioactive substances should N = 20.3.128 SLATOR : STUDIES IN FERMENTATION. I. prove of special interest. The radium salt should be self-luminous, and an investigation of its fluorescent properties might throw some light on the origin of the fluorescence conferred by the platinocyanide group on its salts. Most of the materials necessary for the foregoing researches have been purchased by means of funds kindly supplied by the Government Grant Committee of the Royal Society. Our thanks are due to Dr. H. J. H. Fenton, F.RS., for valuable advice. CHEMICAL LABORATORY, CAMBRIDGE UNIVERSITY.

ISSN:0368-1645    

DOI:10.1039/CT9068900125

出版商:RSC    

年代:1906

数据来源: RSC

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128 SLATOR : STUDIES IN FERMENTATION. I. XVI.--Studies an Permentation. I. The Chemical Dynamics of Alcoholic Fermentutioiz by Yeast. By ARTHUR SLATOR, Ph.D. THE study of the velocity of chemical reactions consists to a large extent of the investigation of the dependence of the velocity on the concentrations of the reacting substances and certain accelerating and inhibiting agents. The concentrations of the reagents are varied and the corresponding velocities measured. If the chemical change in question is unaccompanied by disturbing side reactions, the simplest method of changing the concentrations of the reagents is to allow these substances to be used up in the reaction, I n such cases, an integrated formula is employed to calculate the results, which are usually expressed in the form of ‘‘ constants ” or values of K.If these values of K remain constant throughout the reaction, this is probably the best method of investigation. If through any disturbing influences the values do not remain constant, the results expressed in this way are sometimes difficult to interpret and may even be misleading. I n these cases the more direct method of investigation is desirable. The velocity of the chemical change is measured over as short a range of the reaction as is consistent with accuracy, and the concentrations of the reagents altered by dilution with the solvent. This method of considering only initial velocities is the one best employed in the investigation of the reaction which forms the subject of the present communication. The dynamics of the fermentation of sugars under the influence of yeast and various preparations from yeast has been studied by a number of investigators, and many methods have beenSLATOR : STUDIES IN FERMENTATION.I. 129 used to follow the reaction. If we consider the fermentation of dextrose C,H,,O, = 2C,H,*OH + 2CO,, it is evident that the reaction- velocity can be measured by observing the rate of decrease of dextrose, or the rate of formation of alcohol or carbon dioxide. Dumas (Ann. Chim. Phys., 1874, [iii], 81) uses the copper reagent test for dextrose and observes the time for complete fermentation. A. J. Brown (Trans., 1892, 61, 369) and J. O'Sullivan (J. Suc. Chem. Ind., 1898, 17,559; J. Inst. Brewing, 1899,5,161) estimate in some experiments the alcohol formed, in other cases the change in optical activity owing to disappearance of the sugar. The latter method is also used by A.L. Stern (Trans., 1899, 75, 201) in his experiments on yeast growth during fermentation, and also by J. H. Aberson (Rec. trau. chim., 1903, 22, 78) in his measurements of the velocity of fermenta- tion throughout the whole range of the reaction. Buchner (Die Zymase- garung, 1903, E. Buchner, H. Buchner, M. Hahn) workiug with yeast- juice, R. 0. Herzog working with '' zymin "-yeast treated with acetone (.Zeit.physiuZ. Chem., 1902, 37, 149), and H. Euler also using yeast-juice, estimate volumetrically or gravimetrically the amount of carbon dioxide evolved. The methods devised by these investigators require the fermentation to proceed for some time before the velocity can be accurately measured.Although many interesting and important facts have been discovered in these researches, it is probable that a more sensitive method of investigation would lead to a greater knowledge of the reaction. A modification of the method of estimating the carbon dioxide evolved seemed to offer a degree of sensitiveness greater than that obtained by other workers. I f a sugar solution undergoing fermenta- tion is placed in a closed vessel, the amount of carbon dioxide liberated can be estimated by the pressure produced. Thus 50 C.C. of a 10 per cent. dextrose solution fermenting in a flask of 150 C.C. capacity a t a temperature of 15' gives a change in pressure of 1 cm. of mercury for a fermentation of 7.4 milligrams of dextrose." An apparatus constructed on the principle of measuring the rate of fer'mentation by change in pressure due to the gas evolved was found to be workable and to give concordant results.This method differs from those mentioned above in that the time of the experiment extends over only a few minutes, only small quantities of sugar are fermented, and only a very small range of the reaction is considered. * I n the calculation, it is assumed that the solution is well shaken t o overcome supersaturation. At 15", the concentration of carbon dioxide is approximately the same in the gaseous as in the liquid phase. VOL. LXXXIX. K130 SLATOR : STUDIES IN FERMENTATION. I. The Apparatus and Method of Investigation. Details of the apparatus for estimating the rate of fermentation are as follows: an ordinary glass bottle of about 150 C.C.capacity, with a fairly narrow neck, is connected by a piece of pressure tubing to a manometer as represented in the figure. The side-tube is connected to the pump in order P to exhaust the apparatus, which is then kept air-tight by means of the tap T. The reacting solution, usually 50 c.c., is placed in the bottle, which also contains twenty t o thirty fairly large glass beads in order to assist in the thorough shaking of the solution. The bottle rests in a thermostat and during the experiment is taken out at intervals and shaken vigorously by hand, so that the carbon dioxide in the solution is in equilibrium with that in the space above. The pres- sure at the beginning of the ex- periment is usually 3-4 cm.of mercury. The change in pressure registered on the metal scale of the manometer is a measure of the amount of fermentation. Through- out this investigation, only relative amounts are measured by a direct comparison of the manometer read- ings in parallel experiments. To the solution containing sugar and yeast was usually added a small quantity of nutrient salts (3 grams of asparagine, 1 gram of K2HP04, 0.5 gram of MgS0,,7H20'in 1 litre), although it was found later that these salts had little influence on the initial rate of fermentation. The InJEuence o f the Amount of Yeast on the Velocity of Fermentation. The influence of quantity of yeast on the velocity of alcoholic fermentation has been examined by 5. O'Sullivan (Zoc. cit.) ; the experi- ments are, however, probably complicated by change in activity of the yeast.I f such complications are eliminated, the influence of theSLATOR : STUDIES IN FERMENTATION. I. 131 Concentration of the yeast can be predicted, for if each cell acts individually then the velocity of fermentation must be proportional t o the concentration of the yeast. The following tests show that this result can be experimentally realised. Some brewery yeast was shaken up with water containing a small quantity of nutrient salts. The rates of fermentation of six solutions of five per cent. dextrose con- taining respectively 1, 3, 5, 10, 20, and 25 C.C. of the yeast mixture were measured and shown to be almost exactly in the ratio of the concentrations of the yeast.The experiments were carried out in the manner described at a temperature of 30°, for at this temperature the activity of the yeast is unaltered during the time of the experi- ment. Details of the measurements are given in Table I, where t = time in minutes, P = manometer reading in cm., B = differences in equal time intervals. TABLE L-Th InJEuence of the Concentration of Yeast on tihe Velocity of flerrnentation. Temperature = 30'. 1 C.C. t. P. D. 0 minutes 6-5 cm. - 30 7 ) 8-05 1-55 60 7 , 9-7 2 , 1 *65 Velocity = 0'533 cm. per 10 minutes. 5 C.C. t. P. D. 0 minutes 6.6 cm. - 10 7 ) 9.25 ,, 2-65 20 7 7 11.9 7 , 2.65 30 7 , 14-55 2.65 Velocity = 2.65 cm. per 10 minutes. 20 C.C. 1. P. D. 0 minutes 8-45 cm. - 5 9 ) 13-85 ,, 5.4 10 7 , 19'05 ), 5.2 Velocity = 10'6 cm.per 10 minutes. Vol. of solution = 50 C.C. 3 C.C. t. P. 0 minutes 6.9 cm. 10 > 7 8.5 7 ) 20 9 , 10.15 7 7 30 7 ) 11.8 ), Velocity = 1'63 cm. per D. 1 -6 1.65 1 *65 0 minutes. - 10 C.C. t. P. D. 0 minutes 7 *15 cm. - 5 7 ) 9.8 > 7 2.65 10 7 , 12'5 )) 2.7 15 2 7 15'2 ,) 2 *7 Velocity = 5'36 cm. per 10 minutes. 25 C.C. t. P. D. 0 minutes 6'8 cm. - 2 7 , 9.45 ) ) 2-65 14-85 ,) 2x2'7 6 > > 8 > ) 17.45 ), 2% 10 7 , 20-05 ,, 2% Velocity = 13-25 cm. per 10 minutes. Yeast concentrations = 1 : 3 : 5 : 10 : 20 : 25 Velocities = 0.99 : 3'04 : 4'94 : 10 : 19.8 : 24.7 The concordance in the values of D in the single experiments and the agreement in the ratios of the concentrations and velocities give a K 2132 SLATOR : STUDIES IN FERMENTATION. I. satisfactory proof of the reliability of the method of investigation.These numbers give us no indication of the change in velocity corre- sponding to the change in the concentration of the enzyme, as the enzyme is contained in the yeast cell. Euler working with yeast juice and Herzog working with ‘‘ zymin ” give values of n = 1.29-1.67 and 2.0 respectively, where n is calcu- lated from the formula KJK, = (C,/C2)n, K, and K2 being the velocity constants corresponding to the concentrations of ferment C, and C,. If C, and C, are concentrations of yeast, n = 1.00 from Table I. The velocity of fermentation is therefore a measure of the quantity of active yeast present. With ordinary brewery yeas:, 10 cells per 1/4000 c.mm. at 30” gave an average velocity of about 4.5 cm. per ten minutes on the manometer scale of the apparatus.The Influence of thu Concentration, of Dextrose on the Bate of Ferment at ion. It has been shown by Dumas (Zoc. cit.), Tammann (Zeit. physikal. Chem., 1889, 3, 25), A. J. Brown (Zoc. cit.), and J. O’Sullivan (Zoc. cit.) that the rate of fermentation is practically independent of the concen- tration of sugar. This is also the case in the fermentation by yeast- juice. H. Euler (Zoc. cit.) has shown that the values of K calculated for a unimolecular reaction vary with the initial concentrations of dextrose and are numbers proportional to the velocity of fermentation concentration of sugar ’ and, as he shows that they are approximately inversely proportional t o the concentration of the sugar, it is evident that the fermentation velocity is independent of the concentration of dextrose.The con- 1 a stancy of the values K=-.log- for a small part of the reaction t a-x is due probably entirely to the enzyme being slowly destroyed. J. H. Aberson (Zoc. cit.) also considers the reaction to be unimole- cular, whilst Herzog (Zoc. cit.) uses both the unimolecular formula and Henri’s empirical formula (Zeit. physikaz. Chem., 1901, 39, 194) to calculate his results. On examining their data, it is, however, clear that the reaction is approximately independent of the concentration of the sugar. This result has been confirmed and extended by this method of investigation. Solutions containing the same amount of yeast, but different amounts of dextrose (0.2-20 grams of dextrose per 100 c.~.), were tested, and the results are given in Table TI.From this table and the accompanying curve, it is seen that with this concentration of yeast and at this temperature a maximum velocity isSLATOR : STUDIES IN FERMENTATION. I. 133 reached with about 5 grams of dextrose per 100 C.C. ; the change in the velocity of fermentation between 0.5 gram and 10 grams per 100 C.C. is, however, only slight, Below 0.5 per cent., the concentration has an influence, and above 10 per cent, the excess of sugar has a distinct retarding influence. TABLE II.-InJZzcence of the Concentration of Dextrose. Temperature = 30'. Grams of dextrose Velocity in cm. per 10 minutes. per 100 C.C. 0-16 2 -9 0.28 4 *05 0 '52 4'7 0'66 5 -1 1 '0 4 '8 2.0 5 '2 Grams of dextrose Velocity in cm.per 100 C.C. per 10 minutes. 4'0 5.5 5.0 5 *4 8.0 5-05 12.0 5.05 20.0 4'4 I n the study of the velocity of enzyme actions, it is often found that when the concentration of the reagent in question is large compared to that of the enzyme, the change p r w e J s as a linear function of the time ; with relatively larger concentrations of enzyme the logarithmic law holds, as, for example, in hydrolysis by invertase (C. O'Sullivan and P. W. Tompson, Trans., 1890, 57, 843; A. J. Brown, Trans,, 1902, 81, 373), hydrolysis by diastase (Horace Brown and Glendinning, Trans., 1902,81, 388 ; Victor Henri, " Lois ghhrales des diastases," Paris, 1903), and in hydrolysis by sucroclastic enzymes (E. F. Armstrong, Proc. Roy. Soc., 1904, 73, 500, 516, 526; 74, 188, 195). It is therefore of interest to examine these data more closely and see whether these two stages of the reaction can be traced.The numbers can best be studied by calculating " n " the order of the reaction with regard to the sugar according to the equation VJ V, = (C,/C,)m, where Vl and Vz are velocities corresponding with concentrations of dextrose C, and C,. If 12 = 0, V is independent of C, and the change proceeds as a linear function of the time, I f n = 1, V is proportional to C, and the logarithmic law holds. The results are summarised in Table 111, where 1.1 is calculated from a number of experiments with different concentrations of sugar. The134 SLATOR : STUDIES IN FERMENTATION. I. experiments at 20' are carried out with about twice the quantity of yeast used in those at 30".TABLE 111. Cl : C2 in grams of Temp. dextrose per 100 C.C. TI : Vp 30" 0.16 : 0.52 1 : 1'62 (from Table 11). 0'28 : 0.66 1 : 1-26 1 : 2 1 : 1-08 2 : 4 1 : 1.06 4 : 8 1 : 0.92 8 : 20 1 : 0.87 0.09 : 0-34 1 : 1-60 0.6 : 1.02 1 : 1.17 1'12 : 2.53 1 : 1'24 2.85 : 8.55 1 : 1'13 10 : 20 1 : 0'90 20" n. +0'41 + 0-27 + 0.11 + 0'08 - 0.12 - 0.15 +0*35 + 0.30 + 0.26 + 0.11 - 0.15 The value of ' 1 ~ for higher concentrations is approximately zero and increases as the concentration becomes less, but never reaches 1. The influence of the concentration of dextrose is therefore never so great that the velocity is proportional to this concentration. This enzyme action thus differs from those already studied in that the logarithmic part of the curve has not been realised with these concentrations. The results obtained in these experiments may be summarised by the differential equation : d(dextrose) - dt - + - d(carbon dioxide) dt 112 7% K.(yeast) (dextrose) , where m = 1 using the same yeast, varies with the concentration of dextrose and yeast, but for the main part of the reaction is approxi- mately 0. With dilute solutions of sugar, values up to 0.5 have been obtained.The fact that the velocity of fermentation is independent of the concentration of the sugar is most simply explained by the assumption of the formation of a compound between the enzyme and the sugar (compare Horace T. Brown and Glendinning, Eoc. cit. ; E. F. Armstrong, Proc. Roy. ~oc., 1904, 73, 502). If with a certain concentration of sugar the main part of the enzyme is combined with sugar, a further addition of the latter reagent would not appreciably alter the amount of this compound.I f the velocity which is experimentally measured is the rate of decomposition of the compound or the rate of a reaction involving this compound, then the velocity under these conditions would be independent of the concentration of dextrose. The sugar concentration would have an influence when the concentrations are such that an appreciable quantity of enzyme is left uncombined. If the mechanism of fermentation is worked out on this hypothesis, we have the sugar diffusing into the yeast cell and combining with theSLATOR : STUDIES IN FERMENTATIOE. I. 135 enzyme. This compound decomposes either directly or indirectly into alcohol and carbon dioxide with regeneration of the enzyme and immediate formation of more compound.Of this series of processes, diffusion, combination, and decomposition of the compound, the latter is the reaction which proceeds slowest, and is therefore the important one in determining the reaction-velocity. The reactions which precede this serve to bring the reagents which take part in the slow reaction up to a certain concentration, and any subsequent reaction serves to remove the primary products, forming alcohol and carbon dioxide. I n dealing with living yeast cells, it must not be forgotten that the reaction takes place within the cell, where little is known of the concentration OF the reagents, and this mechanism of fermentation can only be accepted as a working hypothesis.Some other results are not easy to explain by this mechanismof reaction. Thus, if the enzyme is completely combined with the sugar, the amount of compound formed must be proportional to the amount of enzyme present, and proportion- ality should exist between the concentration of the enzyme and the velocity of reaction. This is difficult to bring into harmony with Herzog's experiments showing that the velocity is proportional to the square of the concentration of the zymin (Zoc. cit., p. 159). It is also a question whether the enzyme is entirely regenerated. The values of K calculated from the formula for a unimolecular reaction in Herzog's series of experiments show a fair degree of constancy through a large range of the reaction. This is evidently due to the enzyme being decomposed during fermentation, and not to the disappearance of sugar, for the values do not agree in different experiments with vary- ing initial concentrations of sugar.This is shown in Tables Icc and I1 (Zoc. cit., pp. 153, 154), where the same quantity of zymin is used, but different initial concentrations of sugar. Temperature = 24.5'. 11. I 1C6. Dextrose concentration, n = l = 20'45 grams per 100 C.C. a=0*5. 1.2 grams of zymin per 10 C.C. 1 1.2 grams of zymin per 10 C.C. 0.4343 K= t. a .- z. l / t log. ./a - x. 120 0'961 0'000144 * 240 0'922 0.000147 1200 0.673 0-000143 2690 0'396 0 '000149 3000 0'359 0*000150 t. a-x. 0'4343K. * 240 0-409 0 *000363 420 0'349 0*000374 1440 0'142 0.000379 1740 0.119 0.000359 The initial velocity in the concentrated solution (calculated from the values in 240 minutes) is slightly less than in the dilute instead of136 SLATOR : STUDIES IN FERMENTATION.I. being double, as would be the case with a true unimolecular reaction with regard to the sugar. The In&hence of Temperature. It is well known that the rate of fermentation is greatly influenced by temperature. Aberson (Eoc. cit., p. l05), working between 1 2 O and 3 3 O , gives a mean temperature quotient for 10' (K,+,,/Kt) 2.72. Herzog (Zoc. c i t . , p. 160) gives values of the velocities from 14.5' to 28-5O, K24.5/K14.5 = 2.88. Some preliminary experiments with the apparatus described confirmed these results, but showed that the temperature quotient varied with the temperature. An investigation was therefore undertaken over as large a range of temperature as possible. Below 5O, the reaction proceeded too slowly to be measured, whilst above 40° the enzyme was destroyed.Experiments were therefore carried out between these temperatures. The method of working was a6 follows : the velocity was measured at a given temperature in the manner described, the temperature was then quickly raised 5' and the velocity again measured. The apparatus was then cooled to the original temperature and a third measurement of the velocity taken. The mean value of the velocities in the first and third experiments was compared with that in the second, and in this may change in activity of the yeast was eliminated. An example will make this clear. Time for pressure to change by 4 cm. of mercury.Temperature. 20" 18.2 minutes 20 14'2 ,, 25 9.7 > > Ratio of observed velocities = 16*2/9*7 = 1.67 : 1. A small correction, amounting in this case to 5 per cent., has to be made for the decreased solubility of the carbon dioxide a t the higher temperature, and for the influence of temperature on the pressure. Applying this correction, the ratio of the velocities VZs/Y2,, = 1.59. Other experiments gave 1-52, 1.56, 1-60 ; mean 1.57. Table I V gives the result of a series of experiments between the temperatures 5' and 40'. The value K+5/Vt is obtained from the observed ratio by applying the solubility correction given in the third column. As temperature-coefficients are usually given as quotients €or lo', mother column i s added, giving the values V,+,,/Vt at various temperatures,SLATOR : STUDIES IN FERMENTATION.I. 137 Temperature. 10 15 20 25 30 35 40 5" 0 bserved ratio. 2.94 2-29 1 *89 1.65 1-50 1 *43 1.27 TABLE IV. Peruen tage correction. * Vt+5/ Vt. 10 2.65 8 2'11 5 1 *so 5 1 -57 5 1'43 5 1-35 5 1 *20 Vt+,,/ Vt. Herzog. Aberson. 5.6 3 3 2.8 2.88 2'72 2 -25 1 *95 1% * These corrections are calculated for 50 C.C. of solution fermenting in an appa- ratus of 140 C.C. capacity. It may be now pointed out that if the chemical action brought about by yeast is due to a definite enzyme in the cell and that the enzyme is the same in different kinds of yeast, then certain character- istics of the reaction will remain the same independently of the class of yeast used to excite fermentation. The temperature-coefficient would probably be one of these constant factors.The experiments were therefore extended to an examination of other yeasts. The tempera- ture quotients for 5' of the fermentation reaction with some '' distillery " yeast and '' wine " yeast were found to be practically identical with those obtained with '' brewery" yeast, and we may therefore conclude that the enzyme present in the three kinds of yeast is the same. TABLE V.-Temperature Quotients with Diferent Yeasts. " Brewery" " Distillery" " Wine " yeast. yeast. yeast. 2 %5 2.50 2.30 2.11 1.97 1-85 1-80 1 -98 1'96 1.57 1'62 1 '62 1 '43 1.47 1'41 1 -35 1'36 1 '33 1 *20 1.26 . 1 '24 Mean. 2.50 1 -98 1 *91 1'60 1 '44 1-35 1-23 In the study of enzymes it is very seldom found that these substances can be characterised in any but a qualitative manner.They cannot be isolated and analysed, and the velocity of the reaction which they bring about is usually very sensitive to inhibiting agents, and cannot be used directly as a means of identification. We have, however, in the temperature-coefficient of the reaction numbers which seem to be characteristic of the enzyme zymase and may serve this purpose. These numbers were found to be independent of the concentration138 SLATOK. : STUDIES 1N FERMENTATION. 1. of yeast and dextrose, the class of yeast, presence or absence of nutrient salts, and the same when inhibiting agents are present (Table TIC). This enzyme occurs not only in yeast and in various preparations from yeast, but also in different animal and vegetable tissues, and these numbers may be of value in proving the identity or otherwise of zymase obtained from various sources.The Bate of Permentation of Dzferent Sugars. It is known that the various fermentable sugars undergo fermenta- tion at almost the same velocity, and the few experiments which are given below confirm this result. If this is true for dextrose and I=vulose, then it would also be probably correct for sucrose and maltose, as enzymes are present in the yeast which hydrolyse these disaccharides, giving the fermentable monoses. The numbers given in Table VI show that Isevulose is fermented somewhat more slowly than dextrose, sucrose a little faster, and maltose at the higher temperature with almost the same velocity as dextrose, and at a lower temperature somewhat slower.TABLE VI. Velocities of fermentation. Grams of sugar Temp. in 100 C.C. 3 0” 5 30 5 25 5 25 4 25 10 Dextrose. 7- In cm. per 10 mins. Lzvulose. Sucrose. 2.5 100 91 103 5’25 100 90 2.95 100 - 106 2.0 100 94 6 ‘2 100 91 - - - Maltose. 101 - - 84 The velocities are all referred to dextrose as 100, and the actual velocities with this sugar are given in order to indicate the quantity of yeast present. It is remarkable that constant values of the velocity of fermentation of maltose and sucrose are obtained in a few minutes showing that enough sugar is almost instantaneously hydrolysed for the fermentation reaction to attain its maximum velocity. The Action of Inhibiting Agents. Enzyme actions are peculiarly sensitive to inhibiting agents or “poisons,” and a study of the action of such poisons affords some insight into the nature of the enzyme.Thus Senter, on measuring the retarding influence of acids on the rate of decomposition of hydrogen peroxide by hzemase, an enzyme isolated from blood, shows that this effect is approximately proportional to the H’-ion, and concludes thatSLATOR : STUDIES IN FERMENTATION. I. 139 the enzyme is probably a weak base (PYOC. Roy. SOC., 1904, 74, 204; Zeit. phgsikal. Chem., 1905, 51, 680). E. F. Armstrong (Zoc. cit.) has been able t o show, by the inhibiting action of certain sugars on sucro- elastic changes, a close correlation in configuration between enzyme and hydrolyte. Many ‘‘ poisons ” have been discovered which inhibit alcoholic fermentation, but some preliminary experiments with this apparatus showed in many cases the great influence of the “incuba- tion” time on the activity of the poison.Moreover, as one is dealing with a mixture of a great many substances, there are present so many disturbing influences that a quantitative estimation of the action of small quantities of poisons cannot be carried out as Senter has done for hfemase. The investigation was continued on somewhat different lines in the hope of throwing some light on the mechanism of the reaction. From considerations already discussed, the following steps in fermentation will be assumed. A . Diffusion of the sugar into the cell. B. Combination of dextrose and enzyme. C. Decomposition of the compound forming an intermediate com- D. Decomposition of this compound forming carbon dioxide and E.Diffusion of the products from the cell into the solution. Of this series of reactions, C is the one which proceeds slowly, and the velocity of this reaction is measured in these experiments. If an intermediate compound exists-the supposed formation of lactic acid has attracted so&e attention lately (Buchner and Meisenheimer, Ber., 1904,37, 417 ; McKenzie, Trans., 1905,65, 1378)-then reaction B must proceed rapidly to prevent accumulation of this compound. The action of ;L poison on this system may be that it retards any one of the five reactions. If, for example the poison prevented the diffusion of sugar into the cell sufficiently to influence largely the rate of forma- tion of the end-products, then reaction A would be the slow reaction of the series and would be the important one in velocity measure- ments.The characteristics of the inhibited reaction would then be the characteristics of the diffusion reaction A and would probably be very different to those of reaction C which is primarily measured. To put the matter generally, whichever reaction is retarded by the poison, this reaction becomes the important one in determining the velocity of formation of alcohol and carbon dioxide. It seemed of interest, therefore, to investigate whether the temperature -coefficien t of the inhibited reaction is the same as that of the original reaction. This characteristic mas chosen as being easily and rapidly measured. Table VII gives a summary of the results obtained, and it is evident that in all these cases the temperature quotient for 5 O is practically pound (lactic acid 2).alcohol.140 SLATOR : STUDlES IN FERMENTATION. I. identical with that of the original reaction, showing that the '' poison " is inhibiting the reaction which determines the velocity in these experimer, ts. TABLE VII.-Temperature-coeficient of the Reuction inhibited 69 Xu Zphuric Acid. 50 C.C. of solut,ion. Temp. Time to fall 3 cm. Without acid .................. 25" 6.7 minutes t 5 C.C. 3 7 5 IJ,SO, 25 6'2 2 1 After 4 hours 25 9'4 ), ,, 7 ,, .................. 25 18.4 ,, 30 12.9 ,, (caled. for 25"=20'4) 35 22'4 ), ......... .................. Ratio of times= 1 -58 : 1. Y30/ Yzs = 1.50. From Table IV = 1 -43. 50 C.C. of solution. Temp. Time to fall 6 cm. Without acid ..................15" 14'8 minutes + 5 C.C. N/5 H,SO, ......... 15 14'4 ,, After 6 hours .................. 15 19'1 ,, 20 10.3 ,, (calcd. for 15"=20'lj 15 21.0 ,) Ratio of tirnes=1-95 : 1. ~,,/y,,=1'85. From Table IV=1*80. Summary. Percentage reduction on the velocity. Concentration of " poison." 0'02N H,SO, ........................ 67 O*02N H,SO, ........................... 26 O.035N oxalic acid .................. 67 8 per cent. alcohol ..................... 40 50 0.004 per cent. mercuric chloride.. . For original reaction from Vt+,/Yt. Table IV. V30/V25 = 1.50 1 -43 v20/v15 = 1'85 1 -80 V3,/Y2, = 1-40 1 *43 Y&/Y25 = 1-39 1 '43 V30/Yz6 = 1'40 1'43 It is interesting to note that in the case of sulphuric acid the first effect is a slight raising of the velocity and then a gradual fall in the activity of the yeast.The enzyme is in some way rendered inactive, and is probably destroyed, for on neutralising the acid the activity is not regained. It was found that the sugar to a certain extent protects the enzyme against the acid, a point in favour of the view of a com- bination between the enzyme and sugar. Thus, yeast which has been allowed to stand three hours at 25' with sulphuric acid (0.02iV) lost 53 per cent. of its activity, whilst when dextrose was present the loss was only 29 per cent. The addition of lactose to a ferment- ing solution has practically no influence on the rate of evolution of carbon dioxide. A 5 per cent. dextrose solution fermenting at the rate of 5.7 cm. per ten minutes on the addition of the same quantity of lactose gave a velocity of 5.95 cm.per ten minutes.SLATOIt : STUDIES IN FERMENTATION. I. 141 Lactic Acid us an Intermediate Compound in Fermentation. It has been suggested that lactic acid is an intermediate compound in the fermentation of dextrose, and that two enzymes take part in the reaction : zymase, which converts dextrose into lactic acid, and lactacidase, which converts the lactic acid into alcohol and carbon dioxide (Buchner and Meisenheimer, Ber., 1905, 38, 620). Velocity experiments do not, however, confirm this supposition. On adding small quantities of lactic acid to a fermenting solution, no very appre- ciable change in the velocity is noticed. As the second reaction (Reaction D, p. 139) must proceed more quickly than the first (Reaction C) in order to prevent a large accumulation of lactic acid, we should expect a very considerable increase in the velocity of evolution of carbon dioxide in the presence of lactic acid.Temp. 30”. 5 per cent. dextrose solution. Without lactic acid ............ 4.9 cm. per ten minutes. 0.007N ,, ,, .......... 4.65 ,, ,, 97 0.05N ,, ,, ............ 4.5 ,, ,, 9 ) Buchner and Meisenheimer’s conclusions are based on experiments which show the appearance and disappearance of lactic acid in certain fermentation experiments. The results are perhaps more easily explained on the supposition that lactic acid is formed by some side reaction and not in an intermediate reaction. A small quantity of sugar may be converted into lactic acid, which is subsequently con- verted into alcohol, but i t is improbable that all the sugar goes through this intermediate step. If an intermediate compound exists, it is probably much less stable than lactic acid, and would be difficult to isolate.The chief results obtained in this paper may be summarised as follows : 1. I n the study of the rato of alcoholic fermentation, many com- plications are eliminated by measuring the velocity over very small ranges of the reaction, and changing the concentrations by dilution. 2. The change of pressure due to evolution of carbon dioxide is a convenient and sensitive method of measuring this velocity. 3. The rate of fermentation of dextrose is proportional to the con- centration of yeast over a wide range of concentrations. 4. The rate is almost independent of the concentration of the sugar except in very dilute solutions. The influence of this concentration is never so great that the velocity is proportional to the concentration142 SMITH: THE SLOW COMBUSTION OF of the sugar; the reaction is therefore never one of the first order with regard to the sugar. 5. The temperature-coefficient of the reaction is large and varies with the temperature. V15/V5 = 5.6, Y40/V30 = 1.6, and intermediate values are obtained between these temperatures. The temperature quotient for 5" from 5' to 40' forms a series of numbers which seems to be characteristic of the enzyme zymase. 6. The initial rates oE fermentation of dextrose, lzevulose, sucrose, and maltose are in the ratio 1 : 0.92 : 1.05 : 0.9. 7. The temperature-coefficient of the reaction inhibited by '' poisons " is the same as that of the original reaction. 8. It is improbable that in fermentation any but small quantities of sugar go through the intermediate step of lactic acid. 9. These results indicate that the reaction which is measured in these experiments is the slow decomposition of a compound between the enzyme and the sugar. I n conclusion, the author wishes to acknowledge his indebtedness to Mr. C. O'Sullivan, F.R.S., and Dr. A. L. Stern, with whom he had the advantage of discussing the matters treated in this paper.

ISSN:0368-1645    

DOI:10.1039/CT9068900128

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

142 SMlTH: THE SLOW COMBUSTION OF of Carbon Disutphide. By NORMAN SMITH. IN 1890 (Brit. Assoc. Reports, p. 776), G. S. Turpin showed that carbon disulphide undergoes a ‘‘ slow combustion ” at temperatures as low as 130’ with the formation of a dark reddish-brown substance. H e states that “this powder contains both carbon and sulphur, but its composition has not yet been thoroughly made OU~.’’ Dixon and Russell (Trans., 1899,75,603), in their investigation of the combustion of carbon disulphide, also noticed the formation of this reddish-brown substance at temperatures below that at which explosion of the mixture of carbon disulphide and oxygen takes place. During the last four years, the author has been engaged in the investigation of this reddish-brown deposit. The chief difficulty has been the small amounts of substance which could be obtained. In the earlier experiments, a stream of air mixed with a small quantity of oxygen was drawn over the surface of some carbon disulphide and then through a long tube heated at temperatures varying from 130-190’.A reddish-brown film gradually formed on the sides ofCARBON DISULPHIDE. 143 the tube. If boiling water was poured into the tube, the film peeled off, and on analysis was found to contain carbon, sulphur, hydrogen, and oxygen, the hydrogen and oxygen being approximately in the same proportion as in water. Experiments were next carried out to determine whether moisture was necessary for the formation of the deposit. The carbon disulphide was dried by calcium chloride, and the mixture of air and oxygen passed through sulphuric acid before use.In all the experiments where moisture was excluded, no deposit could be obtained. On the other hand, it was found that, if the gases were quite moist, the action took place much more readily. Various methods have been tried to increase the yield, but with little success. The introduction of platinum gauze into the heated tube did not appear to cause any increase in the rate of formation of the substance. Finally, the method adopted as giving the best results was the following: a mixture of carbon disulphide and water vapour, obtained by bubbling an inert gas (carbon dioxide or nitrogen) through a tube containing pure carbon disulphide covered with a layer of water, was passed through glass tubes about 90 cm. long and 3 cm.in diameter. These tubes were packed with lengths of glass tubing of 3 to 4 mm. bore, and heated in a large Lothar-Meyer air-oven, kept at 175-180". By means of a T-piece, oxygen was mixed with the carbon disulphide and water vapour just before the gases entered the heated tube. The most favourable proportion was obtained when slightly less oxygen than that which would cause explosion was introduced into the mixture. The heated tube became slowly covered with the reddish-brown film; in the cooler portions, a very light black powder, resembling soot, was deposited, although in extremely small quantities, whilst from the end of the tube a faint smoke was emitted. The issuing gases contained a considerable quantity of sulphur dioxide, but only a very small amount of carbon dioxide could be detected.The film peeled off much more readily when a hot solution of sodium carbonate was used instead of boiling water. After drying, the substance was very light; it was dark brown and had a bright lustre. It decomposed when heated strongly, yielding dark yellow fumes with a smell resembling the mercaptans, and a hard black mass insoluble in alkali was left. The substance was insoluble in the usual organic solvents, such as alcohol, ether, benzene, aniline, &c. Water and carbon disulphide dissolved a small quantity, but only sufficiently to colour the liquid faintly. With the exception of the small amount of black powder, all dissolved readily in a hot solution of caustic alkali forming a dark brown solution.On acidifying this solution, a reddish-brown, flocculent precipitate, resembling ferric hydroxide, was deposited. This, on drying, changed to a hard, black solid.144 THE SLOW COMBUSTION OF CARBON DISULPHIDE. Tbe deposit taken from the tubes generally contained a little free After removal of this by repeated digestion wihh carbon sulphur. disulphide, the slightly varying analyses gave as a mean : C = 33.9 ; S = 49.9 ; H = 0.9 ; 0 = 15.3 per cent. The substance reprecipitated from caustic potash also gave numbers which varied somewhat. It was found later that a separation of a Substance of constant composition could be effected by means of sodium carbonate. The deposit from the tubes was boiled with a solution of sodium carbonate, when the greater portion dissolved, giving a dark brown solution.This was separated by filtration and acidified with hydrochloric acid. The reddish-brown precipitate formed was collected, washed thoroughly, and dried at 100". After repeated digestion with carbon disulphide, the substance was kept at 110" until the weight was constant. I n the two analyses given, one sample was kept for a period of six months before digestion with carbon disulphide, whilst the other was treated immediately after preparation. (a) 0.1913 gave 0.2625 CO, and 0.0202 H,O. C = 37.4 ; H = 1.17. 0.2062 ,, 0.7362 BaSO,. S = 4904. (6) 0.2106 ,, 0.2898 CO, and 0.0219 H,O. C = 37.5 ; H = 1.15. 0.1843 ,, 0.649 BaSO,. S=48*4. C,,H,O,S, requires C = 37.06 ; S = 49.4 ; H = 1-16 ; 0 = 12.38 per cent. The small portion insoluble in sodium carbonate is almost completely dissolved by caustic soda.Analyses of the reprecipitated product from this solution did not give constant results, but in all cases the percentage of carbon was less and that of the sulphur more than in either the original deposit or the substance precipitated from sodium carbonate solution. Preparation of the Silver Cornpound. The substance obtained by reprecipitation from sodium carbonate was carefully purified from any free sulphur and then dissolved in caustic soda. The precipitate formed on acidifying with hydrochloric acid was collected, washed thoroughly with .distilled water, and then dissolved in a mixture of equal parts of ammonia (sp. gr. 0.88) and water. Silver nitrate solution, with which ammonia had been mixed until the precipitate which first formed redissolved, was now added, and the dark brown precipitate which formed was filtered off after some time and washed with a dilute solution of ammonia. The salt was then dried in a vacuum over sulphuric acid until the weight was constant.The silver was estimated by heating with nitric and hydrochloric acids in a sealed tube.LIBERATION OF TYROSINE DTJRING TRYPTIC PROTEOLYSI8. 145 0.1926 gave 0.1279 AgCl. 0.2820 ,, 0.1866 CO, and 0,0084 H,O. C = 18-04 ; H=0*32. C16H0,S8Ag, requires C = 1S.24 ; H = 0.09 ; Ag = 51.2 per cent. Ag = 50-01. Preparation of the Amzmonizcrn Compound. The substance obtained by precipitation from the alkaline solution was dissolved in equal parts of ammonia and water and evaporated in a vacuum over sulphuric acid. No crystals separated, but a brownish- black solid was left. This substance had no smell of ammonia and dissolved readily in water. On treatment with alkali, ammonia, was evolved. The solid ammonium compound on heating gave off ammonia and then decomposed into a yellow oil and a black solid, as was the case with the original deposit. These experiments lead to the conclusion that, in the slow com- bustion of carbon disulphide and oxygen, the reddish-brown substance deposited consists chiefly of a cornpound having the composition ClcH604S8, along with small quantities of another acid substance or substances containing less carbon and more sulphur, and also very small quantities of free carbon and sulphur. THE UNIVERSITY, N ANCHESTER.

ISSN:0368-1645    

DOI:10.1039/CT9068900142

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

LIBERATION OF TYROSINE DTJRING TRYPTIC PROTEOLYSI8. 145 XVIII.-The Liberation of Ty-osine during Tryptic Pro teol ysis. By ADRIAN JOHN BROWN and EDMUND THEODORE MILLAR. WHEN studying the various methods suggested for the purpose of measuring the activity of proteolytic enzymes, it occurred to us t h a t a method of directly estimating tyrosine by bromination recently described by James H. Millar (Trccns. Guinmss Reseamh Laboratory, 1903, 1, Part I) might fiimish a means of determining the course of proteolytic change in those cases i n which tyrosine is liberated during the breaking down of the protein molecule. An investigation in this direction was therefore commenced and the r e s u h so far obtained are described i n this paper. The paper may be summarised as follows : (1) J.H. Millar’s method of estimating tyrosine by bromination is applicable to the estimation of tyrosine in tho presence of proteins and their earlier cleavage products due to enzyme action, if suitable control{experiments are employed. VOL. LXXXIX. L146 BROWN AND MILLAR: THE LIBERATION OF (2) Tyrosine is nat a late product of tryptia proteolysis, as is usually supposed ; on the contrary, the tyrosine nuoleus of a protein is attacked and the whole of the tyrosine liberated during the first stage of tryptio digestion, (3) The resistance of the protein tyrosine nuoleue to peptic hydrolysis is confirmed. (4) Attention is called to the similarity of Emil Fiscber and E. Abderhalden’s recent observations on the actions of tryptic and peptic enzymes on polypeptides containing a tyrosine nucleus (Zeit.physiol, Chsrn., 1905,46, 52) to the authors’ observations on the aotions of the same enzymes on proteins containing a tyrosine nucleus. reliable means of differentiating enzymes of a peptic from those of a tryptic nature, and may assist in throwing some light on the confused state of knowledge with regard to the existence of a tyrosine nucleus in the dieerent albs- moses resulting from peptic and tryptic proteolysis. ( 5 ) The authors’ investigations appear to indicate EX P ERIM E N TA L. J. H. Millar’s method of directly estimating tyrosine (Zoc. cit.) i s based on its reaction with free bromine, by which a bromine compound of tyrosine is formed. Tyrosine is dissolved in hydrochloric acid to which potassium bromide is added.The solution is then titrated with a N/5 sodium bromate solution. The liberated bromine resulting from the interachion of t h e sodinm bromate a.nd bromide in acid solution is rapidly absorbed by the tyrosine present, and the end of the reaction determined by employing starch and potassium iodide as an indicator for free bromine. J. H. Millar’s experiments with pure tyrosine show that the reaction results in the formation of dibromotyrosine aacording to the following equation : C6H,(HO)*CH2*CH(NH,)*C02H + 4Br = C,H2Br2(HO)*CH2*CH(NH2)*C02H + 2HBr. The method of estimating tyrosine is shown by J. H. Millar to be applicable not only to the accurate estimation of the pure substance, but also to the substance when it exists in intermixture with ammonium salts and amides and amino-acids such as asparagine, aspartic acid, leucine, and phenylalanine, which result from complete acid proteolysis.J. EL Millar’s work does not, however, show whether his method is applicable to the determination of tyrosine in the presence of proteins or their primary cleavage products, such as albumoses or peptones ; itTYROSINE DURING TRYPTIC PROTEOLYSIS. 147 was necessary, therefore, for us to investigate this point as preliminary to an attempt to employ the method for the estimation of tyrosine when present among the products of enzyme proteolysis. Preliminary experiments with solutions of egg-albumin, edestin, and gelatin indi- cated that they possessed to some extent the property of absorbing bromine under the conditions employed by J.H. Millar to estimate tyrosine. Following on this observation, a solution of edestin was prepared and divided into two equal vclumes. One part was titrated direct with N/5 bromate solution and its power of absorbing bromine noted. A known amount of tyrosine was dissolved in the second volume and it was also titrated with broniate solution. It was then found, after correcting the result of the second titration for tho amount of bromine absorbed by the edestin alone, indicated by the first titration, that an accurate measure was obtained of the amount of tyrosine introduced. Similar results were also obtained when gelatin and egg- albumin mere employed in tbe place of edestin. Our preliminary experiments therefore showed that it was possible to determine tyrosine in the presence of proteins if control experiments were made in order to correct for the bromine absorbed by the proteins.A series of experiments were then made in which edestin* was digested with pancreatic extract and the products of change examined by the bromine method as follows : A 1 per cent. solution of edestin was prepared by dissolving 2 grams of the dry substance in 200 C.C. of a 0.5 per cent. sodium carbon- ate solution, 50 c.c of this solution being placed in each of four flasks. To each of three of these flasks, 5 C.C. of active pancreatic extract (Benger) were added, and to the fourth flask, employed as a control, 5 C.C. of pancreatic extracb were added which had been previously heated to looo to render it inactive. All the flasks were placed in a water-bath kept at 32'.After 24 hours, the control and the contents of one of the flasks containing active pancreatic extract were titrated with bromate solution after the addition of 20 C.C. of SO per cent. hydrochloric acid and 10 C.C. of a 20 per cent. solu- tion of sodium bromide; and after 72 and 144 hours respectively the contents of the second and third flasks containing active pancreatic extract were titrated in a similar manner. The results obtained are given in the following table : * Edestin was employed in this and many of the followiiig experiments, contains a tyrosine nucleus and can also be readily prepared in a comparatively state, as it pure148 BROWN AND MILLAR: THE LIBERATION OF N/5 - Bromate solution after Time of NiB-Bromate deducting digestion.solution used. control. Active digestion ... 24 hours 0.80 C.C. 0.38 C.C. Control ............ 24 ,, 0'42 ? 7 7 7 72 7 , 0.80 ), 0.38 ,, > I 0.80 ,, 0-38 ,, ,, 144 9 , - Calculated per cent. of tyrosine formed from edestin during proteolysis. 4'06 4-06 4 '06 - It appeared from the above experiments, if the method of estimating tyrosine adopted was reliable, that 4.06 per cent. of tyrosine resulted from the tryptic digestion of edestin during the periods of 24, 72, and 144 hours, Oh the supposition that proteolysis had pro- ceeded far enough during 24 hours-the shortest period employed-to liberate the whole of the tyrosine from its containing nucleus in the edestin molecule, the results appeared quite reasonable, but on other grounds they were open to question.I n the first place, it was questionable whether the small volumes of bromate solution consumed in the above experiments measured the tyrosine present with any approach to accuracy. It was found, however, on experimenting with known amounts of tyrosine, com- parable with those measured in the preceding experiments, that very accurate results were obtained considering the small volumes of bromtlte solution employed. A second more difEcult objection to meet questioned the accuracy of the correction obtained from the control experiment. The control indicated the amount of bromine absorbed by the pancreatic extract and the undigested protein, and was subtracted as a correction from the total amount of bromine absorbed by an intermixture of digested products and pancreatic extract in order to arrive at the amount of bromine absorbed by the tyrosine liberated.It was open to doubt whether the correction remained constant under these conditions. When solutions of edestin and pancreatic extract of similar concentration to those employed in the foregoing experiments were titrated separately, it was found that each absorbed bromine t o some extent.* For instance, when 0.5 gram of edestin and 2.5 C.C. of pancreatic extract were titrated separately with bromate solution, bromine equal to 0.3 C.C. of bromate solution was absorbed by the edestin and to 0.1 C.C. by the pancreatic extract. It was possible to digest pancreatic extract alone as a control in order to ascertain whether its original power of absorbing bromine underwent any change during digestion, and it was found on doing so that no alteration took place.The accuracy of the control experiment PO far as it concerned the pancreatic extract was therefore established. But with * Tyrosine has been fount1 in all pancreatic extracts examined.TYKOSINE DURING TRYPTIC PROTEOLYSIS. 149 regard to the part of the correction applying to the bromine absorbed by edestin previous to digestion, it still remained open to doubt whether it could be employed with accuracy after digestion had taker1 place and the edestin molecule had been broken down to a greater or less extent. There appeared to be no way of obtaining an answer to this question by means of experiments with the tryptic digestion products of edestin, but experiments with the tryptic digestion products of gelatin pointed to the conclusion that no change takes place.Gelatin, unlike a typical albumin or globulin, does not contain a tyrosine nucleus ; it appeared, therefore, that if an examination of its digestion products by the bromine method were made, the complicating presence of tyrosine would be avoided and some light might be thrown on the constancy of the control referred to above. A series of digestion experiments with a 1 per cent. solution of gelatin and pancreatic extract were made under similar conditions to those with edestin (p. 148) with the following result : 50 C.C. of gelatin solution and 2.5 C.C. pancreatic Time of ex tract. digestion. 1. Active digestion ... 48 hours 2- , Y 7 , 100 ,, 3. 7 9 > > 148 Y , 4.Control ... ... ... ... - Calculated HIS-Bromate percentage of solution used tyrosine formed N15-Bromate after deduction during solution used. of control. proteolysis. 0.35 C . C . none. none. 0-35 ,, 9 , ,$ 0.35 ), ,? , 9 0.35 ,, - - It will be seen from the foregoing results that the amounts of bromine absorbed by the different digestions of the gelatin do not vary from the amount originally absorbed by the gelatin prior to diges- tion, which shows that for gelatin at least the cleavage products of its molecule absorb the same amount of bromine as the original molecule prior to hydrolysis. It seemed probable, therefore, that the same conditions might obtain with edestin. More convincing evidence of this was, however, obtained by an examination of the products of a peptic digestion of edestin itself.There was good reason to anticipate from the results obtained by previous investigators that it would be found that the tyrosine nucleus of a protein such as edestin was not attacked during peptic digestion, and consequently that free tyrosine would not be present among the products of peptic proteolysis. On this assumption, the following experiment on the digestion of edestin by peptase was made: 3 grams of edestin were dissolved in 300 C.C. of a solution containing 0.27 per cent. hydrochloric acid, and 50 C.C. of liquor pepticus (Benger) were then added. Immediately after intermixture, 50 C.C. of the solution were vithdrawn and titrated with N/5 bromate solution in150 BROWN AND MlLLAR: THE LIBERATION OF order t o ascertain the amount of bromine absorbed by the original mixture of edestin and liquor pepticus prior to digestion.The rest of the solution was kept in a water-bath a t 32”, and during digestion portions were withdrawn and titrnted with bromate solution a t succes- sive intervals of time. The results obtained are given below : N/5-Bromate solution employed to titrate 50 C.C. of edestin solution. Control, prior t o conmencement of digestion ... 0.50 C.C. After 24 hours’ digestion .............................. 0.55 ,, ,) .............................. 0.50 ,, ) ) .............................. 0’60 ’, 8 ’ .............................. 0.55 ,, ) ) ............................. 0-55 ,, 9 , 48 9 , 9 , 72 , t 9 , 96 > Y >, 192 7 3 During the course of the prolonged peptic digestion of edestin in the above experiment, it will be noticed that-within errors of experi- ment-the original edestin and its digestion products absorbed equal amounts of bromine--a result markedly different from that which was obtained when digesting edestin with pancreatic extract.The experi- ment therefore confirmed the impression that tyrosine is not liberated during peptic digestion, and further strengthened the view that our method of employing a control for the bromine absorbed by proteins in digestion experiments was reliable. Before proceeding to make use of J. H. Millar’s bromine method for a further investigation of the conditions governing the liberation of tyrosine during tryptic proteolysis, it seemed desirable, however, to inquire as to the existence of another possible source of error.It i n known that tryptophane (scatoleaminoacetic acid) is very generally found among the products of proteolysis, and that it readily forms derivatives with free bromine. The presence of tryptophane was, moreover, recognised by us among the tryptic digestion products of edestin. It seemed possible, therefore, that the accuracy of the estimation of tyrosine by means of bromine might be influenced by the presence of tryptophane, although the results obtained in the experiments with edestin previously described appeared to render this unlikely. The investigations of 8. Vines indicate that tryptophane is liberated in gradually increasing quantities during tryptic proteolysis ; however, the amounts of bromine absorbed in our experiments with edestin (p.148) remained constant during digestion for very varying intervals of time, a result not likely t o be obtained if tryptophane takes part in absorbing the bromine. I n order, however, to settle this point definitely, tryptophane was prepared by Hopkins and Coles’ method (Sourn. Physiol., 1901, 27, 418), and subjected to the test of direct experiment. During protein digestion, tyrosine and tryptophane are said to beTYROSINE DURING TRYPTIC PROTEOLYSIS. 151 liberated in the approximate proportions of 4 : 1.5. In order, there- fore, to obtain conditions in some degree parallel with the digestion experiments with edestin (p l48), tyrosine and tryptophane in the proportion of 4 : l5-that is, 0.5 gram of tyrosine and 0.018 gram of tryptophane-were dissolved in 50 C.C.of water and titrated with bromate solution : bromine absorbed 2 0.9 C.C. N/5 bromate solution. A solution of 0.5 tyrosine alone in 50 C.C. of water was also titrated : bromine absorbed = 0.9 C.C. N/5 bromate solution. The experiments, therefore, indicated that no bropine was absorbed by the tryptophane employed. A second series of experiments in which more tryptophane was employed than in the foregoing series led to a similar conclusion. I n a further experiment in which 0.03'7 gram of tryptophane alone mas titrated with bromate solution, no bromine was absorbed.* As the evidence obtained from the experiments described above appeared t o show that the bromine method, when employed with a control, was capable of estimating tyrosine when present among the products of tryptic proteolysis, further experiments on the tryptic digestion of edestin were made.The first series of experiments with edestin (p. 148) indicated that the maximum amount of tyrosine was liberated within the first twenty- four hours of tryptic digestion, and this appeared to show that the tyroaine nucleus of the protein was attacked a t a much earlier stage of digestion than is usually supposed. Five hundred C.C. of a 1 per cent. solution of edestin, rendered alkaline by the addition of 2.5 grams of sodium carbonate, were digested with 25 C.C. of pancreatic extract (Benger) in the presence of a little toluene at 32'. A control experiment in which the pancreatic extract was rendered inactive by heat was also prepared, The following results were obtained : Percentage of tyrosine ht/5=Bromate calculated after solution used.deducting control. Active digestion after 30 minutes ... 0'8Q C.C. 2 *2 7 7 7 , )) 1 hour ...... 0'95 ) ) 8.8 7 7 Y 2 ,, If hours ... 0'90 ), 3.3 1 9 ,? > > 2 J 7 ..* Q'96 ,, 3.8 7 ) $ 3 7 9 20 7 1 * . * 0.95 ,, 3.8 - C011trol .................................... 0.80 ), The above experiments show that the tyrosine nucleus of the edestin was attacked during a very early stage of proteolysis. Although the digestion was carried on under conditions which did not favour very i+ The non-absorption of bromine by tryptophane under the conditions of J. H. Millar's method of estimating tyrosine is probably due to the hydrogen chloride which is present.152 BROWN AND MILLAR: THE LIBERATION OF rapid hydrolysis, within thirty minutes more than half the tyrosine was liberated, and within one hour the whole of it was set free.Other experiments with edeetio, which it is not considered necessary to describe in detail, also indicated that the whole of the contained tyrosine is liberated within a remarkably short period of time after digestion commences. Egg-albumin subjected to tryptic digestion under similar conditions to edestin also appeared to yield the whole of its tyrosine within three hours. From the above experiments with edestin and egg-albumin, it appeared, therefore, that the tyrosine nucleus of these proteins was one of the first constituent parts of their molecule to be attacked and hydrolysed during pancreatic digestion.As it appeared desirable to confirm the presence of tyrosine among the first products of tryptic digestion by some means other than the bromine one hitherto employed, 100 C.C. of a solution containing 1 gram of edestin and 0.5 gram of sodium carbonate were digested with 5 C.C. of pancreatic extract for one hour at 32' and a t once precipitated with trichloroacetic acid. The dense white precipitate of protein matter was filtered off and the filtrate evaporated to a small volume. After standing, crystals of tyrosine of characteristic appear- ance were obtained. Following on this, the crystals, together with the mother liquor, were titrated with sodium bromate solution, with the result that 4.3 per cent. of tyrosine, calculated on the original edestin employed, was found.I n a control experiment carried on under similar conditions to the above, but in which the pancreatic extract was rendered inactive by heat, no crystals of tyrosine were obtained. In a second experiment,25 grams of edestin dissolved in 2500 C.C. of 0.5 per cent. sodium carbonate solution were digested with 125 C.C. of pancreatic extract for forty-five minutes a t 32' and the digestion products precipitated with phosphotungstic acid in presence of dilute sulphuric acid. The precipitate was filtered off and the filtrate treated with barium hydroxide. The solution was again filtered to remove barium sulphate and the filtrate concentrated by evaporation to a small volume. On standing, tyrosine crystallised out freely. The tyrosine after separation was redissolved in dilute hydrochloric acid and again recrystallised from the solution after the addition of ammonium hydroxide.By this means, tyrosine was obtained in apparently a pure state. The above experiments therefore confirmed our original impression that the tyrosine nucleus of proteins is attacked and hydrolysed during a very early stage of tryptio digestion. An attempt was then made to gain some knowledge regarding the extent of protein degradation accompanying the breaking down of theTYROSJNE DURING TRYPTIC PROTEOLYSIS. 153 tyrosine nucleus and the liberation of tyrosine. A method employed by Weiss (Compt. rend. Tvccv. Laboratoh de Carhberg, 1903, 5, 11, 133) when investigating the proteolytic enzymes of germinating barley was used for this purpose.This investigator showed if a solution of a protein such as edestin is precipitated by tannic acid in the presence of sodium acetate, that almost the whole of the protein is thrown out of solution, and that the filtrate Contains a mere trace of nitrogen. If, on the other hand, the protein in solution is subjected to the action of a proteolytic enzyme previous to precipitation by tannic acid, varying amounts of the original protein nitrogen are found in solution, and the amounts found provide to some extent a measure of the proteolytic change which has taken place. As the primary cleavage products of proteolysis, such as albumoses and peptones, are precipitated by tannic acid, it appears from Weiss’s work that the soluble nitrogen found after proteolysis and precipitation with tannic acid is the nitrogen of arnino-acids and other substances of simpler constitution than albumoses or peptones.A solution containing approximately 2 per cent. of edestin and 0.5 per cent. of sodium carbonate was prepared : (1) A nitrogen determination by Kjeldahl’s method on 50 C.C. of the solution indicated that it contained 0.15 18 gram of nitrogen. (2) Fifty C.C. of the same solutim were digested with 5 c c . of pancreatic extract until a control digestion of the same volume of the extract showed by the bromine method of titration that the maximum quantity of tyrosine was liberated. The time taken for digestion t o this point was forty-five minutes. Digestion was then stopped by pre- cipibating the solution with tannic acid according to Weiss’s method.After filtration, i t was found that a volume of the filtrate equal to 50 C.C. of the original solution contained 0.0548 gram of nitrogen. (3) A control experiment, which is required when employing Weiss’s method, was made by digesting 50 C.C. of the original solution of edestin with 5 C.C. of pancreatic extract, the activity of which WAS previously destroyed by heat, and treating the solution in an exactly similar manner to Expt. 2. The nitrogen in 100 C.C. of the filtrate, equal to 50 C.C. of the original solution of edestin, was 0-0416 gram. This amount represents the nitrogen of the pancreatic extract employed which has not been precipitated by tannic acid, and also that of a very Rma31 amount oE edestin not precipitated by tannic acid.The total amount of nitrogen in the control experiment, 0.0416 gram, must therefore be subtracted from the total nitrogen found in Expt. 2 in order t o ascertain the amount of nitrogen which bas been rendered soluble during the digestion of the original edestin. The amount found was 0.01 32. The total amount of nitrogen in tbe edeotin present in 60 C.C. of the154 BROWN AND MILLAR: THE LIBERATIOX OF original solution was 0.1518 gram, therefore only 8.7 per cent. of this nitrogen was present in such form as to remain in solution unprecipi- tated by tannic acid after proteolytic digesticn had proceeded sufficiently to liberate the whole of the tyrosine. I n a second experi- ment with edestin, it was found that 9.1 per cent. of its contained nitrogen was rendered soluble.About one-third of the amount of soluble nitrogen found in the above experiments can be accounted for as being present in the tyrosine liberated ; the condition in which the remaining two-thirds exists is a t present unknown. The results of the above experiments should be regarded as only roughly indicating the maximum amoiin t of decomposition of edestin into substances not precipitated by tannic acid during the liberation of tyrosine ; it appears very probable that further investigation will show that the amount is less. However this may be, the experiments confirmed our previous conolusion that liberation of tyrosine takes place during the first stage of the tryptic hydrolysis of edestin. E. Fischer and E. Abderhalden have recently shown (Zoc.cit.), when synthetically prepared polypeptides containing a tyrosine nucleus are submitted to tryptia digestion, that they are hydrolysed and tyrosine is liberated. On the contrary, the same polypeptides are shown to resist the action of peptic digestion, and consequently no tyrosine is liberated. It appears interesting to compare these results with our observations on the actions of peptic and tryptic enzymes on proteins containing a tyrosine nucleus. Although the protein molecule is of far greater complexity than that of the polypeptides referred to, the behaviour of the two enzymes with regard to it has the appearance of being the same. This suggests that the tyrosine nucleus of both protein and polypeptide constitutes a point of attack for the tryptic enzyme.But, on the other hand, E. Fischer and E. Abderhalden (Zoc. cit.) show that some peptides which do not contain a tyrosine nucleus, such as alanyl- glycin, are hydrolysed by the tryptic enzyme, whilst others of some- what similar constitution, such as glycyl-alanin, are not decomposed. I n those cases in which hydrolysis takes place, i t cannot here be associated with a tyrosine nucleus, and it appears desirable t o bear this in mind when considering the mode of action of tryptase on the protein molecule. The liberation of tyrosine may be merely a secondary effect accompanying the cleavage of the molecule at some other point than the tyrosine nucleus. A reliable means of differentiating enzymes of a peptic from those of a tryptic nature is required, for attempted classification from the behaviour of these enzymes in acid or alkaline solution has proved iwu$cient, particularly with regard to vegetable proteolytic enzymes,TYROSINE DURING TRYPTIC PROTEOLYSIS. 155 It appears that the rapid arid complete liberation of tyrosine during tryptic digestion may furnish a satisfactory means of differentiating enzymes of a tryptic from those of a peptic nature. At present, the state of knowledge with regard to the existence of a tyrosine nucleus in the different albumoses resulting from tryptic and peptic proteolysis is in a somewhat confused state, and contradictory statements are frequently met with regarding t h i s question. From the results of our experiments, presumably no albumose resulting from tryptic digestion contains a tyrosine nucleus, since the whole of the tyrosine appears to be liberated in the free state in the earliest stage of digestion. On the other hand, one or more of the albumoses or other of the earlier cleavage products of peptic digestion should contain the whole of the protein tyrosine. A t present we have not experimented with a1 bumoses formed during tryptic digestion, but some preliminary experiments with a1 bumoses formed during peptic digestion indicate the presence of a, tyrosine nucleus in some and not in others. We have some reason t o believe that tyrosine is liberated from edestin during a very early stage of acid prot,eolysis as well as during tryptic pro t eol ysis. SCHOOL OF BREWING, UNIVERSITY OF BIRMINGEAM.

ISSN:0368-1645    

DOI:10.1039/CT9068900145

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

TYROSINE DURING TRYPTIC PROTEOLYSIS. 155 XIX.-Halogen Derivatives of Substituted Ozamides. By FREDERICK DANIEL CHATTAWAY and WILLIAM HENRY LEWIS. THE action of the halogens on substituted oxamides has been little studied, and the description of the substances formed is not satis- factory, inasmuch as the crude material was never subjected to any process of purification. By passing chlorine for different periods through a solution of oxanilide in boiling glacial acetic acid, Dyer and Mixter (Amer. Chem. S., 1886,8, 349) obtained two products : one, the melting point of which is not given, they regard as being possibly a trichloro-oxanilide; the other, melting at 2 5 5 O , they show to be some- what impure tetrachloro-oxanilide. I n the course of the authors’ study of substituted nitrogen chlorides, the action of chlorine on a boiling acetic acid solution of oxanilide has been investigated.I n this action, a mixture of chloro-oxanilides is formed from which it is difficult to isolate any pure substance in quantity, although both s-di-p-chloro- and 9-di-2 : 4-dichloro-oxanilides VOL. LXXXIX. &I156 CHATTAWAY AND LEWIS : can be separated in sufficient amount for identification. For purposes of comparison, these two compounds and some closely related deriv- atives have been prepared from pure specimens of the anilines. The symmetrical disubstituted oxanilides or the ethyl esters of the corresponding substituted oxanilic acids are formed almost quantita- tively when the substituted aniline is heated with ethyl oxalate, the product varying according as the aniline or the ethyl oxalate is present in excess. $JO*KH*C,H,Cl CO*NH*C,H,Cl CO*O*C,H, CO* NH*C6H,Cl + C6H4C1*NH, = I + C,H,*OH. Should the reaction yield a mixture of the two compounds, these can easily be separated from one another by dissolving out the oxanilic esters with alcohol, in which the disubstituted oxanilides are almost insoluble, When treated in alcoholic solution with ammonia, the oxanilic esters yield mono-substituted oxamides, thus : and when heated in alcoholic solution with the equivalent quantity of potassium hydroxide they yield the potassium salts of the substituted oxanilic acids, from which the acids are liberated on the addition of acetic acid : + C6H4C1*NH2.CO-OK + KOH = I FO-NH*C,H,Cl CO*NH*C,H,Cl CO NH*C6H,C1 If to a boiling glacial acetic acid solution of oxanilide a saturated solution of bleaching powder is added, a white solid is deposited consisting mainly of a mixture of s-dichloro-oxanilide and it's dichloro- amino-derivative.The latter can be separated easily owing to its ready solubility in chloroform. Unlike most nitrogen chlorides con- taining phenyl residues with both ortho-positions to the nitrogen unoccupied, it is transformed into the isomeric oxsnilide with the greatest difficulty, and its solution in acetic acid oan be boiled until the whole is hydrolysed with regeneration of s-di-p-chloro-oxanilide ; if any 9-2 :4-dichloro-oxanilide results, it is produced i n too small a quantity to be recognised. Related to this reaction is the circum- stance that if a saturated solution of bleaching powder is added to a boiling solution of s-2 : 4-dichloro-oxanilide in glacial acetic acid, the substituted oxamide is deposited from solution unchanged, no recog- aisable quantity of its chloroamino-derivative being formed.ThisHALOGEN DERIVATIVES OF SUBSTITUTED OXAMIDES. 157 behaviour is probably due to the hindrance offered to the addition of hypochlorous acid to the nitrogen by the spatial arrangement of the atoms forming the large molecule. It is less probable that it is due to the practical insolubility of the substituted oxanilides in even slightly diluted acetic acid. That symmetrically disubstituted oxamides containing groups of less complexity can readily yield nitrogen chlorides and bromides is shown by the behaviour of s-dimethyloxamide and s-diethyloxamide, which are readily converted by hypochlorous or hypobrornous acid into their s-dichloroamino- or o-dibromoamino-derivatives. s- Di- p-ch loropiLe*nylozodiciLlo~wotr.midc, C1~-\NC1*CO*CO*NC1~-\C1.\-/ \-/ Oxanilide is so slightly soluble in water that an aqueous solution of hypochlorous acid has practically no action on it, and its dichloro- amino-derivative has not up to the present been obtained. If to a solution of the anilide in boiling glacial acetic acid a saturated solution of bleaching powder is slowly added, a white solid is thrown out of solution, which consists of a mixture of s-di-p-chloro-oxanilide and its dichloroamino-derivative. If chloroform is added, the latter dissolves, and can be thus separated from the substituted anilide. To ensure complete conversion, the solution in chloroform is best shaken with a further quantity of bleaching powder solution acidified with acetic acid, and on separating the chloroform solution, drying, and evaporating off the solvent, the dichloroamino-derivative is left as a white, crystalline mass, which, after several crystallisations from a mixture of chloroform and petroleum, is obtained pure.It is readily soluble in boiling chloroform and sparingly so in petroleum; it crystallises from a mixture of the two in colourless, transparent rhombs (m. p. 169.). 0.3042 liberated I = 32.3 C.C. XI10 I. C1 as NC1= 18.82. C1,1LI,02N2C1, requires C1 as NC1= 18.76 per cent. It is a stable substance, which undergoes transfmmation very slowly, if at all.On heating for some hours with boiling glacial acetic acid, hypochlorous acid or chlorine is gradually given off and s-di-p-chloro- oxanilide regenerated. s-Di-p-chlorophenyloxodichloroamide can be prepared also in a similar manner from s-di-p-chloro-oxanilide itself.158 CHATTAWAY AND LEWIS : Ethyl p- Ch I oro- oxanilat el C1 /-\NH* CO*C02bC2H5. \-/ This compound is formed almost exclusively when ethyl oxalate (1 mol.) is heated to 180-200" for several hours with slightly less than the equivalent quantity (1 mol.) of p-chloroaniline. Ethyl alcohol is evolved and a clear, brown liquid obtained, which, on cooling, solidifies to a mass of crystals. On rubbing this to a paste with a little alcohol and pressing it on a porous plate, the ester is obtained as a white, soft, crystalline powder.It is moderately soluble in boil- ing alcohol, from which it crystallises well in thin, transparent, colour- less plates (m. p. 155"), which have a pearly appearance when pressed together. 0.1886 yielded 081212 AgC1. C1= 15.89. CloHloO,NC1 requires C1= 15.58 per cent.. p-Chloro-oxanikumide, Cl/-\NH-CO*CO-NH,. \-/ This compound, which is produced when a warm alcoholic solution of ethyl p-chloro-oxanilate is mixed with an alcoholic solution of ammonia, separates on cooling the liquid as a mass of fine needles and melts at 241"; it crystallisea from boiling alcohol, in which it is sparingly soluble, in small, colourless needles, which form a felted mass from which the mother liquor can only be removed by considerable pressure.0*1956 yielded 0,1435 AgC1. C1= 18.14. C,H702N2C1 requires C1= 17.85 per cent. s-Di-p-chloro-oxanilide, Cl*'-\NH* GO* CO *NH/-\Cl. \-/ \-/ This compound, which is produced when ethyl p-chloro-oxanilate is heated with p-chloroaniline, is most easily made by heating p-chloro- aniline in slight excess (2+ mols.) with ethyl oxalate (1 mol.) to 180-200° for three to four hours, the alcohol formed being allowed to escape. On cooling and extractin6 the crystalline mass repeatedly with boiling alcohol, the substituted oxanilide is left as a white, crys- talline residue, scarcely soluble in any ordinary solvent. It can with some difficulty be recrystallised from boiling glacial acetic acid, in which, however, it is only slightly soluble and from which it separates in glittering, four-sided, rhombic plates.The best solvent for this and similarly substituted oxamides is hot nitrobenzene, in which theyHALOGEN DERIVATIVES OF SUBSTITUTED OXAMIDES. 159 and oxanilide itself readily dissolve and from which they crystallise exceedingly well on cooling. The adhering nitrobenzene can be removed by boiling the crystals for a short time with alcohol. s-Di-p- chloro-oxanilide cryatallises from hot nitrobenzene in glittering, long, colourless, transparent, thin plates, which are probably much flattened rhombic prisms (m. p. 288'). 0.4583 yielded 0.4189 AgCI. C1= 22.60. C,,H,,,O,N,Cl, requires C1= 22.94 per cent. This compound can also be obtained by the direct chlorination of oxanilide dissolved in boiling glacial acetic acid, and is formed when s-di-p-chlorophenyloxodichloroamide is decomposed by a solution of hydrioclic acid or by boiling alcohol.This compound is prepared by heating 2 : 4-dichloroaniline (1 mol.) with rather more than the theoretical amount (1 mol.) of ethyl oxalnte at 180-200° for two to three hours. On adding a little alcohol to the hot product and cooling, the ester separates as a felted mass of white needles. These, after washing with a little alcohol, can be recrystallised from boiling alcohol, in which the oxamate is moderately soluble ; it crystallises from alcohol in colourless, transparent, long, hair-like crystals, seen under the microscope to be slender prisms (m. p. 1 1 9 O ) . 0.2318 yielded 0.2556 AgCl. C1= 27.26. C,,H,O,NCl, requires C1= 27.06 per cent.This compound separates as a mass of slender, white needles when a hot alcoholic solution of ethyl 2 : 4-dichloro-oxanilate is mixed with an alcoholic solution of ammonia. It is sparingly soluble in boiling alcohol, from which it crystallises as a network of colourless, branched, hair-like crystals (m. p. 234O). 0*1800 yielded 0.2228 AgCI. C1= 30.60. C,H,O,N,Cl, requires C1= 30.43 per cent.160 CHATTAWAY AND LEWIS : / -\ /-\ s-Bi-2 : 4-dichZoro-oxanilitZe, C1' \NH* CO*CO*NH( '(21. \--/ -/ c1 c1 This compound is produced when ethyl oxalate (1 mol.) is heated at 180-200"for three to four hours with a slight excess (2+ mols.) of 2 : 4-dichloroaniline. On cooling, a dark, semi-crystalline mass is left, from which s-di-2 : 4-dichloro-oxanilide is obtained as an insoluble crystalline powder on extracting with boiling alcohol.It is practically insoluble in all ordinary solvents, but can be recrystallised from boiling nitrobenzene, in which it is readily soluble, and from which it crystsllises in colourless, glittering, transparent, very slender, flattened prisms (m. p. 276O). 0.2512 yielded 0.3800 AgC1. C1= 37.40. C14H802N2C14 requires C1= 37.52 per cent. Action of Chlorine on OxaniZide.-It is not easy to obtain a pure product by the direct chlorination of oxanilide. If the latter compound is dissolved in a large excess of boiling glacial acetic acid and chlorine passed in to saturation, crystals resembling those of s-di-p-chloro- oxanilide separate on cooling. These are not pure, however, but contain some s-di-2 : 4-dichloro-oxanilide, and on repeatedly crystal- lising from nitrobenzene, the melting point of the substance, which a t first, as a rule, melted not very sharply at about 245", can be raised to about 280".On passing chlorine for a long time into a glacial acetic acid solution of oxanilide, a little Y-di-2 : 4-dichloro-oxanilide can be obtained, but the yield is poor and the process not a convenient one for preparing the compound. s-BimetlqZoxodicAloroamide, CH,~NCI*CO*CO*NCl~CH,. This compound is easily prepared by suspending finely-divided s-di- methyloxamide in a solution of hypochlorous acid made by adding potassium hydrogen carbonate in excess to a solution of sodium hypo- chlorite. On adding a little chloroform and shaking, the dichloro- amino-derivative is formed and dissolves in the chloroform.To ensure the complete conversion of the oxamide, the chloroform solution is again shaken with a fresh quantity oE hypochlorous acid. On separating the chloroform solution, drying with calcium chloride, and driving off the solvent, the dichloroamino-derivative is left as a very pale yellow liquid, which solidifies on cooling arid stirring with a little light petroleum. It forms a white, crystalline powder, easily soluble in light petroleum, from which i t can be crystallisedHALOGEN DERIVATIVES OF SUBSTITUTED OXAMIDES. 16 1 with some difficulty and from which it slowly separates in clusters of long, colourless, slender prisms (m. p. 37'). This substance and the other nitrogen chlorides described in this paper mere analyse'd in the usual way by titrating with thiosulphate the iodine liberated by a weighed amount dissolved in acetic acid and mixed with excess of a solution of potassium iodide. 0.4070 liberated I = 87.9 C.C.N/10 I. C1 as NC1= 38.28. C,H,O,N,Cl, requires C1 as NC1= 38.32 per cent. s-Die$hhyZoxodichZoronmide, C,H,*NCl*CO*CO*NCl*C2H,. This compound was prepared from s-diethgloxamide and isolated exactly as the compound previously described ; i t is a very pale yellow, viscid liquid, which, even after some months, shows no sign of crystal- lising. 0.4832 liberated I=91.2 C.C. N/lO I. On strongly heating, it decomposes with evolution of gas. C1 2s NC1=33*45. C,H,,O,N,Cl, requires C1 as NC1= 33.28 per cent. s-Dimethyloxodibromoamide, CH,*NBr*CO*CO*NBr*CH~. This was prepared from s-dimethyloxamide in the same manner as the corresponding chlorine compound, using a solution of hypobromous acid made from mercuric oxide and bromine. A little free mercuric oxide was added to the solution to prevent the development of free bromine, On filtering off the chloroform solution, drying, and expelling the solvent, the dibromoamino-derivative was left as a very pale yellow, crystalline mass. It crystallises well from chloroform in long, flattened prisms or plates of a very pale yellow colour (m. p. 95"). 0.3373 liberated I = 49.2 C.C. N/10 I. Br as NBr = 58.32. C,H,0,N,Br2 requires Br as NBr = 58.35 per cent. s-Diethyloxodibronzoamide, C,H,*NBr-CO*CO*NBr*C,H,. This compound was prepared from s-diethyloxamide and isolated exactly as the preceding compound ; it crystallises from chloroform in brilliant, glittering plates having a very pale yellow colour (m. p. €32.). Br as NBr = 53-66. C,H,,O,N,Br, requires Br as NBr = 52.94 per cent. 0.2794 liberated I = 36.S C.C. N/10 I. ST. BARTHOLOXEW'S HOSPITAL AND COLLEGE, LONDON, E.C.

ISSN:0368-1645    

DOI:10.1039/CT9068900155

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

162 BARLOW: THE OSMOTIC PRESSURE OF SOLUTIONS OF XX.-The Osmotic Pressure of SolutiorLs of Sugwr in Mixtuws of Ethyl Alcohol and Wa.ter. By PERCIVAL SMITH BARLOW. WHEN a copper ferrocyanide membrane is used with alcoholic solutions, no osmotic pressure is set up. This has been long known as the result of Tammann’s work (Ann. Php. Chem. Neue .FoZgc, 1888, 34, 309), and has been further confirmed by the author. Other work (Phil. Mag., 1905, [vi], 10, 1 ) has also shown that this membrane is very sensitive to the presence of water. These results, obtained almost simultaneously, suggested the inquiry as to how far the presence of alcohol might modify the osmotic pressure of an aqueous solution of sugar if the experiment was arranged so that there were equal concentrations of water and alcohol on opposite sides of the membrane.Cane sugar was used as the dissolved substance, since it is fairly soluble in a mixture of alc3hol and water, and, being the substance employed in Pfeffer’s experiments, which were the basis of the van’t Hoff “gas” theory, i t seemed the most suitable compound for the following work. Special conditions of experiment are employed. With the copper ferrocyanide membrane, the water of the solvent can aIone produce an osmotic current, and of the pure liquids is the one which alone dissolves the sugar. I n preparing for each experiment, the clean cell was soaked for from one to two days in the solvent, this (unless otherwise stated) being a mixture of equal volumes of ethyl alcohol (“ absolute ”) and water. The cell was then filled with the solution to be used in the experiment, and was again left for two or three days in the solvent.Fresh solution and solvent were used for the experiment itself. I n order to avoid as far as possible any osmotic pressure which might arise from any inequality in the liquids themselves apart from the dissolved sugar, the solvent was always prepared beforehand in large quantity. The same liquid could then be used for soaking the cell, for making tho solution, and for the outer liquid. Except in Experiment I, the cell stood in a glass bottle which was well corked. By means of a small mercury manometer through the cork, atmospheric pressure could be maintained above the outer liquid. Experiment I. Strength of solution, 0.0075 normal. Theoretical pressure, 128 mm.Initial pressure shown by the gauge was 39.5 mm. After ten days t h i s was 35 mm., and was followed by a steady fall. Experiment 11. Strength of solution, 0.01 17 normal. Theoretical pressure, 210 mm. After thirteen days the pressure was 6.8 mm. below atmospheric pressure. Initial pressure, 24 mm.SUGAR IN MlXTURES OF ETHYL ALCOHOL AND WATER. 163 This result indicates a small outflow. It may be due to greater concentration of water inside the cell, in spite of the precautions taken. The membrane is certainly sensitive to small differences of concentra- tion of water, but the difference in this case can only be very small, and should be more than counterbalanced by the sugar present. Experiment 111. Strength of solution, 0.027 normal. Theoretical pressure, 458 mni.After that time a rise in pressure of 9 mm. was shown. If one can assume steady values after so long a time, this experi- ment indicates that as the strength of the sugar soliltion increases, the possibility of the osmotic pressure being shown also increases, and that there is a strength of solution the osmotic pressure of which is nullified by the alcohol present. Solutions below this strength show no osmotic pressure. In Experiment IV, dextrose was the dissolved substance. The previous history of the cell used in this case is important, and is shortlyas follows. The cell was washed in several changes of freshly- boiled distilled water for nine days. It was then used with an aqueous solution of dextrose. The cell was closed and under pressure for eleven days. After that time, the outer water was examined for dextrose by Fehling’s solution; there was no reaction.Test cases showed that the solution was working well. This absence of sugar in the outer water is in agreement wit.h the general behaviour of a copper ferrocyanide membrane, but is important evidence when one considers the result of the following experiment. Finally, the cell was washed for twelve days in distilled water, and then used in the ordinary way with the mixed solvent. Experiment IT. Solution of dextrose : strength, 0.019 normal. Theoretical pressure, 325 mm. The cell was closed for five weeks and then showed a pressure of 6 mm. The outer liquid was examined for dextrose, and a small but distinct precipitate of copper oxide was obtained.The membrane, however, had been proved (as above) to be impermeable to dextrose under greater internal pressure; it therefore appears as though the membrane ceased to be impermeable t o the dextrose in the presence of alcohol. It will be necessary t o consider this part of the experiment later. The actual osmotic effect is seen to be in agreement with those of the first three experiments. Having found that, as the strengths of the solutions increased, the possibility of demonstrating the osmotic pressure also increased, it was natural to conclude t h a t the greatest osmotic effect would be shown with saturated solutions. Whatever theoretical considerations we may apply to the grouping of the different molecules in these solutions, it will be found that there should be a n inflow of water. If one The cell was closed for five weeks.164 BARLOW: THE OSMOTIC PRESSURE OF SOLUTIONS OF considers the two liquids as aqueous solutions of alcohol, the inner solution also contains dissolved sugar.This, on the generally accepted theory, will necessitate an inflow, given a suitable membrane. The osmotic current always tends to set up conditions which oppose it ; in this case, this opposition is twofold. There is the increase of internal pressure and the diminution in the concentration of the water outside. Hence, with saturated solutions of sugar in this solvent, no very large pressure can be expected. Excess of sugar was placed in the mixed solvent and left for three or four days, the mixture being shaken occasionally.Experiment V. Solvent, 3 vols. of water to 1 vol. of alcohol. Saturated solution of cane sugar. After eight days, the osmotic pres- sure was 164 mm. The cell was opened and closed several times; there was a steady rise in each case, showing altogether a large inflow. The gauge was an open one, and the highest pressure which could be shown on it was not large. Experiment VI. Saturated solution of cane sugar in equal volumes of alcohol and water. After eight days, the pressure was 62 mm.; after a month, it was 198 mm. Traube, as a result of his work on capillary constants of solutions (Phil. Mag., 1904, [vi], 8, 704), has put forward the theory that the osmotic current is caused by the difference of the surface tensions of the liquids separated by the membrane.I n another connection, I have had occasion to show how previous work bears on this theory (Phil. Mag., 1905, [vi], 10, 11). The theory seems to demand the passage of the whole liquid ; with a membrane of copper ferrocyanide, the current is caused by the water alone. The theory, therefore, does not include a simple case. Moreover, the surface-tension theory neglects the part played by the membrane, and therefore does not take into account all the conditions of work. I n considering the function of the membrane, the author’s work emphasises the importance of Nernsk’s researches on the absorptive action of the membrane. The part played by the membrane is itself a phenomenon of solution. One of the necessary conditions for an osmotic current is that the solvent (or one of the liquids) can be absorbed by the membrane.Traube further argues, on lines difficult to follow, that in the presence of alcohol the membrane may be rendered permeable to the sugar or dissolved substance, to which it is impermeable in aqueous solution. The latter part of Experiment IV is in favour of this view. This breaking down of the impermeability of the membrane t o sugar is especially difficult to understand in the light of the fact that the I n the following experiments, the solutions were saturated,SUGAR IN MIXTURES OF ETHYL ALCOHOL AND WATER. 165 cells remain sound for further use. This isolated case affords no basis for inference, but shows that the point is worthy of further examina- tion. I f this temporary permeability does occur, it is probable that the alcohol forms a true solution with the sugar. So far, the membrane used has been permeable to water only.Bladder is the only membrane known to the author which is permeable, in an osmotic sense, to alcohol and water ; this was used with a brass cell consisting of two parts fitted together by flanges and screws, the prepared bladder being fixed between the flanges and two india-rubber rings. With such a cell, a cane-sugar solution in equal volumes of alcohol and water (theoretical pressure = 1240 mm.), and far from being saturated, gave a rise in pressure of 140 mm. in five days, a rate of increase greater than that, in experiments with saturated solutions, even although bladder is imperfectly semipermeable. This result suggests that both parts of the solvent formed the osmotic current, as the previous knowledge of the membrane mould lead one t o expect.The selective action of the bladder would cause a larger inflow of water than of alcohol. The last case is where the membrane allows the alcohol only to form the osmotic current. Such a membrane is obbained with gutta-percha tissue. This was used in t.he same way as the bladder in the type of cell just described. Three cells were used for these experiments, but two, after considerable care and time, gave no result. There seems reason for thinking that this is due to deterioration of the membrane, and not to the solutions being too weak. The last experiment is thought to be of interest because of the length of time over which it extends. Solvent : equal volumes of alcohol and water.Strength of solution, 0.227 normal. Theoretical pressure = 3850 mm. Gutta-percha membrane. After being closed for two months, the osmotic pressure was 48 mm. I n this experiment, the movement of the gauge can be no indication of the volume of the liquid which has crossed the membrane; the outward sag of the membrane necessitates a greater inflow than the same gauge-movement would indicate in the case of a copper ferro- cyanide membrane. The ultimate object of osmotic research must be further knowledge of the internal conditions of solution. Incidentally there also arises the question of the cause of the current and the part played by the membrane. Previous reference to this makes further remark necessary. The cause of the current is found in the mutual potential energy of solution : that a current should flow depends on the a.bility of the membrane to dissolve the liquid.For mixed solvents, the liquid of the current depends on the selective action of the membrane. This Experiment VII. Alcohol is the inflowing liquid.166 THE OSMOTIC PRESSURE OF SUGAR SOLUTIONS. method of explanation, in addition t o being in agreement with experi- ment, brings osmotic phenomena into line with the principle that potential energy tends t o a minimum. On the matter of internal grouping of the molecules of the solution, not much can be said here. Recent work is all in support of ( c hydra- tion ” of the dissolved substance (whether ionised or not), and, more especially, work on non-aqueous solutions.It is still to be discovered why water dissolves sugar and alcohol does not, although one can quite truly say that there is some kind of attraction between sugar and water which does not exist between sugar and alcohol. I n this paper, the question arises as to whether the alcohol has some of this “ solution attraction ” for the sugar after t h i s has been brought into solution by the water. I n the light of the last experiment, it is probable that there is “ t r u e ” solution between the sugar and the alcohol. Here the osmotic current is one of alcohol, and in the usual osmotic sense the alcohol can be regarded as the solvent. If there is no true solution between the alcohol and the sugar, then the aggre- gation of the water and sugnr molecules causes a greater concentra- tion of free alcohol in the liquid containing the sugar than in the mixed solvent. Hence the flow of alcohol in the last experiment should have been outwards and not inwards. On the same assumption the van’t Hoff “gas” theory would give the same result. Experiment is therefore in favour of the “gas ” particles of the solution being aggregates of the three molecules: in other words, the sugar is “ hydrated ” by the water cmd the alcohol. The difficulties of finding the osmotic pressures of these solutions have been mentioned. The selective action of the membrane causes inequalities in the concentrations of the liquids themselves. This might be avoided by adopting a method of applying pressure from the outside (see Lord Berkeley’s paper, €‘roc. Roy. Soc., 1904, 73, 436)’ and so finishing the experiment before there could be any appreciable exchange of liquid. Without some such method, it appears to be futile to look for van’t Hoff values for mixed solvents and their solutions. These experiments were carried out at the Cavendish Laboratory ; and, in conclusion, the writer thanks Professor J. J. Thomson for the kindness shown to him during the progress of the work.

ISSN:0368-1645    

DOI:10.1039/CT9068900162

出版商:RSC    

年代:1906

数据来源: RSC