456 FRANKLAND AND TURNBULL: THE ACTION OF PHOSPHORUSXLIX.-The Action o f Phosphorus Pentuchloride on theOptically Active &Di- Esters o f G'lyceric Acid. -chloropopionates.By PERCY FARADAY FRANKLAND and ANDREW TURNBULL.THE experiments recorded in this communication were made somefifteen years ago, soon after the discovery of the "Walden In-version," and were undertaken with the view of furnishing furtherexamples of that transformation. Owing to circumstances we wereunable to complete the investigation, and the results have hithertoremained unpublished, although they have been referrid to inoutline by one of us (P. F. Frankland, Presidential Address, T.,1913, 103, 718).By acting on the methyl, ethyl, isobutyl, and heptyl esters of theactive glyceric acid of Frankland and Frew (T., 1891, 59, 96),which are all lzvorotatory, opticaITy active ap-dichloropropionateswere obtained, of which the methyl compound alone was dextro-rotatory, whilst the others were laevorotatory. The relationshipbetween the optical activity of the glycerates and the ap-dichloro-propionates to which they give rise, is seen from the followingtable :[ M y [MI:".Methyl glycerate - 5.76' -+ Methyl aB .dichloropropionate + 2.67'Ethyl 1 9 - 12.30 -+ Ethyl 7, - 3.06isoButyl ,, -23.05 -+ isoButyl 9 9 - 7.20Hepty1 9 9 -23.05 -+ Heptyl Y9 - 4.1PENTACHLORIDE ON TRE ESTERS OF GLYCERIC ACID.457That the difference in sign between the rotation of the methyl,on the one hand, and of the other afl-dichloropropionates on theother, indicates a difference in configuration between them respec-tively is prima facie highly improbable, whilst the identity of theirconfiguration is rendered alqiost certzin by the uniformity in thef 4=$ 20 & x- 2- 4- 6-8INFLUENCE .j T€MP€RATUREon theMOLECULAR ROTATION ofa( 8-D I C H LOR 0-PR OPI 0 N I CI I I L0" 20" 40" 60" 80" 101influence of temperature on their optical activity.Thus, from theaccompanying diagram, i t will be seen that, whilst rise of tempera-ture increases the dextrorotation of the methyl aS-dichloropro-pionate, it diminishes the 1;evorotation of the higher esters. If thelatter were of enantiomorphous configuration to the methyl ester,their laevorotation would doubtless be increased by rise of tempera-VOL. cv.H 458 FRANKLAND AND TURNBULL: THE ACTION OF PHOSPHORUSture. I n this connexion it may be mentioned that rise of tem-perature increases the lmmrotation of all the esters of glyceric acid(P. Frankland and MacGregor, T., 1894, 65, 760).On the other hand, i t is still a matter of uncertainty as t owhether the uj3-dichloropropionates have the same or the oppositeconfiguration t~ the glycerates from which they are obtained(P. Frankland, T., 1913, 103, 738).The actual figures given for the rotation of the ap-dichloropro-pionates must necessarily be accepted with reserve as we have noknowledge as t o whether, and if so, to what extent, racemisationhad taken place in the action of the phosphorus pentachloride onthe glyceric esters, which were themselves all employed in anoptically pure condition.I n preparing the afl-dichloropropionates there was alwaysobtained also a fraction of higher boiling point, which in the caseof the methyl and ethyl compounds deposited a white solid, melt-ing, after purification, a t 7 1 O and 3 6 O respectively. Analysis andmolecular-weight determination show that these producta aredoubtless of the type CH,C1*CC12*CC12*OR orCHCl,* CHCI*CCl,*OR,in which R is methyl, ethyl, isobutyl, and heptyl respectively.I n the case of the methyl compound the solid had the samemelting point, 71°, irrespectively of whether it wae obtained fromactive or inactive methyl glycerate.Both the solid methyl andethyl compounds were inactive; the liquid isobutyl and heptyicompounds were not examined for activity, being presumablyinactive also.The fact that these highly chlorinated compounds were inactivesuggests that the following may be the mechanism of their forma-tion from the afl-dichloropropionates :$!H,CII P'$!H,Cl R H2 vH,Ci CCI, -+ YHCl --+ $El -+C0,R C0,R C'C1 x:& \ORor or nrYHCI,SHCI VHCI, CHCl%HCO,Rp c 1CO,RI /CIc,-CI\ORThese compounds are obviously pentachloropropyl ethers.Com-pounds of a somewhat similar nature are already known; thusdichloro-oxalic ester, CCI,(OEt)-CO,Et, is obtained by the action ofphosphorus pentachloride on ethyl oxalate (Anschutz and StiepelPENTACHLORIDE ON THE ESTERS OF GLYCERIC ACID. 459Bey., 1895, 28, 61). Again, ethyl dichloro-oxalyl chloride,CCl,(OEt)~COCl, is obtained by the addition of oxygen to trichloro-vinyl ethyl ether, CC1,:CCl-OEt (AfinaLen, 1899, 308, 324 ;L.Henry, Rev. truv. cham., 1899, 18, 215).EXPERIMENTAL.Methyl ap-Dichloropropiomt e.Eighty-four grams of methyl glycerate (a, - 12*53O, I = 198-4mm.) were dissolved in 240 grams of chloroform, and slowlydropped through an inverted condenser into a flask containing200 grams of phosphorus pentachloride (292 grams are theoreticallyrequired) and 80 grams of chloroform. Some four hours wereoccupied in the addition of the ester to the phosphorus penta-chloride, aqd the mixture was then heated to boiling until thephosphorus pentachloride had dissolved, when a further quantityof 50 grams was added.On cooling, phosphorus pentachloridecrystallised out, and the liquid was poured off and the crystalswashed with chloroform, the washings being added to the liquid.The latter was now distilled free from chloroform under the ordin-ary pressure on the water-bath; the distillation was then continuedunder diminished pressure (100 mm.), the phosphoryl chloridepassing over at 55--60°. The residue was dissolved in chloroform,and returned to the flask containing the phosphorus pentachloridepreviously unacted on, together with a further quantity, themixture being again heated until evolution of hydrogen chlorideceased. The phosphoryl chloride was then again removed asdescribed above. This alternate treatment with phosphorus pent&chloride and removal of the phosphoryl chloride formed wasrepeated in all nine times, the total quantity of phosphorus penta-chloride used being 400 grams, of which 98 instead of the 108 gramsrequired by theory were recovered.The chloroform solution of the product, free from phosphorylchloride, was shaken with water and then with a solution of sodiumhydrogen carbonate, separated, dried with calcium chloride, freedfrom chloroform under normal, and then fractionated underdiminished, pressure until a product of constant rotation wasobtained.I n this manner 10 graxns of a colourless liquid, distillinga t 9Z0/50 mm. with the oil-bath a t 140°, were collected. I n thefractionation a white solid, described below, was also obtained.The liquid gave the following results in the Carius determina-tions of the chlorine :I.0.3969 required 0-8627 AgNO,. Cl= 45-39,0.3969 gave 0.7245 AgC1. C1= 45.13.H H 460 FRANKLAND AND TURNBULL: THE ACTION O F PHOSPHORUS11. 0.1897 required 0.4112 AgNO,. C1=45.26.0.1897 gave 0.3461 AgCl. C1=45*11.C,H,O,Cl, requires Cl= 45.22 per cent.The following density determinations were made :d 12°/40=1a3382; d 2Oo/4O= 1.3282; d 45'/4O=1*2947;a? 68'/4O= 1'2648.Rotation of Methyl ap-Dichloropropionate(obtained from lzvorotatory methyl glycerate).t. tlt0/4". a,. [a]". [MID.1=99-9 mm. :3.5O 1.3500 + 1.28O + 0.95" + 1-49'13.5 1.3365 1.96 1-47 2.3120.0 1.3282 2.26 1-70 2-6743.5 1.2975 3.04 2.35 3.6954.5 1.2825 3.26 2.54 3.99I n the first fractionation of the crude product obtained by theaction of phosphorus pen tachloride on methyl glycerate, the secondfraction, which had passed over a t 115-120°/20 mm.and theoil-bath a t 165O, was a white solid amounting to 14 grams. Thefraction before solidification exhibited a rotation of :a:'' -2'47O in a 99.9 mm. tube.On redistillation, 6 grams were obtained between 115O and 125O/15 mm. and bath a t 1 6 5 O . After spreading on a porous plate, thesolid melted a t 70-70'5O. It had a slightly acid reaction, so itwas dissolved in light petroleum and shaken with a solution ofsodium hydrogen carbonate, separated, and dried with calciumchloride. After allowing the petroleum to evaporate, the crystalsmelted at 71O. The light petroleum solution was inactive.This solid was in every respect identical with a solid similarlyobtained by the action of phosphorus pentachloride on inactivemethyl glycerate, which melted a t 71°, had a pleasant, camphor-likeodour, and separated from light petroleum in colourless plates.Itis also very soluble in alcohol, ether, chloroform, benzene, or glacialacetic acid. It is insoluble in water, and on adding silver nitrateto the mixture there is no change, but, on boiling, a white precipi-tate insduble in nitric acid at once separates:I. 0-2141 required 0.7370 AgNO,.11. 0.4419 required 1.5240 AgNO,.Lead chromate and silver foil were used in the following com-C1= 71-88.C1= 72-02.0.2141 gave 0.6179 AgCl. C1= 71.36.0.4419 gave 1.2801 AgC1. C1=71.63.bustions PENTACHLORIDE ON THE ESTERS OF GLYCERIC ACID.461I. 0.1578 gave 0.1115 CO, and 0.0320 H,O. C= 19.27; H=2*25.11. 0.1638 ,, 0.1167 CO, ,, 0.0360 H,O. C=19*43; H=2*44.C4H,0Cl, requires C = 19.47 ; H = 2.03 ; C1= 72.01 per cent.The following cryoscopic determinations of the molecular weightI. 0.5017, in 10.0 of benzene, gave A t = - 1.039'. M.W. = 236.6.were made in benzene solution:11. 0.7020, ,, 10.0 99 ,, At = - 1.453'. M.W. = 236.7.C4H,0Cl, requires M.W. = 246.5.The compound has, therefore, the formula :CH,Cl*CCI,*CCl,*O*CH, or CHCl,*CHCl*CCl,*O*CH,.Ethyl a fl-Dichloropopionat e.The preparation was carried out on essentially similar lines t othose above described for the methyl compound.Seventy-six grams of ethyl glycerate (a: - 22-73', I = 198.4 mm.)were exhaustively treated with phosphorus pentachloride.Sixteengrams of final product were obtained, boiling a t 110°/75 mm., batha t 150'I. 0.2825 required 0.5655 AgNO,.11. 0.2784 required 0.5579 AgNO,.C1=41*80.0.2825 gave 0.4754 AgC1. C1=41.62.C1= 41-86.0.2784 gave 0.4693 AgCI. C1= 41.69.The following density determinations were made :C,R,O,Cl, requires C1= 41-52 per cent.d 16'/4'=1'2554; d 20°/40=1.2505; d 42°/40=1.2228;d 57'14' = 1.2048.Rotation of Ethyl a fl-Dichloroprop'onat e(obtained from lzvorotatory ethyl glycerate).f. dt0/4". a,. [a]=* [ b11D.I =99-9 mm.1 2*0° 1.2600 - 2.47" - 1.96O - 3.35020.0 1.2500 - 2.23 - 1-79 - 3.0639.5 1.2260 - 1.71 - 1.40 - 2.3956.5 1.2050 - 1.17 - 0.97 - 1.66In the original fractionation of this ester the higher fractionswere dissolved in chloroform; the solution was shaken for fourhours with an aqueous solution of sodium hydrogen carbonate,separated, and dried with calcium chloride.On evaporating thechloroform 6 grams of a liquid, which crystallised on keeping, wereobtained. This was redistilled (boiling point 112-114O/ 12 mm.,bath a t 155O), and the distillate (4 grams) found to be inactive462 FRANKLAND AND TURNBULL: THE ACTION OF PHOSPHORUSAfter repeated crystallisation from light petroleum the constantmelting point, 36O, was obtained.I. 0.2028 required 0.6668 AgNO,.11. 0'2142 required 0.7002 AgNO,.C1= 68.66.C1= 68.26.0.2028 gave 0.5594 AgCI. C1= 68.21.0.2142 gave 0.5886 AgCl. C1= 67.95.H = 2.91.111.0.2263 ,, 0.1930 CO, and 0.0592 H20. C=23*26;IV. 0-2745 gave 0.2316 CO, and 0.0665 H,O. C=23.01;H = 2-69.C,H,OCl, requires C = 23.03 ; H = 2.69 ; C1= 68.14 per cent.CH2C1*CC1,*CC1,~O*C,H, or CHC1,*CHC1*CC1,*O*C2H,.The compound has therefore the formula :isoButyl ap-Dichloropropionate.Seventy-eight grams of isobutyl glycerate (a, - 16-58O,1 = 99.2 mm.) were similarly treated with an excess of phosphoruspentachloride in chloroform solution. By repeated fractionationof the product, 14 grams were ultimstely obtained (b. p. 127O/62mm., bath 182*), exhibiting a constant rotation:0.2246 gave 0.3299 AgC1. C1= 36.32.0.2727 gave 0.3981 AgC1. C1= 36.10.I. 0.2246 required 0.3928 AgN03.11. 0.2727 required 0.4731 AgNO,.C1= 36.52.C1= 36.23.111.0.2479 ,, 0.3789 CO, and 0-1342 H20. C=41*68;C7Hl2O,Cl2 requires C = 42-21 ; H = 6-03 ; C1= 35.68 per cent.The following density determinations were made :H = 6.01.d 16O/4O= 1.1619 ; d 2lo/4O= 1.1565 ; d 37*5'/4* = 1.1378 ;d 65O/4O= 1.1076.Rotation of isoButyl ap-Dichloropropionate(obtained from lzevorotatory isobutyl glycerate).t. dt"I4". a D. [QID. I If ID.1 =99*9 mm. :14.5' 1.1640 - 4.34" - 3.73" - 7-42'20.0 1.1580 -4.19 - 3.62 - 7.2040-5 1.1350 - 3-75 - 3.31 - 6.5968.0 1.1050 - 3.21 -2.91 - 5-79I n the preparation of this ester, again, a fraction of high boilingpoint was obtained (10 grams, 136-14Z0/19 mm., bath 1 8 5 O ) ; byfurther fractionation this was reduced t o 5 grams (b. p. 140°/20 mm., bath 191O). It was a viscid, colourless liquid with anodour resembling t h a t of aniseedPENTACHLORIDE ON THE ESTERS OF GLYCERIC AClD.463I. 0.2196 required 0.6431 AgNO,.11. 0.2258 required 0.6603 AgNO,.Cl= 61.16.C1= 61.06.0.2196 gave 0-5463 AgCI. C1= 61-52.0.2258 gave 0.5585 AgCl. C1=61.16.111. 0.2352 ,, 02531 CO, and 0.0820 H,O. C=29*34;C7H,,0C1, requires C = 29.12 ; H = 3.81 ; C1= 61.52 per cent.CH,C1*CC1,*CCl2*O*C,H, o r CHC1,-CHCI*CCl2*O*C4H,.H = 3.87.The compound has, therefore, the formula :Heptyl afl-Dichloropropionate.Seventy grams of heptylglycerate (aD - 11.75O, I = 100.45 mm.,t = 22O) were similarly treated with excess of phosphorus penta-chloride in chloroform solution. On subsequent distillation underdiminished pressure, a high and a low boiling fraction were ob-tained. The latter was refracjionated until of constant rotation,and 18 grams were obtained, boiling a t 144--148°/18 mm.,bath 186O:I. 0.2002 required 0'2790 AgNO,.11. 0.2102 required 0,2933 AgNO,.C1= 29.10.C1= 29-14,0.2002 gave 0.2379 AgCI. C1= 29.38.0-2102 gave 0.2480 AgCl. C1= 29.17.The following density determinations were made :CloH1,O,Cl2 requires C1= 29-46 per cent.d 13*5°/40=1*0960; d21°/40=1'0894; d 50°/40=1*0607;d 79'/4O= 1.0321.Rotation of Heptyl aS-Dichloropropionate(obtained from lzvorotatory heptyl glycerate).t. dt /4". an. [ale. [ 1 I I D .12.0° 1.0980 - 2.02O - 1-84' - 4.43OI = 99.9 mm. :20.0 1.0900 - 1.88 - 1.73 -4.1740.0 1.0710 - 1-73 - 1.62 - 3.9053.0 1-0580 - 1.63 - 1.54 - 3.7199.0 1.0230 - 1.29 - 1-26 - 3.04The fraction of high boiling point, on redistillation, passed overa t 153-154°/20 mm., bath 1 8 8 O ; it doubtless consisted of thecompound CH2C1*CCl,*CC1,*O*C7Hl, o r CHCl2*CRC1*CCl2*O*C7Hl5,but was not further examined.CHEMICAL LABORATORIES,UNIVERSITY, EDGBASTON, BIKMIKGHAY