ItESO1,UTION OF TE'l'RAHYDROPARATOI~UQUrNALDINE. 1093 THE ease with which 1r.evotetrahyclroq~iinnlciine ctm be separated from the externally compensated base by the w e of dextro-a-bromo- camphorsuiphonic acid (Pope aiid Pcachey, this vol., 11. 1 O M ) , suggested that interesting results might be obtained by applying the same method to Doebner and von Miller's externally compensated tetrahydropara- toluquinaldine (Re,*., 1583, 16, 2564) ; this base, which is described as being an oil at oidinary temperLttures, we find to be crystalline and to melt at 31-32O. When tt half molecnlur proportion of :Lmmoniuin dextro-a bromocsinphorsulphonate is added to a solution of one molecular proportion of racemic tetrahycli~op~ratoluquinaldine hychochloride, the hvo-base separates as the broruocamphorsulphonate, just as in the case of tetr~liy~l.oqiiinalcliue, autl this 1;evo-base melts a t 52-43'.This method, which is new in principle, should prove of service in similar cases and has already been applied to the prepara- tion of dextrotetrahydro-P-naphthylnmine (Proc., 1899, 15, 170). The crude dextro-base remaining in the mother liquors can be sub- sequently isolated as hydrochloride, 2nd from this salt the dextro-base may be separated in the pure state.1094 POPE AND RICH: I. LBVOTETRAHYDROPARATOLUQUINALDINE. On adding an aqueous solution of one inolecalar proportion of ammonium dex tro-a- bromocampb orsulplionat e to a war In, aqueous solution of two molecular proportions of racemic tetrahydropara- toluquinaldine hgdrochloricle, an oil sepmntes which solidifies to a crystalline mass as the solution cools.This crude lrcvotetmhydro- paratoluquinaldine clextro-a-bromocampliorsulphonnte is obtained as a mass of colourless ueeclles af t.er sever:d recrystallisations from hot dilute alcohol, It melts a t 195--196O, is moderately soluble in water or alcohol, and when dry is sparingly solul>le in acetone or ethylic acetate ; if a little nioisture is present, however, the soln- bility increases very considerably. The following analytical results were obtained with the salt dried ;it 100' : 0.1623 gave 0.3163 GO, 2nd 0.0957 II,O. 0.3561 ,, 0.1553 Aglh ttiitl 0.1932 EaSO,. BIB= 17.11 ; 8=6.59. C21H,o0,NBrS requires C: = 53.39 ; H = 6-31 ; Er = 16.95 ; 8 = 6.78 (1 =i 5:3*16 ; 13= 6.55. 0.2014 ,, 0.3'339 CO, ,, 0.1164 H,O.C=53*2 ; ll=6.3'7. per cent. On allowing its cold solution in a mixture of ethylic acetate and alcohol t o evaporntespontaneously, the s:tlt separates in large, colourless, transparent prisms (Fig. 1) belonging to the monosymmetric system ; 'I" the form ni100) is predominant and the prism p{110), although small, is usually the nest largest form present. The pinncoid c{OOlj is well-developed, whilst the Forms s * ( l O l j and ~'(101) are present only as narrow replacements ; the faces of the crystals are always more or less conchoidal in character and give very poor results on measurement. There is a perfect cleavage parallel to c(OO1) and the faces of the form a(1001 are striated parallel to the trace of the cleavage plane.RESOLUTION OF TETRAHYDROPARATOLUQUINALDIKE. 1095 Crystalline system.-Monosymmetric.a : b : c = 2.1766 : 1 : 1.2556. p = 78" 58'. Forms observed.-u( loo;, c lo01 ), p ( 11 O ) , Y( 101 ;, and y'(T01). The following angular measurements were olst:Liaed : Aiigle. f(T =loo : 101 ('?' =CJo1 : lo? (w'= 100 : _lo1 CY' =001 : 101 up = l o o : I10 11)) =110 : 110 pr =110: 101 yc =I10 : 001 p r ' = i i o : i o i Numbcr of observ:itioiis. 36 38 19 14 42 20 9 15 11 Limits. Mean. 51"5f' 27 1 cia 34 32 23 64 55 50 i 74 55 S5 26 80 57 Calculsteil. - - 6S031' 39 28 50 10 74 51 55 21 81 5 - The optic axial plane is the plane of symmetry and one optic axis emerges nearly normally tlirough a cleavage plrLte parallel to c(OO1) ; the other optic axis is seen t o emerge through cc(lOO), but not perpendicularly t o the face.The optic axial dispersion is slight ; the bisectrix emerging through u ( l O O ) is of positive sign and since this is the obtuse bisectrix the double refraction is negative in sign. After melting the substnnce on a inicroscope slide under a cover slip, i t crystallises with great reluctnnce from the edge of the prepara- tion i n long, flat, striated needles ; crystallisation is hastened con- siderably by alternate heating mid cooling. The optic axial plane lies across the longer dimension of the needles and the acute bisectrix sometimes emerges nearly normally to the plate ; the double refraction is negntive in sign. Usunlly one optic axis only can be seen emerg- ing through the needle and then the obtuse bisectrix of positive double refraction emerges in the microscope field.The crystalline film is thus crystnllogrnphically identical with the material deposited from solution. Carefully purified l~votetrahyd~oparntol~iquiiial~line destro-a-bromo- camphorsulphonate is dissolved in warm wnter and a slight excess of soda added, when the base separates as a colourless oil which solidifies completely on cooling ; the white, crystalline mass is collected on the pump, repeatedly \vilshed with cold water, and dried in a vacuum desic-1096 POPE AND ItICH: cator. On dissolving i t in petroleum boiling at 35-40’, and allodng the solution to evaporate spontaneously iu the air, lt~votetrahydropara- toluquinuldine separates in magnificent, lustrous, monosymmetric prisms (Fig. 3) several centimetres in length; i t melts at 55-53O.PIG. 2. F I G . 3. The crystals are enantiomorphously related to those of dextrotetra- hydroparatoluqninaldine, described Inter, and represented in Fig. 3 ; the forms (c(lOO], r ( l O l j , aud r’IlOT} are doniinant, sometimes the one and sometiines the other being the larger. Usually, the crystals are only conipleted at the one end, that, namely, on which the form o - (1 11) is developed ; the other end is frequently ragged or obliterated by an hour-glass shaped structure which groms from it into the cryst~l. Sometimes, however, the form b + (010f is present. Although the substance volatilises fairly rapidly in the air, yet the fuces give fairly satisfactory goniometrical results. Crystalline system.-Nonosymmetric : Hemimorpllic.(6 : b : c = 3.27-12 : 1 : 1-4339. Forms observed on 1% vote t ixhyd ropnra t oluquinald i ne. -a 100 >, Fornis observed on dost ro tetra11 ydroparn to1 uqnina1dine.-a ZOO 1, The following angular measurements were made on crystals of both r f I O 1 } , Y’(~OT), b + [OIO), and 0’-(1111. +M;, l y o i t , b - (ole), and O + 1111;. the h v o - and dextro-isomerides : n 11 g 1 c . Calc11ln ted. n/’ = 100 : 101 (w’ L 100 : l o i 1’”’ =lo1 : 101 (1.U =I00 : 111 01’ =A01 :101 OY’ = A1 1 : 101 00 =111:111 b/* =010 : 101 tbb =130 : 010 37 2s 35 16 32 14 16 12 15 G2‘14’-63‘3S’ G O 31 --TO 2 46 49-4; 36 77 36 -78 4’5 65 36 -66 42 5‘5 5s -53 36 i 2 58 - i 3 49 89 45 -90 21 89 40 -90 17 63” 3‘ 69 43 47 14 i 8 9 66 cj 53 16 73 21 90 3 90 1 - 69”43‘ 78 4 53 22 73 16 90 0 90 0 - -1lESOLUTION OF TETKAH YDROPU ATOLUQUIN ALDIN E.1097 I3cmene ............ Acetone ............ Chlorofonn. ....... Etliylic alcohol. ... The optic axial plane is the plane of symmetry and one optic axis is seen emerging through the face a( 100) ; the optic axial angle is large, and the optic axial dispersion slight. The double refraction is negative in sign and fairly strong. After melting on a microscope slide under a cover slip, the base solidifies readily from centres in long. needles, which extinguish parallel to the direction of growth; the optic axial plane is perpendicular to the direction of growth, and the optically positive bisectrix of a large optic axial augle emerges in the field. These long needles alternate with material showing aggregate polari- sation.This crystalline modification is identical with that deposited from petroleum solution. The following analytical results were obtained : 0.1148 gave 0.3439 CO, and 0.0979 H,O. C=81*69; H=9*48. 0.1258 ,, 0.3774 CO, ,, 0.1082 H,O. C = 8l*S3 ; H = 9-56. C!,,HI,N requires C = S1*98 ; H = 9.32 per cent. The specific rotatory power was determined in various solvents, and the results are stated in the following table : 21" O*:iOO2 25-3 - 3.20" . SO.9" - 130.2" - 130.3" 1s 0.5517 26.8 - 2.52 - 59.1 -95.2 -93.1 18 0'5013 25.25 -3.13 -78.8 -126.9 -155.4 1s 0'5329 25'2 - 2-56 -67.6 -1OY.!l -94.1 I I I I I I I In the last column of the ta..ble are given the molecular rotatory powers obtained by Pope and Peachey (this vol:, p. 11 16) for Izevotetra- hydroquinaldine in the various solvents used ; it is a very suggestive fact that the molecular rotatory power of the two homologous bases in benzene, acetone, and chloroform solution respectively are almost identical.Lsevotetrahydropariitoluquinaldiue is nearly odourless, and does not become coloured on exposure to light ; it is extremely soluble in the ordinary organic solvents, and was only obtained in good crystals from its solution in light petroleum. L~voleti.c~~?ldo~~~rnto Zuquinnldine li?/cl~ocl~ ZowXe, C,,H,,N,HCl+ H,O. A solution of the base in excess of warm hydrochloric acid deposits, on cooling, Itevotetrshydroparatoluquinaldine hydrochloride in minute, colourless, monohydrated crystals which become an hydrous at 100" and melt at 194-196". The anhydrous salt gave the following analytical results :1098 POPE AND RICH: 0.1146 gave 0,2803 CO, and 0.0850 H,O.C = 66.71 ; 13 = 8.24. 0.1954 ,, 0.3062 UO2 ,, 0.0937 H20. C -- 66.59 ; H = 8.30. 0.2531 ,, 0.1844 AgCl. C1= 18.04. CllHISN,HC1 requires C = 66.53 ; H = S.10 ; C1= 17.92 per cent. 1.6421 air-dried salt lost 0.1339 at 100". C,,~L3,,S,€ICl+ H,O requires H20 = S.35 per cent. A cold solution of the salt in hydrochloric acid deposits on spon- taneous evaporation large, highly lustrous, transparent crystals (Fig. 4) beloaging to the orthorhombic system and showing sphenoidal hemihedrism. FIG. 4. I . The crystals are onaiitiomorphoiisly related to those of dextrotetra- hydroparatoluquiiialdine hydrocliloride (Fig. 5). The piiiscoid b f 0 1 O ] is usually dominant, and the prism p ( l l 0 ) is the next largest form present.The pinncoids ccf100) and ~ ( 0 0 1 ; anti the dome ~ ( 1 0 1 ) are always small but well-developed ; the hemipyrnmid o + [ 1 11 is large, whilst the faces of the complementary form, w - (111) are present as minute, triangular replacements. The form y ( 0 l l} is always repre- sented by large, lustrous faces ; the crystals give very good results on measurement. Crystalline system-Orthorhombic. Sphenoidal hemihedrism. a : b : c = 0.S165 : 1 : 0.5703. Forms observed on crystals of lzevotetrahydroparatoluquinaldine hydrochloride.-n(lOO), b(010], c{OOl), p { l l O i , yfOl t i , ~1101f, o + (lll), and w - (111). Forms observed on crystals of dextrotetrahydropnratoluquinaldine hydrochloride.--o(lOO}, b10103, c[OOl), p [ l l O ; ., q[Oll), r(101), o - (1111, and LO -I- {lll).RESOLUTION OF TETRAHYDROPARATOLUQUINALDINE. 1099 The following angular measurements were made on crystals of both the laevo- and the dextro-isomeride : Angle. ap =loo : 110 p p =110 : 110 h(1 =010 : 011 ' q = O O l : 0 l l pq =011 : 011 i l d =loo : 001 co =001:111 2'0 =110 : 111 $10 =110 : 111 00 =111: 111 a0 = l o o : 111 nq = 1 1 1 : ~ 1 1 O l f i =I11 : 111 hf) =010 : 111 OW = 111 : iii bw = 010 : iii 0)' =111 : 101 itr = 100 : 101 bp =O?O : 1 l O Number of observations. 26 45 20 39 15 32 1 3 27 18 10 39 36 34 14 48 35 18 21 32 Limits. 3S942'-- 39O.10' 50 17 - 61 14 i S 0 - i S 59 59 49 - 60 41 29 li- 30 6 5s 41 - 59 47 S9 4 i - 90 15 41 39- 42 30 47 25- 4 s 1'2 131 49 -132 16 s 3 42 - 81 29 55 27- 59 0 30 58 - 31 33 62 7 - G2 51 64 32 - 65 12 49 44-- 50 31 114 38 -116 39 24 40- 25 27 54 51 - 55 19 BIean.39"13' 50 46 7s 27 60 15 29 43 59 20 90 0 42 3 47 56 132 1 81 6 58 45 31 15 62 29 64 56 30" 50 6 115 4 25 4 55 6 Calculated. 39'14' it3 2s 60 18 39 12 59 23 90 0 42 2 47 5s 132 2 84 5 58 45 31 15 62 29 50 7 115 3 25 3 55 4 - - After melting on a microscope slide, the anhydrous salt crystal- lises readily from centres whilst still hot in long, individual flakes enclosing long, penr-shaped, vacuous holes ; the flakes extinguish parallel to their direction of growth and crack across considerably during cooling. The pieces usually lie perpendicularly to the bisectrix of a large optic axial angle of positive double refraction; the optic axes emerge outside the microscope field.At the ordinary temperature, the substance solidifies very slowly to a finely grained inass showing aggregate polarisation. The following determinations of the rotation constants mere made : 0.5583 gram of the air-driecl salt, having the composition C,,H,,N,HCl+H,O, made up to 25.3 C.C. with watei. at '19', gave the value a, - 2*S6' in a 300 inm. tube, whence [ a ] , -64.7' and [1\1],- 139.7'. 0,4803 gi*am.of salt dried a t loo', having the composi- tion C,,H,,N,HC!l, made up to 35.2 C.C. with ivatIer at 19', gave the value a, - 2.69' in c?, 200 mm. tube, whence [ a ] , - 70.6' and [MID - 139.4'. The molecular rotatory power of lzevotetrahydroparatolu- quinaldine hydrochloride, namely, [MI, - 139 *5O, is considerably greater than that of lsvotetrahydroquinnldille hydrochloride, namely, [MI, - I2l*'i0 (compare Pope and Peachey, this vol., p.1072).1100 POPE AND RICH: ~e)LTo~ZIct:vbtetrcch?/~rol,nratoZuquinacldine, C,,H,,N* CO*C6H,. Ikevotetrahydroparatoluquinaldine hydrochloride is converted into i t s benzoyl derivative by agitation with warm soda and benzoic chloride ; the oily product crystallises on standing, and is purified by repeated crystallisation from hot acetone. It crystsllises in long, colourless needles melting at 100-101', and is fairly soluble in hot alcohol, acetone, 01- ethylic acetate ; attempts t o obtain crystals suit- able for goniometricnl nieasiireiiient mere uusuccessful. The following analytical results were obtained : 0.1926 gave 0.5746 CO, and 0.1 268 H,O.C: = 81 *40 ; H = 7.32. 0.1664 ,, 0.4964 CO, ,, 0.1102 H.,O. C=81.36; H=7.36. C,,H,,ON requires C = 81.51 ; 13 = 7.17 per cent. I t s specific rotatory power mas det,erminecl in a benzene solution containing 0.5150 grain in 25.1 C.C. at 18'; the rotatory power was found t o be ~ , + 9 * 3 9 " iu a 300 mm. tube, whence [ ~ ~ ] , + 2 2 9 ~ and [ XID + 606". Although the molecular rotatory power of benzoyl- lrevotetr~liydrop~~.;ltolucyuinttlclie, [ M],) + 606", is rather less than t h a t of benzoyll~votetriL!iyCiL'ocl~iinnldine, namely, [ 311, + 630", yet both derivatives of the lrero~otatory bases w e highly destrorot.itory ; the following table gives the molecular rotatory powers- [ 11 1, of the two sets of couipouncls : &Base in benzene.. ....................Hydrodiloriilc of I-base.. ............. 13enzoyl derivative of 7-Lasc ......... - 130'3" - 121.7 + 630 - 130.2" - 139.5 -t 606 11. DESTROTETRAHYDI~OPARATOLUQUINALDINE. The liquors remaining after t h e deposition of ltevotetraliydropara- toluquinaldine dextrobromocamphorsulphonate yielded a separation of dextro-base containing some of i t s limo-isomeride when treated with soda ; the base, with the addition of a molecular proportion of dextro- cainphorsulphouic acid, was dissolved in hot ethylic acetate, and on cooling a copious crystalline separation occurred. After several recrystallisations from boiling acetone, this materisl-dextrotetmhydro- prc~tolupinaldine dexts*ocanzpltomdphonate --was obtilined in colourless needles melting at 194-196". The salt is sparingly soluble in ethylic acetate or acetone but very soluble in water ; on treating i t s aqueous solution with soda, a product melting a t 37-40' was obtained,RESOLUTION OF T~TRAHYDROPARATOLUQUINALDINE. 1101 so that evidently it did not consist wholly of the dextro-base (com- pare Pope and Peachey, this vol., p.1078). Dextrotetrcch?lclroparatolzcpu.ilzctld~ne If'drochloride, CllHl,N,HC1 + H,O. The whole of the impure dextro-base was converted into hydro- chloride and the salt repeatedly crystallised from boiling acetone con- taining a little water; the solution was allowed to become super- saturated to a considerable extent, and crystallisation induced by scratching in order, if possible, to avoid the diaculty met with in isolating dextrotetrahydroquinaldine hydrochloride (this vol., p.1079). As the result of a series of crystallisations, pure dextrotetrahydro- paratoluquinaldine hydrochloride was o btsined as a colourless, crystal- line powder melting a t 194-196'. On spontaneous evaporation of its hydrochloric acid solution, the salt was obtained in large, sybenoidally hemihedral orthorhombic crystals, of which measurements are given above (p. 1098). The following analytical results were obtained with the anhydrous salt : 0.1335 gave 0.3261 CO, and 0.0988 H,O. C = 66.62 ; H = 8.22. 0,1248 ,, 0,3054 (20, ,, 0.0931 H,O. C = 66.73 ; H=S*29. 0.2709 ,, 0,1982 AgC1. C1=18*11. CllHl,N,HCl requires C = 66.53 ; H = 8.10 ; C1= 17.92 per cent. 1.7730 air-dried salt lost 0.1500 H,O a t 100". C,,H,,N,HCl+ H,O requires H,O = 8.35 per cent.The value aD+2*86" was observed in a 200 mm. tube with an aqueous solution containing 0,5125 gram of the anhydrous salt in 25.2 C.C. at 18', whence [.ID +70*3' and [ h f ] D +138.9', numbers agreeing closely with those obtained for the optical antipodes. Dextrot e tmh ylthoprat o h i quina Zclhae, C, H,,N. On adding soda to an aqueous solution of the hydrochloride, the base separates as an oil which immediately solidifies to a white, crystal- line mass; when crystallised by the spontaneous evaporation of its solution in light petroleum boiling at 20-503, i t is obtained in hemimorphic, monosymmetric prisms melting at 52-53', of which goniometric measurements are given above (p. 1096). The following analytical results were obtained : 0.1168 gave 0.3503 CO, and 0*1030 H,O.C = 81.80 ; H= 9.70. 0.1236 ,, 0.3701 CO, ,, 0.1074 H,O. C= 81.66 ; H = 9.66. CllHl,N requires C! = Sl.98 ; H = 9.32 per cent. VOL. LXXV 4 E1102 POPE AND RlCB! A solution of 0.4924 gram, made up to 25*3 C.C. with bengene at 19', gave ~ , + 3 * 1 4 ' in a 200 mm. tube, whence [ ~ ] ~ + 8 0 * 7 ' and [ R.l 1, + 129.9' ; the corresponding nuubers obtained for the laaw- rotatory base were [a], - 80.9' and [ MI, - 130.2'. INACT~VE TETRAIIYDROPARATOLUQUINALDINE. Externally compensated tetrahydroparatoluquinaldine was described by Doebner and von JIiller (Uer., 1883, 16, 2464) as an almost colourless oil, but we found, on treating its hydrochloride with soda in aqueous solution, that it separates as a colourless oil which readily solidifies a t the ordinary temperature and is but slightly liable to superfusion; it would seem therefore that Doebner and von Miller never obtained the base in a pure state, After purification by crystallisation from light petroleum boiling at 25-30', the base is obtained as ft white, granular, crystalline mass, melting at 31-32', The following analytical results were obtained : 0.1203 gave 0.3602 CO, and 0.1042 H,O.C-S1.65; H=9*63. 0.1189 ,, 0.3563 CO, ,, 0.1024 II,O. C=81*72; H=9*57, CllHl,N requires C = 81.98 ; H = 9-32 per cent. The base could not be obtained in measurable crystals by crystallisa- tion from any of the ordinary organic solvents; it is distinctly more soluble in light petroleum than are its active components. After melting on 9 microscope slide, it solidifies readily in six-sided, mono- Rymmetric plates, the top face being n(100); the forms c{OOl) and 9{011) are also present.The plane angle 011 : 011 is about 112O, the optic axial plane is the plane of symmetry, and the positive bisectrix and one optic axis emerge through cc( 100). This similarity between the crystalline forms of the active and inactive bases, and the greater solubility of the latter in light petroleum, suggest that the externally compensated base is either pseudoracemic or a mere mixture of the two antipodes j this question will be subsequently investigated, Rcccemic Tetrcclk ydyopumto Zu qui22cilclbie IIgdroch lor ide, C,,H,,N, HC1. After reducing paratoluquinnldine by Doebner and von Miller's method, racemic tetrah yd~oparatoluqninnldine hydrochloride is obtained as a white, crystalline powder which, after crystallisation from alcohol, melts a t 180--1-S3', and unlike the optically active hydrochlorides is anhydrous.On analysis, the following results.were obtained : 0.1147 gave 0*280S CO, and 0'0863 H,O. C = 66T7; €€= 8.36, 0.1193 ,, 0.291'7 CO, ,, 0.0886 H,O. Ca66.68; H=8*26. 0'2613 ,, 0.1907 AgCI, C1= 18.07. C,,H,,N,HCL requires C = 66.83 j H = 8e10 j C1= 1792 per ceut,RESOLUTION OF TETRAHYDROPARAT0LUQU"ALDINE. 1103 It is very soluble in water, less so in alcohol, and only sparingly soluble in boiling acetone. On spontaneous evaporation of its solution in dilute hydrochloric acid, it separates in large, colourless, transparent, mono- symmetric prisms of calcite-like lustre (Fig. 6). The pyramid w(il1) is usually dominant, and the pinacoid c{OOl} is well developed ; the forms FIG.6. o { l l l f and p(810) are generally small, but their faces give good results on measurement. The extinction in w l r l l } makes about an angle of loo with the edge cw, and there is a perfect cleavage parallel to w{ll l } ; the bisectrix of negative double refraction and one optic axis are observed to emerge through a cleavage plate, so that the plane of symmetry is the optic axial plane. Crystalline system-llonosymnietric, a : b : c = 1.4140 : 1 : 1*0601, p= S1° 5'. Poi-mu observed.-c(001), p { 2 l O ) , o{lll}, wC111). The folloming angular measiirements were obtained : Angle. co =001: 111 010 =111 :I11 cw = 0 0 1 : 1 g pp =210:210 cp = 0 0 ~ : 2 1 0 cp =001:210 pzo =210 : 111 00 =111:111 w z ~ = i i 1 : ii1 'LL'w=111: 111 Number of 111 easareIllL!ll ts.26 29 48 38 44 36 8 16 19 14 Limits. 43"46'--60' 1' 74 57 -76 14 54 46-5G 0 69 27-70 13 82 16-83 27 96 45-98 5 44 56-45 59 75 38 -i7 42 33 45-85 17 94 37-96 1 hlean. 49'24' 75 48 55 26 69 52 82 42 97 29 45 33 76 31 s4 36 95 27 Calculated. 49"68' 75 36 - - - 97 18 45 44 76 2 84 30 95 30 After melting on a microscope slide, the raceuic hydrochloride solidifies more readily a t the ordinary temperature than its active com- ponents. It solidifies quite readily whilst hot from centres in long needles containing irregularly -shaped vacuous bubbles. Many of the 4 E 21104 RESOLUTION OF TETRAIlYDROPARATOLUQU~NALDIN~. fragments are of the same shape as cleavage flakes of the crystals deposited from solution, and exhibit identical optical properties ; it is therefore proved that the molten mass solidifies 8s a racemic compound.Racensic ~e?~xo?lltetrul~?l~ro~arcctoluquinucltline, C,,H,,N* COO C,H,. On treating the racemic hydrochloride with soda and benzoic chloride, the benzoyl derivative is obtained with ease, and after recrystallisntion from acetone forms long, colourless needles melting at 103-10d0 ; i t is sparingly soluble in cold alcohol, acetone, or ethylic acetate, but fairly readily soluble in the hot solvents. The following analytical results mere obtained : 0.1886 gave 0.3S48 CO, arid 0.0852 H,O. C = 51-47 ; 13 = 7.36. 0.1339 ,, 0.3994 CO, ,, 0.0877 H,O. C = 81.35 ; H= 7.25. C,,II,,ON requires C = Sl.51 ; XI= 7-17 per cent. On spontaneous evaporation of its solution in acetone, the benzoyl derivative is deposited in large, colourless, transparent, monosymmetric prisms (Fig. 7 ) ; the yinacoicl 6{010) is dominant, and the form Fro. 7. Since none but pinacoid forms were ] is the smallest present. observed, the axial r;itioa could not be determined ; all the faces are of conchoidal character, so that the measurements are not very good. Crystalline system.-Moiiosyrnmetric. a : b : c = l p = S4" 11'. Forms observed.-cc{lOO], b[O10), and cfOOl). The following angular measurements were obtained : Nuinber of Angle. ~ observations. ~ ae=100 : 001 crb=lOO : 010 Be = 010 : 001 2 4 18 21 82"1i'-86"20' SS 29-91 55 90"O' SS 40-91 16POPE : RESOLUTION OF RACEMIC CAMPHOROXIBlE. 1105 There is a perfect cleavage on cc{lOO) and the extinction in 6(010) makes about 1 5 O with the edge a b . The optic axial plano is per- pendicular to the plane of symmetry, and the acute optic axial bisectrix emerges through c{OOl) ; the optic axial angle is fairly large, and the angle for blue is greater than that for red light. Our thanks are due t o the Governnient Grant Fund Committee of the Royal Society and to the Research Fund Committee of the Chemical Society for grants enabling the purchase of apparatus and material used in this work. GOLDSMITHS' I,I'RTITUTE, NEW C11OSS, S.E.