STEREOCHEIHSTRY.ALL substances exhibiting optical activity in solution which havehitherto been prepared are known t o contain one or more asymmetricatoms and it is customary t o attribute the optical activity to the pre-sence in the molecule of the asymmetric atom. It has, however,gradually become realised that the optical activity is a direct result ofthe enantiomorphous configuration of the molecule and that the latteris determined by the presence of the asymmetric atom ; it is possibleto write numerous constitutional formulae in which asymmetry is notassociated with any component atom but which, interpreted in accordancewith the tetrahedrsl configuration of methane, actually representenantiomorphous molecular configurations. Thus, in the acid of thefollowing constitution,i t must be supposed that the bonds in the hexaniethylene ring all liein one plane, that of the paper, and that the bonds attaching the groupsH and CO,H t o that ethylenic carbon atom not in the ring also lie inthe same plane.The bonds holding the H and CH, groups to thecarbon atom in the para-position to the ethylene group must, however,lie in a plane at right angles to the first and therefore perpendicular tothe paper and consequently the configuration represented must be anenantiomorphous one. No case of this kind mas known until thepresent year, when W. Marckmald and R. Meth prepared an acid towhich they assign the above constitution and resolved it into itsoptically active components by crystallisation with cinchonine ; theythus obtained the dl-4-methylcyclohexylidene-1-acetic acid with a speciticrotatory power of [a],, + 1 6 O .1 Subsequent to this, W. 11. Perkin, jun.,and W. J. Pope2 state that they have prepared an acid to which theyassign the above constitution and have been for some time endeavouringto resolve it ; their acid is different from that of Marckwald and Meth,and for the latter they suggest the following constitution :Bw., 1906, 39, 1171 and 6404. Proc., 1906, 22, 107186 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Marckwald and Meth quote reasons 1 supporting the constitutionwhich they originally assigned to their acid, and conclude that the acidof Perkin and Pope is the one which contains the double bond in theclosed ring. I n the event of Marckwald and Meth's view provingcorrect, their results must be regarded as marking a distinct advance instereochemistry, in that they furnish the first case of a substancepossessing optical activity in consequence of enantiomorphousmolecular configuration not due to the presence of an asymmetricatom.E. Erlenmeyer has continued his previous work on the stereoisomericcinnamic acids, C,H,*CH:CH*CO,H, and finds 3 that from alcoholic solu-tion three different brucine salts of synthetic cinnamic acid can beseparated ; these melt at 1 3 5 O , 11 3O, and 107" respectively.Cinnamicacid from storax is less soluble in alcohol than the former and gives onlythe brucine salt melting at 135' ; this salt is practically inactive whilstthe others are strongly laevorotatory in alcoholic solution.Erlenmeyertherefore suggests that cinnamic acid from storax is only one of the com-ponents of synthetic cinnamic acid, and supports this contention byquoting results obtained by crystallising cinnamic acid from the twosources with d- and Z-isodiphenyloxyethylamine. The further investi-gation of these substances and their crystallographic examination hasled Erlenmeyer and Barkow 4 to conclude that the following six iso-meric cinnamic acids must be regarded as distinct substances : (1)Erlenmeyer, sen.'s, isocinnamic acid, m. p. 37-38' ; (2) allocinnamicacid, m. p. 68"; (3) Liebermann's isocinnamic acid, m. p. 5 9 O ; (4)anorthic cinnamic acid, m. p. 80' ; (5) a-cinnamic acid, m. p. 134-135' ;(6) p-cinnamic acid, m. p.132-1 33'. The isocinnamic acid containedin the most soluble of the brucine salts, which differs slightly in crystal-line form from Liebermann's acid, and the synthetic acid apparently Con-stitute two more isomerides. Erlenmeyer's conclusions have beencriticised very adversely by W. Marckwald and R. Meth; theseauthors show that the salt melting at 11 3' contains alcohol of crystal-lisation and that the salt melting at 135" contains two molecules ofcinnamic acid to each one of brucine. They also point out that on dis-solving equivalent quantities of synthetic and natural cinnamic acidand brucine in alcohol, the solutions have the same rotatory power.They therefore conclude that the experimental evidence does not justifythe conclusions of Erlenmeyer.The view that mineral oil originates from the bacterial decompos-tion of proteins is put forward by C.Neuberg and supported by the1 Ber., 1906, 39, 2035.3 Ber., 1906, 39, 285.5 Ibid., 1177, 1966, and 2598.2 A m . Report, 1905, 168.4 r b i d . , m o .Biochem. Zeit., 1906, 1, 368STEREOCHEMISTRY. 187similarities between the optically active acids of petroleum and thoseobtained by the putrefaction of cheese, gelatin, &c. Vegetable lipasewas found to liberate d-dibromostearic acid and a dextrorotatoryglyceride from dI-dibromostearic triglyceride, showing that unorganisedferments are capable of producing optically active substances from in-active fats.E. Fischerl has contributed in the connected form of a lecture avaluable digest of his chemical investigation of the amino-acids,polypeptides, and proteins, in which the stereochemical relations ofthese substances are fully considered.a-Bromoisohexoic acid has been resolved into its optically activecomponents by E.Fischer and H. Carlj2 the method employed being thecrystallisation of the mixed brucine salts ; the lavorotatory acid yieldsd-leucine ( [ u ] ~ - 14-20') with ammonia. a-Bromo-/I-phenylpropionicacid, C6H5*CH2*CHBr* CO,H, has also been resolved by crystallisationwith brucine and quinine ; the kevorotatory acid gives d-phenyl-alanine, C,H,*CH,*CH(NH,)*CO,H, ([.ID + 31 T8') with ammonia.Fischer also describes convenient methods for preparing d- andE-leucines, and for converting these amino-acids into derivatives ofd-a-bromoisohexoic acid.H e has resolved synthetic a-aminoiso-valeric acid into its optically active components by crystallising itformy1 derivative with brucine ; the compound of the I-acid crystal-lises as the less soluble product. Fischer gives the name valine tothe acid and identifies d-valine with the active aminovaleric acid,(cH,),CH*CH(NH, j*CO,H, separated from lupins, horn, and casein ;d-valine has a bitter taste, whilst the I-isomeride, which has not yetbeen found in nature, possesses a pronounced sweet flavour. Thisdistinction between the taste of two enantiomorphously related iso-merides is similar to that observed in the case of the leucines andasparagines.E. Fischer and W. A. Jacobs have resolved externally compensatedp-nitrobenzoyl-dl-serine, OH*CH2*CH(C0,H)*NH*CO*C,H4*N0,, bycrystallisation with quinine ; the salt of the d-acid separates first andthe E-acid remaining in the mother liquors is conveniently purified bycrystallisation with brucine.The d-and I-serine,OH*CH,*CH(NH,)-CO,H,prepared by hydrolysing the nitrobenzoyl derivatives, differ in taste,the former being thesweeter; the I-serine is identical with the serineisolated from silk. isoserine, NH,* CH,*CH(OH)*CO,H, and diamino-propionic acid have been also resolved by crystallising their benzoylderivatives with optically active bases.C. Neuberg and E. Ascher resolve up-diaminopropionic acid,Ber., 1906, 39, 530. Ibid., 3996. Ibid., 2893.Bid., 2320. Ibid., 2943.Biochem. Zeit., 1906, 1, 380188 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.NH,*CH,*CH(NH,)*CO,H, by crystallisation with d-camphorsul-phonic acid ; the salt of a d-rotatory acid is thus first separated but, asit is donvertible into Z-glyceric acid by the action of nitrous acid,it must be termed Z-ap-diaminopropionic acid.An improvement of Warburg and Fischer’s method 1 of resolvinga-bromopropionic acid, CH,*CHBr *CO,H, has been dsvised byL. Ramberg;, the dZ-acid is frozen out from the acid which has beenpartially resolved by cry stallisation with cinchonine.dl-Aminobenzylidene-/3-naphthol has been resolved by M. Betti 3 bycrystallisation with d-tartaric acid ; the salt, dBdA, separates inalniost theoretical yield as the more sparingly soluble salt,J.C. Irvine4 contributes a simple method for the separation ofi-lactic acid from the dZ-acid by cry stallisation with morphine ; mor-phine Z-lactate crystallises readily from the mixed solution, and fromthe mother liquor the d-isomeride can be conveniently separated as thezinc salt.use Z-menthylcarbamide forthe purpose OF resolving externally compensated hydroxy-compoundsinto their optically active components; the method can be appliedeither by directly combining the carbimide and the hydroxy .com-pound, or by first converting the latter into a chlorocarbonic ester andthen condensing with Z-menthylamine. On applying the method todZ-~-phenyl-u’-4-hydro~yphenylethane, p-HO*C,H;CHMePh, d-a-phenyl-a’-4-hydroxyphenylethane Z-menthylcarbamate,C,,H,,NH*CO,.C,H,.CHMePh,is obtained as the less soluble product and, on hydrolysis with soda,yields the optically active hy droxy-compound.have resolved tetrahydro-l-naphthoicR.H. Pickard and W. 0. LittleburyR. H. Pickard and J. Yatesacid, CGKI<CH(CO,H) CH2-CH2>CH2, ([MID 2 1 *lo), and tetrahydro-2-naphthoic([MI,, 90.5’) into their optically active CH,*YH,CH,*CH*CO,H’ acid, C,H,<components by crystallisation with Z-menthylamine ; in each case thesalt ZBZA separates as the least soluble component. The molecularrotatory powers of the acid ions, stated in brackets above, are muchsmaller than that of the A2 (Or ’)-dihydro-l -naphthoic acid,CH(CO,H)-EH ,CH(C02H) CH,Or C,H, \CH----bH --- 9 C,H,<(TH --- CHnamely, [MI, 374*5”, found by Pickard and Neville.’R.H. Pickard and W. 0. LittleburyS have resolved ac-tetrahydro-Ann. Report, 1905, 174.3 Gazzetla, 1906, 36, ii, 392.Ibicl., 467.7 .7bid., 1905, 87, 1766.Annnlen, 1906, 349, 324.Tmns., 1906, 89, 935.Ibid., 1906, 89, 1252.lj &d., 1101STEREOCHEMISTRY 189by their method which involves con-CH,*F]H,CH,*CH*OH' 2-naphthol, C6H4<densation with I-menthylcarbamide and cry stallisation of the resultingmixture of the products ZBdA and ZRZA p in the present case the formercompound proves to be the less soluble and is readily hydrolysed,yielding the d-ac-tetrahydro-2-naphthol. This substance does notreadily undergo optical inversion, and therefore contrasts in behaviourwith the corresponding amine which Pope and Harvey1 found to bevery easily inverted.A' "-Dihydrophthalic acid was resolved into its active componentsby Proost by crystallisation with strychnine, and A.Neville has nowresolved the isomeric trans-A' : 5 - ~ ~ r n p ~ ~ n d ,CH/\HY YH*CO,G,HC CH*CO,H LI \/CHby crystallisation of its acid strychnine salt. The salt of the I-base withthe I-acid separates from the solution as the least soluble component.The cold aqueous solution of the Z-A-3:5-dihydrophthalic acid does notundergo optical inversion in the cold, b u t at 97" the inversion of thesodium salt proceeds as a unimolecular reaction ; the transformationoccurs, also as a unimolecular reaction, much more rapidly in presenceof excess of soda. From the solution remaining after the transformationthe optically inactive A2 ' 6-dihydrophthalic acid has been isolated,the change proceeding thus :CK C'H/\ /\\/ \/H$J $JH-CO,H NaHO H2V Y-CO,HHC CH*CO,H -+- H,C C*CO,HC H UHA.Neville has also resolved the 2 : 3-dibydro-3-methylindene-2-carb-oxyiic acid, C6~~,<~,HM"SCH*C0,H, into its optically active com-1ponents by crystallisation with I-menthylamine ; the salt ZBdA is themost sparingly soluble, and from this the pure d-acid is obtained.Although the acid contains two asymmetric carbon atoms only one d-and Z-acid were isolated.F. W. Kay and W. H. Perkin, j ~ n . , ~ have resolved syntheticdl- 1 -methyl-A3-cyclohexene-4-carboxylic acid,Trans., 1901, 79, 83. I! Ber., 1894, 27, 3185.Tm?ts., 1906, 89, 1744.4 lbid., 383. 6 B i d . , 839190 ANNUAT, REPORTS ON THE PROGRESS OF CHEMISTRY.by crystallisation with brucine and strychnine ; with the first basethe salt ZBZA is obtained as the less soluble, whilst with strychninethe salt ZBdA crystallises first. Prom these acids, by the aid of theGrignard reaction, the authors have succeeded in obtaining for thefirst time synthetic optically active terpenes and their derivatives.E. Erlenmeyer 5 has resolved dZ-a-brorno-p-phenyl-@-lactic acid,C6H5*CH(OH)*CHBr*C0,H, into its optically components by crystal-lisation with cinchonine and strychnine ; the corresponding chloro-derivative has been resolved by means of strychnine and the iodo-derivative with the aid of cinchonine. E. Erlenmeyer and C.Barkowhave prepared a dZ-P-amino-P-phenyl-a-lactic acid,C,H,*CH(NH,)*CH(OH)*CO,H,isomeric with that already known, by the action of ammonia on sodiumphenyl-lactate ; the lzvo-acid is prepared from sodium phenyl-lactate.CH,*CH,-CH,*CH,*CH(NH,) *CO,H,is excreted in the urine after administering externally Compensatedleucine to rabbits; leucine is in general not excreted in the urineof dogs, although in one case the administration of the inactiveamino-acid resulted in a small quantity of d-leucine being found inthe urine.On administering externally compensated alanine to dogs, A.Schittenhelm and A. Katzenstein findthe amino-acid is conveniently separated by aid of its a-naphthalene-sulphonic derivative.0. Warburg 4 shows that pancreatin hydrolyses leucine ethyl esterasymmetrically, Z-leucine, CH,*CH;CH2*CH,*CH(NH2)*C0,H, beingproduced.finds that by the action of yeast on a solution of sucroseand externally compensated alanine, leucine, or a-nminoisoraleric acid,both components of the amino-acid are attacked, but, in general, atvery different rates ; Z-alanine, d-leucine, or I-a-aminoisovaleric acidcan be readily separated from the product in a 65 to 75 per cent.yield,According to E. Reiss,o d-alanine is more readily utilised in theanimal organism than is its enantiomorphously related isomeride.P. Mayer7 finds that cl-lecithin is converted into dl-lecithin byheating to 100° with methyl alcohol, and that steapsin attacksE. Abderhalden and F. Samuely found that d-leucine,that only Z-alanine is excreted%. EhrlidhBcr., 1906, 39, 788.2 Zeit.physiol. Chenz., 1906, 47, 3-16. :? %&. mp. Pcd7i. 777iw.) 2, 5GO.Zeit. phylsiol. Chem., 1906, 48, 208.f, Biochem. Zeit., 1906,1, 8 ; Zeit. Yer. deut. Zuckwind., 1906, No. 608, 840.6 Beitr. chem. Physiol. Path., 1906, 8, 332. 7 Bioc7~.em. Zeit., 1906, 1, 39STEREOCITERSISl'RY 191dZ-lecithin, leaving Z-lecithin in the solution. 0. Riesser shows thatd-arginine is converted into a mixture of dl-arginine and dl-ornithineby heating with diluted sulphuric acid at 160-180°.A number of optsically active alkyl derivatives of benzene have beenprepared by A. Klages and R. Sautter.2 The fact that these hydro-carbons are formed without optical inversion from their sulphonicacids has led Klages 3 to attempt the resolution of sec.-butylbenzene,CHMeEtPh, by crystallising the sulphonic acid of the externallycompensated hydrocarbon with quinine, cinchonidine, and strychnine ;the attempts were not successful.Pschorr, Roth, and Tannhauser* show that the optically active a-and p-methylmorphimethines and a-etlhylthiocodide crystallise in thesphenoidally hemihedral subdivision of the orthorhombic system andafford examples of the recently discovered occurrence of opticalactivity 5 in the crystalline state of biaxial substances.I n view of the optical activity and other properties of tannin,J.Dekker 6 assigns to it the following constitution which indicatesthe presence of an asymmetric carbon atom in the molecule,?(OH): CH-E- GO*? gH*C(OH): ?*OHC(OH):C(OH)*C--C(OH)*C--CH==C*OH'Haller and March7 have prepared, and determined the specificrotatory powers of, hexahydrobenzyl-, hexahydrobenzylidene-, oen-anthyl-, and oenanthylidene-camphors ; the results confirm the pre-vious conclusion that the specific rotatory power of the unsaturatedderivative is higher than that of the corresponding saturated com-pound.The statement is made by E.Jungfleisch and M, GodchotS thatduring the preparation of d- or Z-lactide by heating the correspond-ing lactic acid, they observe that Z-lactic acid or Z-lactide is muchmore rapidly optically inverted by heat than the correspondingd-isomeride.I n continuation of previous work, J. B. Cohen and I. H. Zortmannhave prepared, and determined the rotation constants of, the 2-menthylesters of the isomeric dibromobenzoic acids,O and J.B. Cohen andH. P. Armes have prepared and examined the Z-menthyl esters of theisomeric chloronitrobenzoic lo and dinitrobenzoicR. H. Pickard and J. Yates12 have examined as a time reactionthe conversion of the sodium or methyl salts of cZ-Az-dihydro-l-acids.Zeit. pJn~s/sioZ. Chcm., 1906, 49, 210.Bey., 1906, 39, 1938 ; compare Ann. f i e p o d , 1905, 178.L'er., 1906, 39, 2497 and 3754.:! Ber., 1906, 39, 2131.8 Ibid., 637.16icl.) 19. Pocklington, Phil. Mag., 1900, 6, 2.T~cms., 1906, 89, 47.7 Compt. rei~cl., 1906,142, 316.lo Jhid.* 454. Ibid., 1479. 12 Ibid., 1484192 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.C(CO,€€):~H in naphthoic acid into the inactive Al-acid, C6HH,<CH2--CH,,presence of a number of basic hydroxides and bases ; the conversionproceeds as a unimolecular reaction and is easily followed polari-metrica1ly.l The hydroxides of the alkaline earths hasten the transfor-mation of the sodium salt more than the alkali hydroxides, and thelatter are rather more active than the tetra-alkylammonium hydroxides ;the relative strengths of the bases in this respect differ somewhatfrom the relative electric conductivities, and this is attributed to theeffect of the base on the electrolytic dissociation of the salt.R. H,Pickard, W. 0. Littlebury, and A. Neville have studied the reactionsbetween I-menthylcarbimide and a number of alcohols as time re-actions; the rotation constants of a number of esters of I-menthyl-carbamic acid have been determined.Further examples of asymmetric syntheses are given by A.M~Kenzie,~ who applies Grignard's reaction for this purpose.Theaction of magnesium propyl, isobutyl, tert.buty1, and a-naphthyliodides or bromides on I-menthyl benzoylformate and of magnesiummethyl, ethyl, iso-butyl, and a-nsphthyl iodides or bromides on I-bornylbenzoylformate leads in each case to an asymmetric synthesis of asubbtituted glycollic acid. I n each case a mixture of the d- and I-sub-stituted glycollic acids resulted on hydrolysis of the product, and inthis mixture one component predominated; the excess of onecomponent over the other was greater in the case of the rnenthyl thanof the bornyl esters.The asymmetric synthesis of phenymethyl-glycollic acid can be effected both by the action of magnesium methyliodide on I-menthyl benzoylformate and by that of magnesium phenylbromide on Lmenthyl pyruvate ; the former method leads to formationof excess of the Z-acid, whilst the latter gives the d-acid in largerquantity. A. McKenzie and H. Wren4 also effect an asymmetricsynthesis of I-lactic acid by the reduction of I-bornyl pyruvate andsubsequent hydrolysis of the p r ~ d u c t . ~have shown that on heating eitherdl- or I-mandelic acid, C,H,*CH( OH)*CO,H, with the equivalentquantity of brucine at 150-160' it becomes converted into d-man-delic acid, that is to say, the mandelic acid subsequently separatedshows a slight dextrorotation. Similarly, on heating dl-mandelicacid with strychnine or nicotine under the same conditions, therecovered acid is dextrorotatory.On heating dl-p-methoxymandelicacid with brucine or strychnine, it becomes dextrorotatory, andW. Marckwald and D. M. PaulAm. Beport, 1905, 174.]bid., 365. Jbitl., 688. Compare Ann. Zeport, 1905, 170.Ber., 1906, 39, 3654.Tyans., 1906, 89, 93STEREOCHEMISTRY. 193after heating P-phenyl-lactic acid with brucine the recovered acid isfound to be slightly I~vorotatory.Winther shows 1 that in the catalytic optical inversion of d-tartaricacid, i-tartaric acid is first produced, the reaction being one of the firstorder and reversible ; the generally accepted view that the dl-tartaricacid produced during the optical inversion of d-tartaric acid is a directproduct of the change is thus incorrect.The dFtzLrtaric acid obtainedis produced from d-tartaric acid, i-tartaric acid being formed as anintermediate product. The effect of alkalis in accelerating the opticalinversion of d-tartaric acid is connected with the presence of hydr-oxylic hydrogen, which becoines replaced by the alkali metal ; thusthe substance CO,Na*CH(ONa)*CH(OH)*CO,Na can be separated fromstrongly alkaline solutions of sodium tartrate and caustic soda. Nocorresponding compound containing potassium could be isolated and inaccordance with this it is observed that caustic potash exercises aslighter catalytic effect on the inversion than soda. He has also found athat the optical inversion of mandelic acid by caustic alkalis proceedsas a unimolecular reaction.finds that P-cholestene dibromitle gives [a], - 39.6'immediately after solution in chloroform but that the solution becomesoptically inactive in a day and after several days gives the specificrotatory power [a],, + 39.4" ; the change occurs more slowly in benzenesolution and the solution on evaporation yields the isomeric a-cholestenedi bromide,R.Torrese4 has shown that the hydrolysis of sucrose is notbrought about by glutaconimide derivatives of types (1) and (a), butthat those derivatives which contain the group (3)J. Mauthnerare alone capable of causing the hydrolysis. The presence of thesingle double linking in (3) is thus essential if the derivative is t obring about the hydrolysis of sucrose; further, if one of the carbonylgroups is replaced by the group CPlille,, the power to hydrolyse sucroseis lost.A convenient method for graphically representing the configurationsof sugar-like substances and their derivatives is given by Rosanoff ;he considers that the stereochemical classification of these and relatedsubstances would be rendered more consistent by regarding d-guloseZeit.phpsilial. Chenz., 1900, 56, 719.Monutsh., 1906, 27, 421.a ]bid., 465.Atti B. Accad. Xci. Torirzo, 1906, 41, 309.6 J. Amer. Chern. Soc., 1906, 28, 114.VOL. 111. 194 ANKUAL REPORTS ON THE PROGRESS OF CHEMISTRY.as belonging to the I-family and not to that of &glucose and by makingcorresponding changes in the nomenclature of other similarly relatedcompounds. He also discusses 1 the question of optical superpositionand states as a new principle that ‘ I the optical rotatory power of anasymmetric carbon atom depends upon the composition, constitution,and configuration of each of the four groups.”T.&I. Lowry 2 has applied his solubility method 3 for determiningthe proportions in which dynamic isomerides are in equilibrium i nsolution, t o the halogen derivatives of camphor, which Kipping hasshown to undergo reversible isomeric change in presenco of alkalis. Hefinds that the solubility of each of these substances which contains thegroup -CHBr*CO- or -CHCl*CO- is increased by approximately one-tenth by the addition of the alkali, but no such increased solubility isobserved with camphor derivatives containing the group -CH,*CO- or-CBr(NO,)*CO-.The extent to which the partial optical inversionoccurs is a result of the isodynamic reversal in sign of the asymmetriccarbon atom in the group -CHBr*CO- or -CHCl*CO-. T. M. Lowryand E. H. Magson4 have applied similar methods to the study of alarge number of sulphonic derivatives of camphor, and have obtainedevidence enabling the above conclusions t o be extended.T. Purdie and C. R. Young5 regard ordinary crystalline rhamnoseas the a-form and Fischer’s crystalline anhydrous rhamnose as the@-form of the sugar; they describe an improved method f o r thepreparation of the latter form, which involves assisting the changea -+ P t o occur.The P-rhamnose is stable a t high temperatures andthe a-€orm a t low temperatures; the former is I-rotatory and thelatter strongly d-rotatory in aqueous solution. A number of methyl-rhamnosides have been prepared and classified as of the a- and p-form.have isolated /3-methylarabinoside cor-responding to Fischer’s a-methylarabinoside from the mother liquorsobtained during the preparation of the latter ; both are unaffected byyeast enzymes or by emulsin. Trimetbyl-a-arabinoside is crystallineand was isolated ; the P-isomeride is apparently a liquid and has alower dextrorotation than the former.J. C. Irvine and A. Bl. Moodie7 have investigated the addition of alkyliodides to alkylated sugars and glucosides, and, from the behaviour oftetramethyl-a- and -P-glucosides and tetramethyl glucose towards suchsubstances, conclude that the observed mutarotation takes the followingcourse when the solutions are cooled and then reheated : (1) a decreasein rotatory power owing t o formation of an oxonium derivative ; (2) anincrease in rotatory power a t the lower temperature owing to theT.Purdie and 3%. E. RoseJ. Amer. Clzem. Xoc., 1906, 28, 524,Ibid., 1904, 85, 1541.Ibid., 1194. (i Ibid,, 1204, Did., 1578.Trans., 1906, 89, 1033.Ibid., 1906, 89, 1042STEREOCHE?UZISTKT. 195uncombined sugar changing in the direction p -+ a ; (3) a rapid risein rotatory power during reheating owing to the dissociation of theoxonium derivative; and (4) a fall in rotatory power a t the highertemperature due to the change a -+ p in the sugar,P.Waldenl has determined the rotation constants of a largenumber of optically active esters and other substances for light ofdifferent wave-lengths under a variety of different conditions ofsolvent, concentration, and temperature. H e concludes that therotatory dispersion is a highly constitutive property, and is in the mainindependent of the temperature and solvent ; homologous substanceshave practically the same rotatory dispersions, but deviations fromthis rule are found in the lower members of a homologous series. Ahigh rotatory power usually accompanies a high rotatory disper-sion, although this is not always true, the two constants being notgenerically related. Most solvents have li?hle influence on therotatory dispersion of a dissolved substance, but some, which differwidely in constitution and optical properties, exert a distinct in-fluence on the rotatory dispersion of the solute.A few solvents,such as chloroform, quinoline, and cinnamaldehyde, sometimes effecta complete change in the rotatory dispersion of the solute; thisalteration is to be traced to chemical change leading to the forma-tion of new optically active complexes. Walden replies to Patterson'scriticism of his previous conclusion^,^ quoting a large amount of freshexperimental data, and adhering to his former statement that adirect relation is observable between the molecular weight and therotatory power of an optically active substance in both concentratedand dilute solutions.C. Winther contributes a quantity of experimental data fromwhich he concludes that a simple relation exists between changes ofrotatorypower on the one hand and the specific volume and molecularweiiht on the other.I n the case of certain substances, such asnicotine and amyl itaconate, the results obtained a t differenttemperatures indicate that the changes in rotatory power are duesolely to changes in the molecular volume or molecular solutionvolume ; the same holds in numerous cases investigated by Franklandand Patterson, in which the rotatory power and molecular volumechange proportionally when the temperature is altered. I n other cases,such as those of menthol, ethyl and propyl tartrates, and diethyldibenzoyltartrate, the changes of rotatory power are functions of thechanges in molecular volume and also in molecular weight.If acertain change in rotatory power, A[a], occurs as the result ofthe quantity, Am,, of single molecules being produced from doubleZeit. pkysiknl. G ' l z m . , 1906, 55, 1. BcT., 1906, 39, 6%.Zeit. physiknl. Chcm., 1906, 55, 257 ; 56, TO,?. 3 Ann. Eepoyt, 1905, 176.0 196 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.molecules in the liquid by a rise of temperature, T, the change inrotatory power should be represented byA[a] = K-Am, + K',*Av = 1ClaAT/T17, + IC2*Av.This expression applies satisfactorily to the substances last mentionedboth in the undissolvecl and dissolved state. The amount of associationoccurring in the solutions may be determined from a knowledge ofthe changes in rotatory power ancl in molecular volume, becauseK* An?, = A[a] - hr2*4v.Cases like those of nicotine and ethyl tartrate, in which A[.]=E A v , are found in camphor and turpentine in the dissolved state.Grossmann and Wieneke from an extensive series of rotatorypower determinations a t different temperatures and concentrationsconclucle that in aqueous solution boric acid and tartaric acid form Rmonoboryl tartaric acid,CO,H* CR(0H) 'CH(0H) CO; BO, the hydrolyticdissociation of which increases with rise of temperature and decreaseof concentration.The sodinm salt of this acid appears to exist insolution arid evidence of the forlaation of a sodium boryl bitartrateis also adduced. Both normal and acid tartrates and malates of pyrirlineexist in aqueous solution.With the aid of the approximately monochromatic light of mave-length4SS.5pp which passes throngh R pale-blue light filter, H.Grossniannhas investigated the optical effect of adding alkaline copper solutionsto solutions of c2-glucose, d-fructose, d-mannitol, rl-rhamnose, sucrose,isosaccharin, asparagine, and tartaric and quinic acids. The effect ofthe alkaline copper solution is in all cases greatly to increase therotatory power, and in the cases of glucose, fructose, sucrose, ancl1-hamnose, the sign of the rotation is reversed. The maximum changesin specific rotatory power due to the addition of copper solution arefrom + 78.0" to - 375" with glucose, - 134.5Oto + 1423' with fructose,+1012" to - 111.3' with sucrose, and +72*Oo t o +1327" withtartaric acid.T.S. Patterson and J. Ksye3 have examined Z-menthyl 2-tartratefor purposes of comparison with Z-menthyl d-tartmte.4 Z-Mentbyl&tartrate gives [MI, - 35S.1" a t 15' and - 382.5" a t 103" in the purestate and, together with its diacetyl derivative, has been examined in anumber of solvents. It is shown that the optical effect of each com-ponent optically active group in the two diacetyl derivatives is roughlytraceable in the changes of molecular rotatory power which occur onheating from 0' t o 100' and the results are ciiscussed in connexionwith the question of optical superposition,T. S. Patterson and J. Frew5 have determined the rotatory powersTmns., 1906, 89, 1884.Zrit.pJbpiku2. Chcna., 1906, 54, 385.Zeit. Ycr. dczit. Zz~ckeerincl., 1906, No. 610, 1024.Awl. B~porf, 1905, 176. Ti T m w , 1906, 89, 332STE RE0 CH El1 I STR Y. 197of I-menthyl benzenesulphonate and P-naphthalenesulphonate in alcohol,benzene, and nitrobenzene solutions at different temperatures and con-centrations ; the values for the benzenesulphonate are larger than thosefor the other ester, and in each case the highest values are obtained inalcohol solutions, the lowest in nitrobenzene, and intermediate valuesin benzene solutions.I n addition to those previously described,l P. F. Frankland andD. F. Twiss2 have determined the rotatory powers of a numberof other derivatives of tartramide; i t is notable t h a t the specificrotatory power of d-tartaric diallylamide is less than that of thedipropylamide, as this forms an exception t o the general rule that theintroduction of a double bond increases the specific rotatory power. Asimilar observation is made by P.E. Frankland and E. Done 3 in a ninvestigation on the influence of substituents on the optical activity ofnialamide; it is there shown t h a t maldi-n-propylamide has a higherspecific rotatory power than maldiallglamide.The autorscemieation of iodides and bromides of optically activequarternary ammonium bases in chloroform solution f i t st observed inthe case of phenyl benzylmethylallylammonium compounds and tlleoptical stability in aqueous solution of the corresponding salts ofthe same base in aqueous solution4 have been reinvestigated byWedekind in connexion with the iodide, bromide, chloride, andfluoride of d-phenylbenzylmethylpropylammonium. As in the firs t-mentioned case, the iodide undergoes autoracemisation in chloro-form solution more rapidly than the bromide; with the fluoride nodefinite indication of autoracemisation was obtained and the hycir-oxide in chloroform solution becomes slowly optically inverted, althoughWedekind hes previously noted that another optically active substitutetlammonium hydroxide is optically stable in aqueous solution.E.WedekindG finds t h a t the optical inversion of phenylbenzyl-methyl-, allyl-, -propyl- and -isobutyl-ammonium iodides proceeds as :tuoimolecular reaction. The molecular weight of the first compound isnormal, so that but very slight dissociation can exist in the chloroformsolution.H. Goldschmidt tloes not consider it certain that Wedekind’smeasurements completely establish that the optical inversion is due todissociation into tertiary amine and alkyl iodide ; he contributes Rthermodynamical discussion of the process of optical inversion.sE. Wedekind and E. Friihlich !’ remark that the molecular rotatorypowers previously given by Wedekintl and Jones for the opticallyTrans., 1903, 83, 1349. IDicl., 1906, 89, 1855. Ibid., 1859.Zcit. Elelctrochesn., 1906, 12, 330.Ibid., 416 and 516..i Trans., 1901, 79, 838. Bcr., 1906, 39, 474.3 Compare Weclekind, ibicl., 1906, 12, 515. EcT., 1906, 39, 4437198 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.active ion *NMeEtPh*C,H7 are not such as would be expected fromthe values obtained for the ions*NMePrPh*C7H7 and *NMe(isoC,H,)Ph.C~Hp.I n accordance with this it was found that prolonged fractional crystal-lisation of the mixed d- and Z-phenylbenzylmethylethylammoniumd-camphorsulphonates led t o the separation of a fraction, dEdA, havinga much higher rotatory power than in the previous work and fromwhich the value [MI, + 64.4' was obtained for the basic ion.The iodideof the active base undergoes optical inversion rapidly in chloroform butnot in alcohol solution.Wedekind agrees with Jones's view 1 that the so-called P-phenyl-benzylmethylallylammonium iodide is really phenylbenzyldimethyl-ammonium iodide, which is formed in the reaction between phenyl-benzylallylamine and methyl iodide by a replacement of the allyl groupby methyl ; he describes several cases of a similar kind in which an allylor benzyl group is thus displaced by methyl during the formation of aquarternary ammonium iodide. There is therefore at present noknown case of stereoisomerism amongst optically inactive asymmetricnitrogen derivatives.2have determined for purposesof comparison the rotation constants a t cliff erent temperatures and con-centrations of a large number of compounds owing their activity t othe presence of a asymmetric nitrogen atom ; the interpretation in thelight of Guye's formula of the large quantity of valuable data quotedled to no satisfactory agreement being established between theobserved and the calculated values.A. Ladenburg4 has continued work on the peculiar kind of stereo-chemical isomerism which he believes to occur amongst secondarybases like stilbazoline and coniinem5 Whilst the naturally occurringd-coniine has [u], +15*6", the base obtained by resolving syntheticconiine with a?-tartaric acid gives [aID + 19.2'; the latter Ladenburgregards as d-isoconiine. The only difference observable between t h eproperties of the t w o :bases and their derivatives is in the specificrotatory power. d-isoconiine undergoes practically complete conversioninto d-coniine OF [.ID + 15.7' on heating at 290-300".Miss 31. B. Thomas and H. 0. Jonesw. J. POPE.Awn. Report, 1905, 182.Ber., 1906, 39, 2486.Ber., 1906, 39, 481. Trans., 1906, 89, 280.Am. Report, 1904, 144