291 



i "i- the optically active menthol Laevogyrntc octyl-akohol was 

 . th.riticd somewhat more rapidly by dextrogyra.ii tttrtiirif a 

 than tin- -nt -spending df&rtrogyratory odyl-alcohol ; h. . the 



la-t is rthiTified more rapidly by /a^ogyrate tartaric acid, as would 

 b<- expected. The velocities of the saponifiration differ in this 

 case appreciably more than the velocities of the etherification, a 

 difference much more pronounced here than in the case of th< 

 nioilhol-mandelates mentioned above. 



In the year 1900 Cohen and White ley 1 ) and later Kip- 

 ping 2 ) made some unsuccessful experiments of the same kind, 

 and equally unfortunate were the attempts of Fischer and hi- 

 collaborators 3 ) in 1910, as well as those of Scholtz. 4 ) 



Cohen and White ley started with the l-menthyl-eihers of 

 mesaconic acid and of phenyl-crotonic acid, and reduced them by 

 addition of hydrogen-atoms at the double bond, thus producing a 

 new asymmetric carbon atom (denoted by *) in the molecule : 



,J I... : ( I I.COOC, Hi 9 -> CH 3 .CH(COOC,oH 19 ).CHj.COOC 10 H 19 ->- CH S .CH(COOH).CH S .CC 

 : C(CH,).COOC 10 H 19 > C 6 H 5 .CH 2 .CH(CH S ).COOC 10 H 19 -> C 8 H 5 .CH,.CH(CH,).COOH. 



Analogous reactions take place if bromine be added to the double 

 bond of the l-menthyl-, or /-my/-ether of cinnamic acid: 



I S .CH : CH.COOC 10 H 19 > CH 5 .CHBr.CHBr.COOC 10 H, 9 -> C 6 H s .CHBr.CHBr.COOH 



or if l-menthyl-rac.pyruvate be reduced by hydrogen: 



CHj.CO.COOC 10 H 19 -> CH3.CHOH.COOC 10 H 19 -> CH S .CHOH.COOH. 



Something analogous was formerly proposed by Hart wall, 6 ) 

 who expected a one-sided synthesis by the reduction of tin 

 citraconates and mesaconates of optically active alcohols such as 

 menthol or borneol; but he did not make experiments in thi- 

 direction. 



Kipping studied the addition of hydrogen to quinine-pyrm <//(-. 

 quinine- levulinale, bornyl-pyruvate , or to its oxime, and to bornyl- 



1) J. B. Cohen and C. E. Whiteley, Proceed. Chem. Soc. 16. 212. (1900); 

 Journ. Chem. Soc. 79. 1305. (1901). 



2) F. S. Kipping, Proceed. Chem. Soc. 16. 226. (1900). 



8) E. Fischer, Ber. d. d. Chem. Ges. 84. 629. (1901); K. Fischer and M. 

 Slimmer, Ber. d. d. Chem. Ges. 36. 2575. (1903); Sitzb. Ak. der Wiss. Berlin, 

 (1902), p. 597. 



4) M. Scholtz, Ber. d. d. Chem. Ges. 84. 3015. (1901). 



B) G. Hartwall, Inaug. Dissert., Helsingfors, (1904). 





