306. 



Marckwald and MacKenzie l ) determined the ratio of 

 etherification- and saponification- velocities of the laevo-, and dextro- 

 gyratory mandelic acids with respect to l-menthol, at a value of 0,90. 

 If the saponification be completed, the free acid obtained is inactive, 

 which is a fresh proof, that both antipodes have the same affinity 

 for the optically active menthol. Laevogyratory octyl-alcohol was 

 etherified somewhat more rapidly by dextrogyratory tartaric acid 

 than the corresponding dextrogyratory octyl-alcohol', however, the 

 last is etherified more rapidly by laevogyratory tartaric acid, -as would 

 be expected. The velocities of the saponification differ in this 

 case appreciably more than the velocities of the etherification, a 

 difference much more pronounced here than in the case of the 

 merithol-mandelates mentioned above. 



In the year 1900 Cohen and Whiteley 2 ) and later Kip- 

 ping 3 ) made some unsuccessful experiments of the same kind, 

 and equally unfortunate were the attempts of Fischer and his 

 collaborators 4 ) in 1910, as well as those of Scholtz. 5 ) 



Cohen and Whiteley 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 : 



CH 3 .C(COOC 10 H 19 ) : CH.COOC 10 H 19 -> CH 3 .CH(COOC 1 oH 1 9).CH 2 .COOC 1 oH 1 9 



->CH 3 .CH (COOH) .CH 2 -COOH . 

 C 6 H 5 .CH: C(CH 3 ).COOC 10 H 19 -> CQH 5 .CH 2 .CH(CH 3 ).COOC W H 19 



->C 6 H 5 .CH 2 .CH (CH 3 )COOH. 



Analogous reactions take place if bromine be added to the double 

 bond of the l-menthyl-, or l-ainyl-eiher of cinnamic acid: 



C 6 H 5 .CH: CH.COOC 10 H 19 -> CeHg.CHBr.CHBr.COOCjoHjg 



> C 6 H 5 .CHBr.CHBr.COOH 



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



CH 3 .CO.COOC 10 H 19 -> CH 3 .CHOH.COOC 10 Hi 9 > CH 3 .CHOH.COOH. 



!) W. Marckwald and A. MacKenzie, Ber. d. d. Chem. Ges., 34, 469, (1901). 

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

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



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



4 ) E. Fischer, Ber. d. d. Chem. Ges., 34, 629, (1901); E. Fischer and M. 

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

 (1902), p. 597. 



5) M. Scholtz, Ber. d. d. Chem. Ges., 34, 3015, (1901). 



