Commercial notes and scientific information. 23 



material, or fruit and seeds with alcohol of about 80 p. c. In this treatment the water 

 which is present in the cells dilutes the spirit to the desired strength. 



Rosenthaler 1 ) has made experiments in decomposition with several of these emulsin- 

 preparations, but it would lead us too far describe them in detail. 



In conclusion, Rosenthaler gives an arrangement to indicate the processes which 

 take place in the amygdalin-emulsin system. This arrangement we reproduce textually 

 below: — 



I. Amygdalin, by the action of amygdalase, affords mandelonitrile glucoside and 



glucose. 

 II. Mandelonitrile glucoside is resolved by the action of prunase into cZ-benzalde- 

 hyde cyanohydrin and glucose. 



III. d-benzaldehyde cyanohydrin is resolved by d-oxynitrilase into benzaldehyde 

 and hydrocyanic acid. 



IV. Benzaldehyde and hydrocyanic acid unite under the influence of a d-oxynitrilese 

 to form d-benzaldehydecyanohydrin. 



V. In addition, benzaldehyde and hydrocyanic acid afford inactive benzaldehyde 



cyanohydrin. 

 VI. Inactive benzaldehyde cyanohydrin is capable of being split up asymmetrically 

 by d-oxynitrilase, giving rise to Z-benzaldehyde cyanohydrin. But in emulsin- 

 preparations which are rich in this enzyme it is possible that, as a result, the 

 benzaldehyde cyanohydrin which is formed in the process of the decomposition 

 of amygdalin may be laevorotatory. 



It will remembered that at the time we referred to an interesting asymmetric 

 synthesis of ^-benzaldehyde cyanohydrin which had been carried out by L. Rosenthaler 2 ) 

 from benzaldehyde and hydrocyanic acid by the action of emulsin. G. Bredig and 

 P. S. Fiske 3 ) have now discovered that when an optically active alkaloid is used as a 

 catalyser the generation of benzaldehyde cyanohydrin from its components, hydrocyanic 

 acid and benzaldehyde, takes an optical-asymmetric course, that is to say, that asym- 

 metric synthesis can be achieved by a catalyser of known constitution exactly in the 

 same manner as by an enzyme. Bredig and Fiske employed quinine and quinidine as 

 catalysers. With quinine, a dextrorotatory cyanohydrin was obtained, which undei 

 saponification gave rise to Z-mandelic acid, while with quinidine, an isomeride of 

 quinine, laevorotatory cyanohydrin and dextrorotatory acid were obtained. In equivalents 

 (molecules) the quantity of the optically active mandelic acid which is obtained is 

 greater than that of the alkaloid which has been used as a catalyser, hence the 

 character of the reaction as a catalysis is assured. The authors mention the curious 

 fact that the cyanohydrins possess a remarkably strong affinity with alkaloids such 

 as quinine, quinidine, 8jc. This is the reason why, in certain circumstances, it is ex- 

 ceedingly difficult to remove the latter from anhydrous cyanohydrin solutions by 

 shaking out with aqueous hydrochloric acid and why, on the other hand, a non aqueous 

 benzaldehyde cyanohydrin solution is capable of completety abstracting the alkaloid 

 from an aqueous hydrochloric acid solution by shaking-out. 



F. D. Dodge 4 ), who has taken up the estimation by titration of benzaldehyde (also 

 see p. 124), has given some particulars of his investigations at the Eighth International 



*) Arch, der Pharm. 251 (1913), 85. — 2 ) Biochem. Zeitschr. 14 (190S), 23S; Report April 1909, 17. — 

 3 ) Biochem. Zeitschr. 46 (1912), 7. From a reprint kindly sent to us. — 4 ) 8th International Congress of Applied 

 Chemistry, Washington and New York, 1912. Vol. XVII, p. 15. 



