THE MECHANISM OF ORGANIC SYNTHESIS 133 



time. It has been suggested by Magnus Levy and by Leathes that 

 the transformation may occur by way of lactic acid. We have seen 

 already that glucose and the sugars of analogous composition may 

 be converted under the influence either of sunlight or of micro- 

 organisms into lactic acid. Lactic acid breaks down with readiness 

 into aldehyde and formic acid. 



CH. 



CH. 



CHOH = 



COOH 



Aldehyde undergoes condensation to form aldol. 



CHO-f H 



COOH 



CHO 



aldehyde 



CHOH 

 CH 2 



CHO 



aldol 



Aldol reacts with water and undergoes a shifting of its OH and H 

 groups, in a manner with which we are already familiar as occurring 

 in the conversion of glucose into lactic acid, forming butyric; acid. 

 We may represent the reaction in the following way, placing the^water 

 molecules opposite those groups of the aldol molecule with which they 

 react : 



CH, 



HO 



H 







gives 



CH 2 

 C;H OH 



CH 3 

 CH 2 



CH 2 



I 

 COOH 



