Formation of Organic Compounds 91 



It can be shown [6] that if the reaction of the aldehyde, hydrogen cyanide, 

 and ammonia to form the amino- and hydroxy-nitriles is a rapid and reversible 

 equilibrium and that the hydrolysis is a first-order irreversible reaction, then 

 the ratio of hydroxy acid to amino acid at the end of the nm will be 



Ri= hiHilhKi^^^), (i) 



where Hi and Ki are the equilibrium constants for the formation of the hydroxy 

 and aminonitrile from aldehydes, and hi and ki are the respective rates of hydro- 

 lysis. Similarly we have 



R2 = A/^-methylamino acid/amino acid 

 = -miMi (CH3NH2)/AiiCi (NH3), 



where Mi and mi are the equilibrium constant and rate constant of hydrolysis 

 of the methylaminonitrile. 



^-Alanine cannot arise from a Strecker synthesis as with the a-amino acids, 

 A reasonable mechanism would be from a Michael addition of ammonia to 

 acrylonitrile, acrylamide or acrylic acid. One would expect that hydrogen cyanide 

 and methylamine would also add to give, after hydrolysis, succinic acid and 

 iV-methyl-i8-alanine, iV-Methyl-^-alanine was not detected during the analysis 

 since it does not react with ninhydrin. The rate of formation of the nitrile of 

 )8-alanine and succinonitrile would be 



Knh^ (NH3) (CH2 = CHCN) and Khcn (CN-) (CH2 = CHCN), 



respectively, where the i^'s are the rate constants for addition. Assuming that 

 the addition is irreversible and that the nitriles are hydrolysed by the end of the 

 rtm, then 



(Succinic acid)/(/S- Alanine) = Khcn{CH-)IKnh^{^^z). 



This treatment is easily generalized to include additions to acrylonitrile and 

 acrylic acid. The ratios of products are given in Table 3, 



If the ratio hHjkK does not depend on the aldehyde, then equation i pre- 

 dicts that the ratio of the hydroxy acid to the amino acid should be the same for 

 the different aldehydes in a given rtm. The agreement is good for the spark dis- 

 charge and silent discharge except for hydroxybutyric/aminobutyric in the 

 silent discharge. In Run 4 the hydrolysis of the amino- and hydroxy-nitriles was 

 necessarily the mechanism for synthesis of the respective acids. There is less 

 agreement of the ratios than with the electric discharges, but the agreement is 

 within the errors of the experiment. 



Similarly the ratios of metliylamino acid/amino acid are nearly the same for 

 Run I and 3. The succinic acid/j8-alanine ratio is the same in Runs i and 6, 



The ratios of various products are in qualitative agreement in all cases and in 

 quantitative agreement (within the experimental error) in most of the cases. 

 The similarity of products in Runs i and 4 is striking (except for the expected 

 absence of ^-alanine and succinic acid since no acrylonitrile was added), suggest- 

 ing that the products were formed by the same mechanism. 



