ASYMMETRIC SYNTHESIS OF AMINO-ACIDS BY CATALYTIC REDUCTION OF AZLACTONES OF SUBSTITUTED ACYLAMINOACRYLIC ACIDS .5. HYDROGENATION OF AZLACTONES IN ALCOHOLS

1. The composition and ratio of the products obtained by the hydrogenation of 2-methyl-4-arylidene-5-oxazolones in alcohols are determined by the acidity of the solvent. 2. Hydrogenation of the azlactones in alcohols in the presence of triethylamine leads to the corresponding acylamino esters. In the presence of a primary amine the amides and esters of the acylamino acids are formed. 3. The mechanism of the reductive alcoholysis of the azlactones is discussed. It takes place through the formation of saturated azlactones with subsequent opening of the azlactone ring at the surface of the unsymmetrical Pd catalyst. © 1979 Plenum Publishing Corporation.