Transformations of Acylation Products of Functionally -Substituted -Alkyl(aryl)-5-hydrazino-l,3-oxazoles into 1,3,4-Oxadiazole Derivatives

摘要

Acylation products of 2-aryl-5-hydrazino-4-X-l,3-oxazoles [X = C(O)OAlk,P(O)(OAlk)_2],when heated in acetic acid or ethanol,undergo recyclization and transform into the derivatives of l,3,4-oxadiazol-2-ylglycine or its phosphonyl analog.A similar rearrangement also occurs in the reactions of 2-alkyl(aryl)-5-hydrazino-l,3-oxazole-4-carbonitriles with carboxylic acid chlorides in pyridine,but it is accompanied by additional cyclization involving the amide residue and nitrile group,yielding 2-(5-amino-l,3-oxazol-4-yl)-1,3,4-oxadiazole derivatives.