Syntheses of Oxazolecarboxylic Acid Derivatives. XII. Hydrogenolysis of Aminoxazoles. (5). Syntheses of Alkenylureas

Acid azides (IV) have been prepared by the reaction of (E)- and (Z)-alkenoic acids (IIa-d) with diphenyl phosphorazidate. The isocyanates (V) formed by the rearrangement of IV were converted to (E)- and (Z)-alkenylureas (Ia-b) by the addition of ammonia. It was found that (Z)-acid chloride ((Z)-III) isomerized to (E)-III by heat, (Z)-IVa, c, d isomerized to (E)-IVa, c, d in the presence of triethylamine, and (E)-Va was polymerized to a trimer (VI) by the catalysis of triethylamine, triethylphosphine, and pyridine.