Orthoamide und Iminiumsalze, CV. Umsetzungen von Orthoamiden der Alkincarbonsäuren mit Carbonsäureamiden

Abstract

The reaction of an orthoamide derivative of phenylpropiolic acid (22a) with primary and secondary amides gives rise to the formation of a wide spectrum of reaction products. The reaction of 22a with formamide delivers a N-carbamoyl-cinnamic acid amidine, wheras the analogous reaction with methylene-diformamide leads to a ketenaminal, which is substituted in β-position by a N-formylimino group. From the orthoamide 22a and phthalimide a phthalic acid amide amidine is obtained. In contrast the reaction of diformamide with 22a affords a β-imino enamine. 2,6-Diaminopyridines can be obtained from 22a with acetamide, propionamide and butyramide in low yields. The pyridines are characterized as perchlorates. From 22a and benzamide a 4-amino-2,6-diphenylpyrimidine is obtained in low yield. In the reaction of the closely related orthoamide derivative of 4-Cl-phenylpropiolic acid 22b with benzamide are isolated as a further products two pyrimidine derivatives. A pyrimidinone and a vinylogous thiourea can be obtained from 22a and urea and thiourea, respectively.