Studies with polyfunctionally substituted heterocycles: New synthesis of pyrido[5 ',4 ': 2,3][1,3,4]oxadiazolo[3,2-a]pyridine; pyridazine; 1,3,4-oxadiazole; and Pyrazolo[1,5-a]pyrimidine derivatives

摘要

Cyanoacetohydrazide 1a reacts with 2-arylhydrazoketons 2a,b and 3a,b in refluxing ethanol to yield pyrido[5',4':2,3][1,3,4]oxadiazolo[3,2-a]pyridine and pyridazine derivatives; in the absence of solvent pyrazolo[ 1,5-a]pyrimidine derivatives were obtained. The reaction of 2a,b and 3a,b with benzoylhydrazine afforded 1,3,4-oxadiazole and pyrazole derivatives. [References: 6]