Convenient synthesis of azolopyrimidine, azolotriazine, azinobenzimidazole and 1,3,4-thiadiazole derivatives
Several pyrazolo[1,5-a]pyrimidine, triazolo[1,5-a]pyrimidine, pyrido[1,2-a]-benzimidazole, pyrimido[1,2-a]benzimidazole, pyrazolo[5,1-c]triazine, triazolo[5,1-c]-triazine, triazino[4,3-a]benzimidazole and 1,3,4-thiadiazole derivatives were synthesized via the Ladders reactions of (E)-3-oxo-5-phenylpent-4-enenitrile and the versatile, hitherto unrep