Synthesis and Biological Activities of 6-Aryl-1,2,4 Triazolo (3,4-a) Phthalazines and 6-Aryl-Tetrazolo (5,1,-a) Phthalazines

Reaction of 1-hydrazino-4-phenylphthalazine and 4-benzyl-1-hydrazinophthalazine with aromatic aldehydes gave the corresponding colored hydrazones. Catalytic dehydrogenative cyclization of these hydrazones afforded the 3,6-diaryl-1,2,4-triazolo (3,4-a) phthalazines. The latter compounds were also obtained from the reaction of 1-chloro-4-phenylphthalazine and 4-benzyl-1-chlorophthalazine with aromatic acid hydrazides. Oxalic and malonic acid dihydrazides reacted with two equivalents of the former imidoyl chloride to give bis-triazolophthalazine derivatives. Reaction of the two imidoyl chlorides with sodium azide gave the corresponding 6-aryl-tetrazolo (5, 1-a) phthalazines. Some of the prepared compounds were tested for their insecticidal and nematicidal activities and found to be inactive.