R. Bakthavatchalam et al., 2,6-DIARYLHEXAHYDRO-4-PYRIDAZINOLS BY ACID-CATALYZED CYCLIZATION OF BENZALDEHYDE ARYL-2-(2-PROPENYL)HYDRAZONES, Journal of heterocyclic chemistry, 33(1), 1996, pp. 213-216
Treatment of benzaldehyde 1-(2-propenyl)-4-methylsulfonylphenylhydrazo
ne (1f) with 45% sulfuric acid gave hylsulfonylphenyl)-6-phenylhexahyd
ro-4-pyridazinol (2f) in 35% yield rather than the expected -(4-methyl
sulfonylphenyl)-1-(2-propenyl)hydrazine. The halogen-substituted hydra
zones 1c-1e and benzaldehyde 1-(2-methyl-2-propenyl)phenylhydrazone (1
b) gave similar results.