Synthesis and Molluscicidal Activity of Some 1,3,4‐Triaryl‐5‐chloropyrazole, Pyrano[2,3‐c]pyrazole, Pyrazolylphthalazine and Pyrano[2,3‐d]thiazole Derivatives

Abstract

2‐(5‐Chloro‐1,3‐diphenyl‐1H‐pyrazol‐4‐ylmethylene)‐malononitrile 1a reacts with the arylidenes of malononitrile 2a–d to afford the triaryl‐5‐chloropyrazoles 3a–d, respectively. 1a reacts with the active methylene pyrazolinones 5a, b and 12a, b to afford different products 8, 9, 10, 11, and 14a, b – depending on the substitution in the pyrazole ring. Compound 1a reacts also with the pyridazinone derivative 15 to afford the phthalazinone 16, and with the thiazolinones 17a–c to afford the pyrano[2,3‐d]thiazoles 20a–c, respectively. It reacts also with the malononitrile dimer 21a and with ethyl cyanoacetate dimer 21b to yield the pyrazolyl pyridines 22a, b, respectively. The synthesized compounds showed a moderate molluscicidal activity towards Biomphalaria alexandrina snails.