Synthesis and potential biological activity of some novel 3-[(N-substituted indol-3-yl)methyleneamino]-6-amino-4-aryl-pyrano(2,3-c)pyrazole-5-carbonitriles and 3,6-diamino-4-(N-substituted indol-3-yl)pyrano(2,3-c)pyrazole-5- carbonitriles

Abstract

Starting from N-substituted indole-3-carboxaldehydes (1a-g) a series of new 3-[(N-substituted indol-3-yl)methyleneamino]-6-amino-4-aryl-pyrano(2,3-c) pyrazole-5-carbonitriles (3a-g and 4a-g) have been synthesized via the acid catalyzed condensation reaction of 1a-g with 3-amino-5-pyrazolone, followed by the reaction with arylidene malononitriles. A series of new 3,6-diamino-4-(N- substituted indol-3-yl)pyrano(2,3-c)pyrazole-5-carbonitriles (7a-g) have been prepared either via the base catalyzed condensation reaction of 1a-g with 3-amino-5-pyrazolone to give 6a-g, followed by the reaction with malononitrile or by the reaction of N-substituted-3-indolylidene malononitriles (5a-g) with 3-amino-5-pyrazolone. According to the obtained results, the newly synthesized compounds possess significant anti-inflammatory, analgesic and anticonvulsant activities. The anticonvulsant potency of certain tested compounds was more pronounced than both anti-inflammatory and analgesic activities. Moreover, most of the newly synthesized compounds possess potential antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa.