Chemistry of Some Heterocyclic Compounds

Abstract

The study comprises the reactions of 2-amino-3- cyano-4,5,6,7-tetrahydrobenzo[b]thiophene (3c) and 2-amino-3-cyano-4,7-diphenyl-5-methyl-4H-pyrano[2,3-c] • pyrazole (14) with variety of reagents including electro­ philes and nucleophiles. Thus treatment of compound 3c with propanedinitrile derivatives (17a&b) in refluxing n-butanol affords E,Z-mixtures of 3-phenyl-2-[2-(4-amino-5,6,7,8-tetrahydro benzothieno[2,3-d]) pyrimidinyl]propenonitrile (184a) and 3-phenyl-2-[2-(4-amino-5,6,7,8-tetrahydrobenzothieno[2,3-

d])pyrimidinyl]but-2-enonitrile (184b), respectively. On the other hand, similar treatment of compound 14 with propanedinitrile derivative (17b) produces 3-carboxy-2- substituted aminopyrano-pyrazole derivative (185). Compound 3c reacts with phenylisocyanate (42b) in refluxing pyridine to give 2-(N3-phenyl-N1-ureido)-3- cyanothiophene derivative (188) together with 1,3- diphenylurea (189) and 1,3,5-triphenylbiuret (190).