SYNTHESIS OF FUSED AND SPIRO HETEROCYCLIC COMPOUNDS DERIVED FROM 3,5-PYRAZOLIDINEDIONE DERIVATIVES

Abstract

The reaction of compound 1 with triethyl orthoformate afforded 2, which in turn reacted with CS2 and active methlyene compounds or malononitrile to give dithiolane and 4-malononitrile methylene derivatives 3,4, respectively. Treatment of compound 4 with active methylene compounds afforded spiro cyclopentene derivatives 5a-c. Compound 1 was reacted with bromomalononitrile or CS2 and halocompounds to afford furo-. thieno- and dithiolano-pyrazole derivatives 6–11, respectively. The reaction of compound 12 with phenacyl bromide or benzylidenemalononitrile furnished oxathiol-2-ylidene and pyridinethione derivatives 13,14, respectively. The dibromo derivative 16 was reacted with CS2 and active methylenes or malononitrile to obtain spiro dithietanes 17a-e and 4-dicyano-methlyene derivative 22, respectively. Compounds 17 underwent a cycloaddition reaction with thioglycolic acid, N-phenylbenzohydrazindoyl bromide, 2,5-dimethylfuran and 1-phenyl-3,5-pyrazolidinedi one to give cycloadducts 18–21, respectively. Treatment of > o-aminothiophenol or o-phenylenediamine with the dicyano compound 22 leads to the formation of spiro thiazepine or spiro diazine derivatives 23a,b . The arylidene derivatives 24 was reacted with S,S-acetals, N,S-acetals or ammonium dithiocarbamate to afford dithiane, oxazine or pyrazolodithiocarbamate derivatives 25–29, respectively. Chemoselective cyclization of compound 29 with H2SO4, NaOH or MeI gave compounds 30–32, respectively. Benzopyrano derivatives 34,36 were obtained through the reaction of compound 1 with a mixture of thiourea, triethyl orthoformate and ethyl cyanoacetate or with cyanoketene S,S diacetals, respectively.