Synthesis of fused and spiro heterocyclic compounds derived from 3,5-pyrazolidinedione derivatives

The reaction of compound 1 with triethyl orthoformate afforded 2, which in turn reacted with CS2 and active methlyene compounds or malononitrile to gi ve dithiolane and 4-malononitrile methylene derivatives 3,4, respectively. Treatment of compound 4 with active methylene compounds afforded spiro cycl opentene derivatives 5(a-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 b romide or benzylidenemalononitrile furnished oxathiol-2-ylidene and pyridin ethione derivatives 13,14, respectively The dibromo derivative 16 was react ed with CS2 and active methylenes or malononitrile to obtain spiro dithieta nes 17(a-e) and 4-dicyano-methlyene derivative 22, respectively. Compounds 17 underwent a cycloaddition reaction with thioglycolic acid, N-phenylbenzo hydrazindoyl bromide, 2,5-dimethylfuran and 1- phenyl-3,5-pyrazolidinedione to give cycloadducts 18-21, respectively. Treatment of o-aminothiophenol o r o-phenylenediamine with the dicyano compound 22 leads to the formation of spiro thiazepine or spiro diazine derivatives 23(a,b). The arylidene deriv atives 24 was reacted with S,S-acetals, N,S-acetals or ammonium dithiocarba mate to afford dithiane, oxazine or pyrazolodithiocarbamate derivatives 25- 29, respectively. Chemoselective cyclization of compound 29 with H2SO4, NaO H or MeI gave compounds 30-32, respectively. Benzopyrano, derivatives 34,36 were obtained through the reaction of compound I with a mixture of thioure a, triethyl orthoformate and ethyl cyanoacetate or with cyanoketene S,S dia cetals, respectively.