NEW POLYHETEROPOLYCYCLIC RING SYSTEMS PART XXV. SYNTHESIS OF STEROID-TYPE COMPOUNDS DERIVED FROM 5,5-DIMETHYL- 2,3,5,6-TETRAHYDRO-4H-THIOPYRANO [3,2-g]-BENZTHIADIAZOLE-4-ONE

Abstract

The synthesis of the tricyclic ketone, 5,5-dimethyl-2,3,5,6-tetrahydro-4H-thiopyrano[3,2-g] [1,2,3] benzthiadiazole-4-one (V) starting with dimedone is described. V served as the key intermediate for the total synthesis of the hitherto unknown 9,10-dihydro-9,9-dimethyl-5H[1,2,3] thiadiazolo-[4′,5′:4,5] thiopyrano [3,2-g][1,2,3]benzothiadiazole (VIII),¹ 9,10-dihydro-9,9-dimethyl-5H-isoxazolo[4′,5′:4,5]thio-pyrano[3,2-g][1,2,3]ben-zothiadiazole (IX) and 9,10-dihydro-9,9-dimethyl-8N-phenyl-5H-pyrazolo-[4′,5′ :4,5]thiopyrano[3,2-g]-[1,2,3]benzothiadiazole (X).