Syntheses of potassium 1,1-dioxopyrido[4,3-e]-1,4,2-dithiazine-3-thiolate and its application to the synthesis of novel sulfonamides with potential biological activity

Potassium 1,1-dioxopyrido[4,3-e]-1,4,2-dithiazine-3-thiolate 2 has been synthesized and applied to the syntheses of 7H-1,1-dioxopyrido[4,3-e]-1,4,2-dithiazolium-3-thiolate 3 and 3-methylthiopyrido[4,3-e]-1,4,2-dithiazine 1,1-dioxide 4 which provided easy access to a variety of its 3-amino derivatives 5-10. Hydrazinolysis of 7, 8 and 10 afforded the corresponding 3-amino-2-(1,4-dihydro-4-thioxopyrid-3-ylsulfonyl)guanidines 11-13. Subsequent reaction of 12 with 4-chlorobenzaldehyde gave condensation product 14. 1,4-Dihydro-2-thioxopyridine-3-sulfonamide 15 was also prepared from the potassium salt 2 upon alkaline hydrolysis, whereas alkylation of 15 gave the appropriate S-substituted derivatives 16-19 or S,N-disubstituted compounds 20-21.