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 7 H ‐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 .