2-METHYL-AND 2-DIMETYLAMINOQUINO[4,3-e]-1,2,4-THIADIAZINE 4,4-DIOXIDES-SYNTHESIS, STRUCTURE AND N-METHYLATION

摘要

Reaction of 4-chloro-3-quinolinesulfonyl chloride with acetamidine or with N,N-dimethyl-and N,N,N'-trimethylquanidine salts led directly or stepwise via 4-chloro-3-quinolinesulfonylguanidine (6a) to the title 2-substituted quino[4,3-e]-1,2,4-thiadiazine 4,4-dioxides (4, 7a, and 8). X-Ray studies proved that 2-methyl derivative 4 exists as the 1H-tautomer while 2-dimethylamino derivative 7a as the 6H-tautomer. Reaction of N-H derivatives 4 and 7a and the pyrido-1,2,4-thiadiazine analog 11a with CH3I/CH3OK/DMF system proceeded at the pyridine-ring nitrogen and led to 6-methylquino derivatives 5 and 7b or the 7-methylpyrido derivative 11b, respectively, as concluded from 2D ~1H-~(13)C NMR data.