Investigation of heterocycles containing nitrogen or sulfur. 47. Reactions of 1,2-dioxo-3a-alkyl-4,7-dichloroxazolidino [3,2-f]pyrido[2,3-b]-1,4-thiazines with saturated cyclic amines. synthesis and structure of derivatives of 1,2-dihydrothiazolo[5,4-b]pyridine
It has been established spectroscopically that 1-N-oxalamides of 2-acyl-5-chloro-1,2-dihydrothiazolo[5,4-b] pyridine are formed in the reaction of 4,7-dichloroxazolidino[3,2-f]pyrido[2,3-b]-1,4-thiazines with morpholine, piperidine and pyrrolidine. The products are a mixture of amide conformers in solution. The reaction intermediate 2-(1-chloro-2-oxobutylthio)-3-pyrrolidinooxamoyl-6-chloropyridine has been isolated and characterized. A proposed reaction scheme is presented.