PROCESS FOR PREPARING SUBSTITUTED N-3-OXOALKYLTHIOAMIDES Russian patent published in 1996 - IPC

FIELD: organic chemistry. SUBSTANCE: process for preparing novel N-3-oxoalkylthioamides of general formula I: R¹-CO-CH₂-C(R³)(R³)-NH-CS-CH₂-R⁴, wherein R¹ is C₁-C₄-alkyl; R² is hydrogen or C₁-C₄- alkyl; C₆ is hydrogen, C₁-C₄-alkyl or phenyl; C₄ is hydrogen, C₁-C₄-alkyl or phenyl which have biological activity can be used for syntheusing biologically active compounds. Process comprises subjecting N-3-oxoalkylamides of general formula II: R¹-CO-CH₂-C(R³)(R³)-NH-CO-CH₂-R⁴ wherein R₁-R⁴ are as defined above, to intramolecular cyclization using HClO₄ in acetic anhydride and reacting the resulting 6-acetoxy-5,6-dihydro-4H-1,3-oxazinium perchlorates of general formula III: wherein is as defined above, with sodium hydrosulfide solution in methanol or dimethylformamide. EFFECT: more efficient preparation process.