SYNTHESIS OF NEW [1,4]-BENZOTHIAZINE DERIVATIVES

A synthesis of new heterocyclic systems containing [1,4]-benzothiazine moiety has been established. the condensation of 2- aminothiophénol 1 with 2-chloroacetic acid lead to 3,4-dihydro-2h-[1,4]-benzothiazin-3-one 2. thereafter, the compound 2 is subjected to the action of benzaldehyde in the presence of an excess of sodium methoxide in dmf. this reaction led to the formation of 2-(benzylidene)-3,4-dihydro-2h-[1,4]-benzothiazin-3-one 3. then, nalkylation of the latter compound was accomplished using carbon chains halogenated under phase transfer catalysis conditions. the different products were obtained in good yields and their structures have been characterized by the usual spectroscopic methods.