Synthesis of some benzothiazole and benzothiazine derivatives with expected biological activity

Abstract

This work illustrates the versatile role of benzothiazolone and benzothiazinone moieties in the synthesis of different heterocyclic systems from readily obtainable materials and evaluation of their antifungal and antibacterial activities. The work can be divided into three main parts:- i- First part: deals with reactions of benzothiazolone derivative ii- Second part: deals with reactions of benzothiazinone derivative iii- Third part: antimicrobial evaluation i- First part: Different reactions of benzothiazolone derivative. Thiation of 5,6-dimethoxy-3H-benzothiazol-2-one afforded 5,6-dimethoxybenz[d]thiazole-2(3H)-thione (I), which was alkylated with different alkyl halides such as: methyl or ethyl iodide and / or bromo ethylacetate to give the corresponding S-alkyl derivatives IIa-c. Direct reaction of the benzothiazolone derivative with different alkyl halides such as: ethyl iodide /bromo propan/ iodo hexane/ iso butyl bromide/ ethyl 3- bromopropanoate and chloroacetone led to the formation of the corresponding N-alkyl derivatives IIIa-d, IV, V, respectively. The target compound, propanhydrazide derivative VI was constructed by hydrazinolysis of the propanoate compound IV by hydrazine hydrate in boiling ethanol [cf. scheme 1].