MICROWAVE ASSISTED SYNTHESIS OF BIOLOGICALLY ACTIVE 4-HYDROXY-7V-(PHENYLCARBONYL)-2H-1,2-BENZOTHIAZINE-3-CARBOHYDRAZIDE 1,1-DIOXIDE DERIVATIVES

• DOI: 10.4067/s0717-97072012000400031
• Publication Date: 2013-04-08T08:18:01Z
• Authors: MUHAMMAD ZAHEER; MUHAMMAD ZIA-UR-R...; SALMA RAHMAN; NAVEED AHMED; MUHAMMAD NAWAZ CH...
• Keywords: Benzohydrazide; Anti-fungal; Carbohydrazides; 1,2-Benzothiazine; Microwaves; Anti-bacterial; 01 natural sciences; 0104 chemical sciences; 3. Good health

ABSTRACT Microwave assisted synthesis of a series of 4-hydroxy- N ’-(phenylcarbonyl)-2 H -1,2-benzothiazine-3-carbohydrazide 1,1-dioxides from sodium saccharin is reported. Sodium o-benzosulfimide was N -alkylated with ethyl chloroacetate followed by base catalyzed ring expansion to six membered 1,2-benzothiazine through Gabriel-Coleman type rearrangement yielding ethyl 4-hydroxy-2 H -1,2-benzothiazine-3-carboxylate 1,1-dioxide. It was later condensed with a series of benzohydrazides synthesized from various carboxylic acids to get the title compounds. All the synthesized compounds were subjected to preliminary evaluation for their biological activity against series of Gram positive, Gram negative bacteria and fungi. Some of the compounds showed marked activity against the selected microorganisms. Key Words : Microwaves; Benzohydrazide; Carbohydrazides; 1,2-Benzothiazine; Anti-bacterial; Anti-fungal. INTRODUCTION There is a need for development of clean chemical processes including synthetic procedures, catalysis and reaction conditions to reduce the environmental impact of chemical & pharmaceutical industry. To achieve this, innovative and unconventional synthetic procedures using water as solvent