NOVEL SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL SCREENING OF 6-SUBSTITUTED 2-MERCAPTO BENZOTHIAZOLES

Anil B. Chidrawar*

ABSTRACT

The synthesis of 6-substituted 2-mercapto benzothiazoles was carried out by action of ammonium thiocyanate and bromine on p-substituted anilines (1) to afford 6-substituted 2-aminobenzothiazoles (2) as reported in the literature. This upon treatment with aqueous potassium hydroxide under reflux conditions gave potassium salt of 2-amino thiophenol (3). This mixture was then diluted with water, filtered and 5N acetic acid was added with vigorous stirring and until it becomes acidic. Yellow crystals of substituted 2-amino thiophenols (4) were filtered off, washed with cold water and dried. These thiophenols (4) were further treated with CS2 and potassium hydroxide in ethanol under reflux condition to provide the potassium salt of 2-mercapto benzothiazoles (5), which upon acidification with 1M HCl affords the 6-substituted 2-mercapto benzothiazoles (6a-c). The structures for the synthesized compounds are assigned on the basis of IR, 1HNMR and Mass spectral studies.

Keywords: Ammonium thiocyanate, 2-amino thiophenol, potassium hydroxide, 2-mercapto benzothiazoles.