Process for preparing 3-substituted 2(3H)-benzothiazolones or 2(3H)-naphthothiazolones

摘要

A process for the manufacture of a 2(3H)-benzothiazolone compound substituted in 3-position, or of a 2(3H)-naphthothiazolone compound substituted in 3-position which comprises treating a 2(3H)-iminobenzothiazoline compound substituted in 3-position or a 2(3H)-naphthothazoline compound substituted in 3-position with an alkali metal hydroxide or alkaline earth metal hydroxide in a solvent or diluent stable to alkalis, in the absence of water or with substantial exclusion of water, and cyclizing the alkali metal or alkaline earth metal salt of the ortho-mercapto-N-phenyl- or -naphthyl-urea compound substituted at the nitrogen atom so formed, optionally without intermediate isolation, by treatment with an acid to give the 2(3H)-benzothiazolone compound substituted in 3-position or the 2(3H)-naphthothiazolone compound substituted in 3-position. The process furnishes the final products with high yield and purity; waste water problems are excluded by this process.