| 摘要 |
1336954 2-Aminobenzothiazole and N-alkyl derivatives thereof BAYER AG 8 Dec 1971 [8 Dec 1970] 56979/71 Heading C2C A process for the preparation of 2-aminobenzothiazole and N-alkyl substituted derivatives thereof, comprises reacting 2-mereaptobenzothiazole, or a salt thereof, at a temperature of from 80‹ to 240‹ C. at an elevated pressure and in an aqueous medium with at least the stoichiometric amount of (i) an amine of the formula wherein R and R<SP>1</SP> are hydrogen atoms or (C 1 -C 6 ) alkyl groups, or together represent the ring members required to complete a 5-, 6- or 7-membered heterocyclic ring, which if it is a 6-membered ring may also contain an oxygen or sulphur atom or a (C 1 -C 6 ) alkyl substituted nitrogen atom as additional hetero atoms, and (ii) sulphur dioxide, in the presence of a salt, oxide or hydroxide of an alkali metal, alkaline earth metal, copper, silver, gold, zinc, cadmium or mercury, the said salt being of an acid having a pK value greater than 1À92. |
