| 摘要 |
1306958 Substituted cobamides PIERREL SpA 2 Sept 1971 [30 Sept 1970] 46545/70 Heading C2V In a process for the preparation of α-(5,6- dimethylbenziminazolyl) - methyl - cobamide a solution of α-(5,6-dimethylbenziminazolyl)- hydroxy-cobarnide is exposed to white light while being reduced with stannous chloride in an inert atmosphere, the resulting solution under nitrogen and away from light is passed through an anionic exchange resin to remove impurities, then reacted with a methyl halide to obtain the methyl derivative which is absorbed on a non-ionic resin in a column, eluted and the final product crystallized from the eluate. An example is given. |
