| 摘要 |
The invention relates to a nitration method having the following principles: a phosgene species is converted with two equivalent silver nitrates into a double-mixed anhydride of carbonic acid and nitric acid, known here as carbonic acid dinitrate (I). Said operation is carried out in situ, and the formed dinitrate decomposes spontaneously. In addition to carbon dioxide, nitrate ions and nitronium ions are formed, said ions comprising electrophiles which are necessary for nitration. The solution which is used is acetonitrile, and is insignificant if the alcohol species is dissolved or suspended. The necessary equivalent silver nitrates are introduced into the system and optionally heated or cooled to the desired temperature. Subsequently, the acid chloride is introduced slowly, drop by drop or slowly little by little. Phosgene, diphosgene, triphosgene and chloroformic acid ester can be used as carbonic acid dichloride and monochloride, and their thiocarbonic acid analogues. A brown colouration and precipitated silver chloride display the formation of the carbonic acid reactants, said brown colouration rapidly discolouring due to an immediate reaction of the nitronium ions with the substrate with is to be nitrated. Towards the end of the addition of phosgene, the brown colouration remains for longer and longer until it no longer disappears. Then, it is stirred for another hour at room temperature. In the event of high acid-sensitive educts, non-nucleophilic nitrogen bases such as DBU can be added to the system in order to intercept the formation of nitric acid. |
