A process for the preparation of 2,4-dimethyl-3,5-bisalkoxycarbonylpyrrole is described, in which an acetoacetic alkyl ester is nitrosated to give the 2-nitrosoacetoacetic alkyl ester, the nitroso compound is reduced using hydrogen in the presence of a noble metal catalyst to give the amine, and the resulting amino compound is condensed without isolation in the presence of the corresponding non-nitrosated acetoacetic alkyl ester to give the 2,4-dimethyl-3,5-bisalkoxycarbonylpyrrole. The process makes it possible to work under conditions which are milder than in the prior art and to avoid the formation of by-products.
本发明描述了一种制备2,4-二甲基-3,5-双烷氧羰基
吡咯的方法,其中将
乙酰乙酸烷基酯亚硝化以得到2-亚硝基
乙酰乙酸烷基酯,使用
贵金属催化剂在
氢气存在下还原亚硝化合物以得到胺,并在相应的未亚硝化
乙酰乙酸烷基酯的存在下,将所得的
氨化合物在不分离的情况下缩合,以得到2,4-二甲基-3,5-双烷氧羰基
吡咯。该方法使得工作条件比现有技术更温和,并避免了副产物的形成。