申请人:Sandoz Ltd.
公开号:US04609731A1
公开(公告)日:1986-09-02
The present invention provides an improved process for the production of a compound of formula I ##STR1## wherein R.sub.1 is carboxyl, alkoxy(C.sub.1-5)carbonyl, amido, alkyl(C.sub.1-5)amido, di(alkyl(C.sub.1-5)amido or an amido radical of formula II ##STR2## wherein R.sub.a is alkyl(C.sub.1-4), R.sub.b is alkyl(C.sub.1-4) or benzyl, and R.sub.2 is hydrogen or alkyl(C.sub.1-4), and either R.sub.3 is hydrogen and R.sub.4 is hydrogen or alkoxy(C.sub.1-4) or R.sub.3 and R.sub.4 together are a single bond, characterized in that a compound of formula III ##STR3## wherein R.sub.1 to R.sub.4 are as defined above, is brominated with a bromine complex of 3-bromo-6-chloro-2-methyl-imidazo[1,2-b]pyridazine.
本发明提供了一种改进的制备I式化合物的方法,其中R1是羧基,烷氧基(C1-5)羰基,酰胺,烷基(C1-5)酰胺,二(烷基(C1-5)酰胺)或式II中的酰胺基团:其中R a是烷基(C1-4),R b是烷基(C1-4)或苯甲基,R2是氢或烷基(C1-4),而R3是氢且R4是氢或烷氧基(C1-4),或R3和R4在一起形成单键。其特征在于,使用3-溴-6-氯-2-甲基咪唑[1,2-b]吡嗪的溴化复合物对式III的化合物进行溴化,其中R1至R4如上所定义。