PROCEDEU PENTRU PREPARAREA UNOR DERIVATI DE ALFAERGOCRIPTINA

摘要

A process for the production of a compound of formula I wherein R1 is carboxyl, alkoxy- (C1-5)carbonyl, amido, alkyl(C1-5)amido, di(alkyl(C1-5))amido or an amido radical of formula II wherein Ra is alkyl(C1-4), Rb is alkyl(C1-4) or benzyl, and R2 is hydrogen or alkyl(C1-4), and either R3 is hydrogen and R4 is hydrogen or alkoxy(C1-4> or R3 and R4 together are a single bond, is characterised in that a compound of formula III wherein R1 to R4 are as defined above, is brominated with a bromine complex of 3-bromo-6-chloro-2-methyl- imidazo[1,2-b]pyridine having the formula IV: