Process for the preparation of alpha - bromo ketones substantially free of dibromuros

摘要

There is described a process for the production of theophylline derivatives of the formula IMAGE I where T is the theophyllinyl-(7)-residue, Alk is a straight or branched alkylene chain having 2 to 4 carbon atoms, R is hydrogen or a methyl group, n is 1 or 2 with the proviso that two hydroxy groups of the phenyl ring cannot be in the 3,4-positions by reacting an aminoalkyltheophylline of the formula IMAGE II with a bromoketone of the formula IMAGE III where R' is a lower alkyl group and the two -OCOR' groups of the phenyl ring cannot be in the 3,4 positions to an intermediate compound of the formula IMAGE IV and subsequently hydrolytically splitting off the R'CO protective group wherein the bromoketone of formula III is produced free of dibromide by bromination of a ketone of the formula IMAGE V followed by treatment with a lower trialkyl phosphite.