摘要:
Process for the preparation of / D-a-amino-p- hydrox- yphenylacetamido/ groups containing penicillanic acid and cephalosporanic acid derivatives, comprising the acylation of a compounds of the formulae: and/or or and/or wherein R 1 , R 2 , and R 3 represent the same or a different group and may be selected from a lower alkyl, benzyl, cycloalkyl or phenyl-group and preferably lower alkyl and more preferably a methyl group and wherein X represents a residue selected from the group consisting of hydrogen, acetoxy or a fivemembered heterocyclic thio residue, containing heteroatoms selected from nitrogen, oxygen and/or sulphur and optionally substituted by lower alkyl and wherein an eventually present -NH- radical has optionally been silylated, which compound is previously prepared by the reaction of -6-aminopenicillanic acid or 7-aminocephalosporanic acid or its 3-methyl modifications with at least one equivalent and preferably about 2 with respect to 6-APA, 7-ACA or 7-ADCA and about 3 equivalents with respect to other 3-methyl modifications of 7-ACA of a tri(lower)alkyl silyl groups supplying agent in a dry inert, water insoluble solvent, such as methylene chloride, by rapid mixing of a pre-cooled solution of the compound of formula I-IV with a pre-cooled reaction mixture of at least an equimolar amount of a compound of the formula wherein R 4 represents lower alkyl and preferably methyl, R 5 represents hydrogen or lower alkyl and preferably methyl, R 6 represents lower alkoxy and preferably methoxy and R 7 represents lower alkoxy and preferably methoxy, previously prepared from the corresponding Dane salt and an acid chloride under anhydrous conditions in the presence of a tertiary amine as catalyst, such as N-methylmorpholine in a dry, inert, water insoluble, organo solvent such as methylene chloride mixed with a cosolvent or methyl isobutylketone or tetrahydrofuran optionally mixed with a cosolvent, and the continuation of the reactior at a temperature of -10°C or lower and preferably from 2°C to 30°C whereafter the desired compound is recovered by usual methods.
摘要:
Improved process for the preparation of brominated cephalosporanic derivatives, wherein a desacetoxy-3-cephem sulphoxide of general formula wherein R 1 represents an acylamido group and R 3 represents a group protecting the carboxy radical, is brominated in manner known per se and a compound of general formula in the reaction mixture or separated from such a reaction mixture is debrominated in the presence of a hydrogen donor and the 3-bromomethyl-3- cephem derivative of the general formula thus produced is recovered.