Process for the preparation of alkyl Esters of bendamustine, bendamustine, and their derivatives.

摘要

Process for the Preparation of Alkyl Esters of Bendamustine, Bendamustine, and Their Derivatives The present invention relates to a process for the preparation of alkyl ester of bendamustine, bendamustine, as well as derivatives thereof. By the process according to the invention, the preparation of such compounds is possible in reproducible high yield. To this end, esters containing hydroxy groups are employed as starting materials, the hydroxyl groups of which are simply substituted by halogen groups. Such substitution is possible in the presence of (i) oxalyl chloride and (ii) n-dialkylformamide, dialkyl acetamide or dimethyl sulfoxide. In a subsequent reaction, the resulting esters may be hydrolyzed to form acid.