PROCESS FOR PREPARING AND PURIFYING 9-(2,6-DIHALOBENZYL)-ADENINES

摘要

Alkali metal salts or alkaline earth metal salts of adenine are alkylated with a 2,6-dihalobenzyl halide and with the production of a mixture of isomers of (2,6-dihalobenzyl)adenines, which consist to at least 70 % by weight of 9-(2,6-dihalobenzyl)adenines. The alkylation is carried out in a solid/liquid or liquid/liquid two-phase system. 9-(2,6-Dihalobenzyl)adenines, which are practically free of 3-isomers, are prepared from the isomeric mixture which is obtained by subjecting this mixture to a transalkylation in the presence of concentrated sulphuric acid and a carbenium ion acceptor. A further process for preparing 9-(2,6-dihalobenzyl)adenines, which are practically free of isomers, is based on first preparing a mixture of isomers of 9-(2,6-dihalobenzyl)adenines and then subjecting this mixture to an extraction with dilute mineral acid and then carrying out a transalkylation in the presence of concentrated sulphuric acid and a carbenium ion acceptor. The 9-(2,6-dihalobenzyl)adenines, which are practically free of 3-isomers, may be used for the therapy and prophylaxis of coccidiosis.