Double cone-like crystal form of 2-amino-6-chloropurine and preparation

摘要

The present invention is directed to a method for preparing 2-amino-6-chloropurine having a double cone-like crystal form, comprising the steps of: (A) suspending 2-amino-6-chloropurine having an acicular or irregular-shaped crystal form in a liquid consisting essentially of water having a pH of from 3 to 10; and (B) heating the resulting suspension at a temperature of from 70 DEG to 100 DEG C. to complete the double cone-like crystal form conversion.