Direct synthesis of 2,4‐diaminoquinazolines from 2‐fluorobenzonitriles

Abstract

Abstract In a search for new methods for preparing 2,4‐diaminoquinazolines having a diversity of substituents in the benzenoid ring, it was found that the reaction of 2,6‐difluorobenzonitrile with guanidine carbonate gave 2,4‐diamino‐5‐fluoroquinazoline in excellent yield. Extension of this approach to other 2‐fluorobenzonitriles, some of which were elaborated for the first time, showed that this reaction possesses considerable generality. The cyclization was successful even when electron donating groups were present at position six. Only in two cases where a primary or secondary amino group was also present ortho to the cyano group was this transformation unsuccessful.