Convergent Approach for Commercial Synthesis of Gefitinib and Erlotinib

An efficient, economical and large-scale convergent synthesis of epidermal growth factor receptor- tyrosine kinase inhibitors gefitinib (1, Iressa) and erlotinib (2, Tarceva) approved by U.S. FDA for the treatment of non-small-cell lung cancer is described. The formation of 4-anilinoquinazolines are achieved in a simple one-pot reaction of suitable formamidine intermediates and substituted anilines involving Dimroth rearrangement, thereby avoiding the need to make quinazolin-4(3H)-one intermediates, which require a large experimental inputs. Using this process, we have produced drug candidates 1 with overall yield of 66% from 4-methoxy-5-[3-(4-morpholinyl) propoxy]-2-nitrobenzonitrile (3) and 2 with 63% from 4,5-bis(2-methoxyethoxy)-2-nitrobenzonitrile (6) on a multigram scale.