Gefitinib O-Desmethyl Impurity Catalogue G420564 CAS 847949-49-9 M.W 432.88 M.F C21H22ClFN4O3 Specifications FAQs 4-[(3-Chloro-4-fluorophenyl)amino]-6-[3-(4-morpholinyl)propoxy]-7-quinazolinol