Amlodipine Impurity 1 Catalogue A236751 CAS 496024-43-2 M.W 391.85 M.F C20H22ClNO5 Specifications FAQs 5-ethyl 7-methyl 6-(2-chlorophenyl)-8-methyl-3,4,6,7-tetrahydro-2H- benzo[b][1,4]oxazine-5,7-dicarboxylate