Synthesis of 3-(trifluoromethyl)benzo[c][1,6]naphthyridines from substituted 4H-pyran-4-ones via 4-amino-5-aryl-2-(trifluoromethyl)pyridines

Article abstract of DOI:10.1016/S0040-4020(00)00637-2

The cyclization of acylated 4-amino-5-aryl-2-(trifluoromethyl)pyridines under the action of P₂O₅/POCl₃ smoothly afforded 3-(trifluoromethyl)benzo[c][1,6]naphthyridines in good yields. Intermediate aminopyridines were synthesized in a two-step sequence from the corresponding 4H-pyran-4-ones, which were prepared by reaction of 2-acetyl-2-aryloxiranes and 4-dimethylamino-3-(4-methoxyphenyl)-3-buten-2-one with ethyl trifluoroacetate under basic conditions. (C) 2000 Elsevier Science Ltd.