Fused Heterocycles. IV. Synthesis of 7-(o-Hydroxyphenyl)-3,5-dimethyl-7,8-dihydro-6H-isoxazoloazepines

Article abstract of DOI:10.1246/bcsj.54.3617

Michael addition of acetylacetone to 3-methyl-4-nitro-5-(o-hydroxystyryl)isoxazoles gives 4-(o-acetoxyphenyl)-5-(3-methyl-4-nitro-5-isoxazoyl)-2-pentanones (4).Reductive cyclization of 4 with tin(II) chloride and concentrated hydrochloric acid leads to 7-