Synthesis of [1]benzopyrano[2,3-b]pyrrol-4(1H)-ones

Article abstract of DOI:10.1016/S0040-4020(97)10077-1

2-N-(Acylmethyl)aminochromones were prepared from 2-chlorochromone and α-amino ketones (hydrochloride or ketal derivatives) in ethanol/triethylamine. Their treatment with-acetic acid/pyrrolidine led to [l]benzopyrano[2,3-b]pyrrol-4(1H)-ones, which were subsequently functionalized in C2 by aromatic electrophilic substitution (acetylation, bromination or nitration).