Unexpected Formation of 4-[(1-Carbamoyl-3-oxo-1,3-dihydro-2-benzofuran-1-yl)amino]benzoic Acid from 4-[(3-Amino-1-oxo-1<i>H</i>-2-benzopyran-4-yl)amino]benzoic Acid
Ricaurte Rodríguez,
Felipe Quiroga-Suavita,
Mónica Yadira Dotor Robayo
Affiliations
Ricaurte Rodríguez
Investigation Group in Heterocyclic Chemistry, Chemistry Department, Universidad Nacional de Colombia-Sede Bogotá, Carrera 30, Calle 45-03, Bogotá 111321, Colombia
Felipe Quiroga-Suavita
Investigation Group in Heterocyclic Chemistry, Chemistry Department, Universidad Nacional de Colombia-Sede Bogotá, Carrera 30, Calle 45-03, Bogotá 111321, Colombia
Mónica Yadira Dotor Robayo
Residuality and Environmental Destination of Pesticides in Agricultural Systems, Agronomy Department, Universidad Nacional de Colombia-Sede Bogotá, Carrera 30, Calle 45-03, Bogotá 111321, Colombia
With the aim of obtaining derivatives belonging to 2′,3′-diphenyl-3H-spiro[[2]benzofuran-1,4′-imidazole]-3,5′(3′H)-dione nucleus, we synthesized 4-[(3-amino-1-oxo-1H-2-benzopyran-4-yl)amino]benzoic acid (a 3,4-diaminoisocoumarine derivative), a known precursor of 4-[(1-carbamoyl-3-oxo-1,3-dihydro-2-benzofuran-1-yl)amino]benzoic acid (a phthalide–carboxamide-bearing system) by a novel methodology that we report here. The reaction conditions were optimized to afford the latter in 62% yield.
