(2-CHLORO-2-NITROETHENYL)BENZENES AS SYNTHONS: A GENERAL METHOD FOR THE PREPARATION OF 2,3-DIHYDRO-2-NITRO-3-PHENYL-4H-FUROBENZOPYRAN-4-ONES AND 3-PHENYL-4H-FUROBENZOPYRAN-4-ONES

Article abstract of DOI:10.1016/S0040-4020(01)89053-0

We describe a convenient and general method for the preparation of 2,3-dihydro-2-nitro-3-phenyl-4H-furo<3,2-c><1>benzopyran-4-ones from 4-hydroxycoumarin and (2-chloro-2-nitroethenyl)benzenes in the presence of potassium fluoride.Using the same starting materials and by replacing potassium fluoride with triethylamine the hitherto unknown 3-phenyl-4H-furo<3,2-c><1>benzopyran-4-ones are obtained in a one-pot procedure.