Novel High Yielding Syntheses of Benzodifuranone Dyes Bearing Nitrogen Substituents at the 4-Position of a Pendent Phenyl Ring

Abstract

Otherwise inaccessible nitro benzodifuranone (BZDF) dyes are formed in good yield by treatment of 5-hydroxy-2-oxo-3-phenyl-2,3-dihydrobenzofuran either with 4NO₂-3-R-C₆H₃CBrClCO₂CH₃ (R = H, alkyl, aryl or CO₂CH₃) in acetic acid. High yielding reduction of the nitro to the amino BZDF is accomplished by catalytic hydrogenation over Pd or by NaBH₄ / SnCl₂.