Syntheses of some 2-( 4'-Acetamido-3'-nitrobenzoyl)-coumaran-3-ones

P. G. Department of Chemistry, Bhagalpur University, Bhagalpur-812 007 Manuscript received 29 June 1990, revised 13 March 1992, accepted 23 March 1992 Syntheses of several 2 (4' acetamido-3'-nitrobenzoyl)coumaran-3-ones by two routes have been described. In one, the corresponding esters were converted to the related 1 3.diketones which on bromination directly produced 3- bromoflavones. Refluxing of the bromoflavones with ethanolic KOH gave coumaran-3 ones. In the second route the corresponding esters were brominated using CuBr2 to yield α-bromoacetophenones which on Baker-Venkataraman transformation directly afforded the desired product. The structure of the aurones were confirmed by elemental analysis and spectral data