The first isolation and crystal structure of a boron difluoro complex (isoflavone yellow). Biologically active intermediates produced during isoflavone synthesis

摘要

The yellow intermediate 4f produced during the reaction of the deoxybenzoin 3f with N,N'-dimethyl (chloromethylene) ammonium chloride in the presence of BF_3 centre dot Et_2O prior to the formation of the corresponding isoflavone was isolated for the first time and characterized by NMR, MS and single=crystal X-ray diffraction techniques. These yellow intermediates showed anticancer, nematicidal and mosquitocidal activities.