7-Chloroalkoxyisoflavones (10-26) have been prepared by chemoselective-in the case of 5,7-dihydroxyisoflavones also regioselective-alkylation of hydroxyisoflavones (3-9) with alpha-bromo-omega-chloroalkanes. Compounds 10-26 were allowed to react either with 2',4'-dihydroxy-3'-n-propylacetophenone (1) or with 2-ethoxycarbonyl-7-hydroxy-8-n-propylchromone (2) to afford bridged isoflavone derivatives 27-51 with methylene spacers of various length. Carboxylic acid ethyl esters 43-51 have been saponified to obtain the carboxylic acids 52-60.
SZABO V.; BORBELY S.; DARBAI M., MAQY. KEM. FOLYOIRAT <MGKF-A3>, 1975, 81, NO 7, 311-313