Patents

The invention describes an improved and advantageous process of preparation of trans 3,4-diarylchroman and similar derivatives thereof, useful as anti-fertility, anti-osteoporotic and breast cancer drugs. Condensation of arenes with 2,2-dialkyl-3-aryl chromene in the presence of a Lewis acid furnishes trans -3,4-diaryl-2,2-dialkylchroman exclusively. Thus trans-2,2-dimethyl-3-phenyl-4-(4-hydroxyphenyl) chroman, the precursor of Ormeloxifene is obtained in excellent yield by hydroarylation of phenol with 2,2-dimethyl-3-phenyl chromene.