Process for preparing substituted 2,3-dihydrobenzofuran

摘要

A process is provided for preparing a substituted 2,3-dihydrobenzofuran of the general formula in which Ra is hydrogen, halogen, alkyl, straight or branched having from 1 to 4 carbon atoms, aryl, alkaryl, -OH, -OR3, -N(Rd)2, where R3 and Rd are alkyl, straight or branched having from 1 to 4 carbon atoms; Rb is alkyl, straight or branched, having from 1 to 6 carbon atoms, aryl, alkaryl; and Rc is hydrogen or the same as Rb, by the rearrangement of a 1,1-bis(2-hydroxybenzene) alkyl and/or aryl-ethane, in the presence of catalytic amounts of a mineral acid or organic acid such as phosphoric, sulfuric or p-toluenesulfonic, at elevated temperatures from 180 DEG to 250 DEG C., and withdrawing the resulting products from the reaction mixture as they are formed. The starting 1,1-bis(2-hydroxybenzene) alkyl and/or aryl-ethane compounds may be obtained by the catalyzed reaction of a substituted biphenol with an aldehyde. The substituted 2,3-dihydrobenzofurans are useful in the manufacture of pesticides.