Prepn. of alpha-alkylphenyl-alkanoic acids - from alkyl-benzaldehyde or -acetophenone via aldehyde

摘要

Prepn. of alpha-(4-alkylphenyl)alkanoic acid of formula (I) is carried out by (a) reacting the corresp. benzaldehyde or acetophenone derivs. (II) with ClCH2OEt in the presence of an alkylmagnesium halide in THF at low temp.; (b) treating the product (III) with an acid to form the corresp. alpha-(4-alkylphenyl)alkanol (IV); and (c) oxidising (IV) with NaClO3 in the presence of sulphamic acid in an aq. medium at room temp. In the formulae, R1 is 1-5C alkyl and R is H or Me. Cpds. (I) are used as anti-inflammatory antipyretic and analgesic agents. The process gives high overall yields (e.g. 66-72%).