Patent ID: 6891072

Claim:
A method for preparing dimer of a monohydroxy aromatic compound represented by formula: [II] wherein Y 1 and Y 2 may be same or different and each is selected from the group consisting of hydrogen atom, an esterified carboxyl group, a group of —(CONH)n-X (wherein X is an optionally branched and optionally substituted hydrocarbon group which may have an unsaturated bond, an optionally substituted aromatic group or a heterocyclic group having conjugated double bonds, n is an integer of 1 or 2); Q is selected from the group consisting of an optionally branched alkyl and alkoxy group of 1-6 carbon atoms, halogen atom, nitro group or nitroso group; and m represents an integer of 0-3; comprising carrying out an oxidative coupling reaction of the monohydroxy aromatic compound in N,N-dimethylformamide solvent in the presence of a copper (I) salt.