[Studies on the synthesis of dimethyl 4-hydroxy-4'-methoxy-5,6,5',6'-bismethylenedioxy biphenyl-2,2'-dicarboxylate--an essential metabolite of biphenyl diester].

This paper reports the synthesis of dimethyl 4-hydroxy-4'-methoxy-5,6,5',6'-bismethylenedioxybiphenyl-2,2'-dica rboxylate (II). Various conditions for bromination were tried to find the best one for synthesis of the key intermediate compound 6. After Ullmann condensation of 6 with 8 and hydrogenolysis, the title compound II was obtained. It was proved to be identical with the isolated metabolite of biphenyl diester by spectral data.