| 主权项 |
1. A method for making magnolol (5,5′-diallyl-biphenyl-2,2′-diol) or tetrahydromagnolol (5,5′-dipropyl-biphenyl-2,2′-diol), comprising
i) methylating biphenyl-2,2′-diol using dimethyl sulfate, to obtain 2,2′-dimethoxy-biphenyl; ii) brominating the 2,2′-dimethoxy-biphenyl to obtain 2,2′-dimethoxy-5,5′-dibromo-biphenyl; iii) alkylating the 2,2′-dimethoxy-5,5′-dibromo-biphenyl with allyl bromide to obtain 2,2′-dimethoxy-5,5′-diallyl-biphenyl; iv) demethylating the 2,2′-dimethoxy-5,5′-diallyl-biphenyl by reaction with aluminium chloride and thiourea; v) recovering the 5,5′-diallyl-biphenyl-2,2′-diol thus obtained; and vi) optionally hydrogenating the 5,5′-diallyl-biphenyl-2,2′-diol in the presence of a metal catalyst and recovering the 5,5′-dipropyl-biphenyl-2,2′-diol thus obtained. |
