Boron tribromide → 3-(3-Fluoro-4-hydroxyphenyl)-7-hydroxy-1-naphthonitrile

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Reaction Steps

In a highly preferred process of this invention, 3-Bromo-7-methoxy-1-naphthonitrile (6) is coupled with 3-fluoro-4-methoxyphenylboronic acid, which is commercially available, under the well-known Suzuki condition using sodium bicarbonate and catalytic amount of dichloro-bis(triphenylphosphine) palladium (II) in a mixture of water and 1,2-dimethoxyethane to give 3-(3-fluoro-4-methoxyphenyl)-7-meythoxy-1-naphthonitrile (8); typically the yield is approximately 98% with about 95%+HPLC purity. Finally, in this highly preferred process 3-(3-fluoro-4-methoxyphenyl)-7-methoxy-1-naphthonitrile (8) is demethylated using boron tribromide at about 83° C. and recrystallized from a mixture of water and ethanol to give 3-(3-fluoro-4-hydroxyphenyl)-7-hydroxy-1-naphthonitrile (1), typically in about 73% yield with 99%+HPLC purity.

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