反应详情

The electrophilic fluorination of compound IV can be performed by passing trifluoromethyl hypofluorite into a stirred mixture of the compound in Freon at -78° C. The reaction is monitored frequently by thin layer chromatography to avoid over-fluorination. The crude product from the reaction is purified by column chromatography to provide 1-(3-fluoro-2,6-dimethoxyphenyl)propan-1-one V which is then reduced with borane in the presence of boron trifluoride in boiling tetrahydrofuran to give 1-fluoro-2,4-dimethoxy-3-propylbenzene VI in excellent yield. Acylation of V with an alkanoyl chloride under conventional Friedel-Crafts, conditions provides a compound of general structure VII which on treatment with boron tribromide in methylene chloride at -78° C. is demethylated to yield the afore-mentioned 1-(2,4-dihydroxy-5-fluoro-3-propylphenyl)alkan-1-one of general formula VIII.

1. additioninto a stirred mixture of the compound in Freon at -78° C
2. customThe crude product from the reaction is purified by column chromatography