反应详情

9-(2'-Hydroxy-3',4'-dimethoxy-6'-methylbenzoyl)nonanoic acid (formula II-1 wherein R=H3CO, X=H, Y=OH, n=8, in the free form) (0.197 part) was dissolved in methanol saturated with hydrogen chloride gas (7 volume parts) and the solution was stirred at room temperature for 20 minutes. The methanol was distilled off under reduced pressure and the residue was recrystallized from hexane-diethyl ether. The procedure provided methyl 9-(2'-hydroxy-3',4'-dimethoxy-6'-methylbenzoyl)nonanoate (formula II-1 wherein R=H3CO, X=H, Y=OH, n=8, in the form of methyl ester) (0.195 part) as colorless needles melting at 49°-53° C.

1. distillationThe methanol was distilled off under reduced pressure
2. customthe residue was recrystallized from hexane-diethyl ether