| 主权项 |
1. A method of preparing semi-synthetic oximes, comprising:
a) applying an extract of S. nutans and/or X. poposum plants to column chromatography and thin layer chromatography, to obtain a metabolite of formula: wherein R corresponds to H, OH or methyl; R′ and R″ corresponds to H, methyl, propyl, propylene, 3-methylbutyl-2-ene, or R′ y R″ together form a system derived from dihydrobenzofuran, b) heating under reflux between 100 mg to 400 mg of starting metabolite with a mixture of from 30 to 250 mg of hydroxylamine hydrochloride dissolved in 5 mL of ethanol and from 150-400 μL of pyridine at 40° C.-60° C. for 18-38 hours; c) separating the organic phase from the reaction mixture by liquid-liquid extraction using an organic solvent such as dichloromethane, chloroform, ethyl acetate or ethyl ether; d) concentrating the organic phase on a rotary evaporator; e) purifying the oxime by silica gel column chromatography, wherein each column progress is monitored by thin layer chromatography. |
