Microtropins J-P: 6’-O-(2”iS/i,3”iR/i)-2”-Ethyl-2”,3”-Dihydroxybutyrates of Phenolic Alcohol iamp;#223/i-D-Glucopyranosides from the Branches of iMicrotropis japonica/i

摘要

From the branches of Microtropis japonica (Celastraceae), seven phenolic alcohol glucosides, named microtropins J-P (1-7), were isolated. The 6-position of glucose was esterified with 2-ethyl-2,3-dihydroxybutyric acid. Microtropin K (2) was hydrolyzed under a mild basic condition to give methyl (2S,3R)-2-ethyl-2,3-dihydroxybutyrate, whose absolute structure was determined by the comparison of NMR data and the optical rotation value with that reported.