New sesquiterpene esters and alkaloids from Euonymus japonicus: the ‘Ejap’ series. X-Ray molecular structures of Ejap-2, -3, -4, -5, -6, and -10

Abstract

Nine new sesquiterpenoid esters (Ejap-2, -3, -4, -6, -7, -10, -12, -13, and -14) have been isolated from Euonymus japonicus, besides a known compound (Ejap-5). Structures of the isolated substances were deduced from 1 D, as well as 2D COSY and NOESY, ¹H n.m.r. and mass spectra. The position of the benzoyl groups among the other esterifying moieties was located by X-ray diffraction for Ejap-2, -3, -4, -5, -6, and -10. Among the sesquiterpene cores, 8-deoxypolyalcohol C, 8-epi-polyalcohol C, 9-epi-alcohol A, and 4,12-dideoxyeuonyminol have been obtained in neither a synthetic nor a natural product until now.