New furanoditerpenoids from Croton jatrophoides

Four furanoditerpenoids were isolated from roots of Croton jatrophoides (Euphorbiaceae) collected in Tanzania. In addition to the known compounds penduliflaworosin and teucvin (mallotucin A), a new teucvin isomer, which was named isoteucvin, and a furanoditerpenoid with a new skeleton, for which the name jatrophoidin was adopted, were isolated. Their structures were elucidated by spectroscopic methods such as ESI-MS and NMR, including 1H-, 13C-, and two-dimensional NMR. The crystal structures of isoteucvin and jatrophoidin were solved using single-crystal X-ray diffraction, by which we also established the absolute configuration of jatrophoidin. The refined crystal structure of isoteucvin has the same (absolute) configuration as jatrophoidin, although the X-ray diffraction data of isoteucvin were not conclusive with respect to the absolute configuration.