From bark of Tiliarcora acuminata Miers, and T. racemosa Colebr., Menispermaceae. Isoln: Van Itallie, Steenhauer, Pharm. Weekbl. 59, 1381 (1922). Structure: Anjaneyulu et al., Chem. Ind. (London) 1959, 1119; Rao, Row, J. Org. Chem. 25, 981 (1960). Revised structure: Anjaneyula et al., J. Sci. Ind. Res. 21B, 602 (1962); eidem, Tetrahedron 25, 3091 (1969); M. Shamma, J. E. Foy, J. Org. Chem. 41, 1293 (1976). Abs config and biosynthesis: D. S. Bhakuni et al., Chem. Commun. 1978, 226.