From Lophophora williamsii (Lemaire) Coutl. (Anhalonium lewinii Henn.), Cactaceae: Kauder, Arch. Pharm. 237, 190 (1899); Spth, Becke, Monatsh. Chem. 66, 327 (1935). Structure: eidem, Ber. 67, 2100 (1934). Synthesis: Spth, Roder, Monatsh. Chem. 43, 93 (1922); Brossi et al., Helv. Chim. Acta 47, 2089 (1964); 49, 403 (1966). Biosynthetic studies: Kapadia et al., J. Am. Chem. Soc. 92, 6943 (1970). Review: Manske in R. H. F. Manske, H. L. Holmes, The Alkaloids vol. IV (Academic Press, New York, 1954) pp 8-14.