Found in the shell of ripe poppyseed capsules: Wrede, Arch. Pharmacol. 184, 331 (1937); Baumgarten, Christ, Pharmazie 5, 80 (1950); Pfeifer, Weiss, ibid. 10, 658 (1955); from opium prepns: Pfeifer, Arch. Pharm. 290, 209 (1957). Preliminary stereochemical studies: Battersby, Spenser, J. Chem. Soc. 1965, 1087. Revised stereochemistry: Blaha et al., Collect. Czech. Chem. Commun. 29, 2328 (1964); Snatzke et al., Tetrahedron 25, 5059 (1969).