Occurs as d-form in the root and whole plant of Papaver orientale L., Papaveraceae, collected in late autumn. Isoln: Gadamer, Arch. Pharm. 249, 39 (1911). Structure: Bentley, Blues, J. Chem. Soc. 1956, 1732; Bentley, Dyke, J. Org. Chem. 22, 429 (1957). Synthesis of dl-form: Battersby, Brown, Proc. Chem. Soc. London 1964, 85; H. Hara et al., Chem. Pharm. Bull. 29, 1083 (1981). Synthesis of natural and racemic forms: Battersby et al., J. Chem. Soc. 1965, 4550. Biosynthesis: eidem, Chem. Commun. 1965, 230.