From tubers of Corydalis cava (L.) Schweigg. & Korte (C. tuberosa DC.) and C. nobilis Pers., Fumariaceae: Gadamer et al., Arch. Pharm. 265, 675 (1927); Manske, Can. J. Res. 18B, 288 (1940). Structure: Spth, Burger, Ber. 59, 1486 (1926). Synthesis of dl-form: Govindachari et al., ibid. 92, 1654 (1959). Configuration: Corrodi, Hardegger, Helv. Chim. Acta 39, 889 (1956).