From fruit of Evodia rutaecarpa Hook. & Thoms. and Hortia arborea Engl., Rutaceae: Asahina, Kashiwaki, J. Pharm. Soc. Jpn. 1915, 1293; Pachter et al., J. Am. Chem. Soc. 82, 5187 (1960). Structure: Y. Asahina, J. Pharm. Soc. Jpn. 1924, 1. Synthesis: Y. Asahina et al., J. Chem. Soc. 1927, 1708; T. Kametani et al., J. Am. Chem. Soc. 99, 2306 (1977); eidem, Chem. Pharm. Bull. 26, 1922 (1978); H. M"ohrle et al., Arch. Pharm. 313, 990 (1980); J. Bergman, S. Bergman, Heterocycles 16, 347 (1981). Simple synthesis: J. K"ok"osi et al., Tetrahedron Lett. 22, 4861 (1981). Synthesis under physiological conditions: Sch"opf, Angew. Chem. 50, 779, 797 (1937). Biosynthesis: M. Yamazaki et al., Tetrahedron Lett. 1966, 3221; 1967, 3317. Mass spec.: J. Tamas et al., Acta Chim. Acad. Sci. Hung. 89, 85 (1976).