Obtained from cadinene and other sesquiterpenes or sesquiterpene alcohols by dehydrogenation: Ruzicka, Meyer, Helv. Chim. Acta 4, 505 (1921); Ruzicka, Stoll, ibid. 7, 84 (1924). Synthesis: Ruzicka, Seidel, ibid. 5, 369 (1922); Barnett, Cook, J. Chem. Soc. 1933, 22; Johnson, Jones, J. Am. Chem. Soc. 69, 792 (1947); Kohli et al., Experientia 28, 131 (1972).