Diterpenoid quinone methide with tumor-inhibitory properties. Isoln of naturally occurring (+)-form from Taxodium distichum Rich, Taxodiaceae: S. M. Kupchan et al., J. Am. Chem. Soc. 90, 5923 (1968). Structure: eidem, J. Org. Chem. 34, 3912 (1969). Total synthesis of the racemate: K. Mori, M. Matsui, Tetrahedron 26, 3467 (1970); T. Matsumoto et al., Bull. Chem. Soc. Jpn. 44, 2766 (1971); 50, 1575 (1977); D. L. Snitman et al., Tetrahedron Lett. 1979, 2477; R. V. Stevens, G. S. Bisacchi, J. Org. Chem. 47, 2396 (1982). Total synthesis of the (+)-form: T. Matsumoto et al., Bull. Chem. Soc. Jpn. 50, 266 (1977); R. H. Burnell et al., Can. J. Chem. 65, 775 (1987). Antitumor activity studies: Hanson et al., Science 168, 378 (1970).