Potent seed germination stimulant for the root parasite, witchweed, Striga lutea Lour. isolated from root exudates of cotton, Gossypium hirsutum L.: C. E. Cook et al., Science 154, 1189 (1966). Structure: eidem, J. Am. Chem. Soc. 94, 6198 (1972). Crystal structure: P. Coggan et al., J. Chem. Soc. Perkin Trans. 2 1973, 465. Synthesis: J. B. Heather et al., J. Am. Chem. Soc. 98, 3661 (1976); of (±)-form: G. A. MacAlpine et al., Chem. Commun. 1974, 834; eidem, J. Chem. Soc. Perkin Trans. 1 1976, 410. Synthesis of analogs: A. W. Johnson et al., ibid. 1981, 1734. Witchweed seed germination stimulating activity: A. L. Hsiao et al., Weed Sci. 29, 101 (1981); A. B. Pepperman et al., ibid. 30, 561 (1982).