Selective pre-emergence herbicide. Prepn: C. Vogel, R. Aebi, DE 2328340; eidem, US 3937730 (1973, 1976 both to Ciba-Geigy). Synthesis of stereoisomers: B. T. Cho, Y. S. Chun, Tetrahedron: Asymmetry 3, 337 (1992). Metabolism: L. L. McGahen, J. M. Tiedje, J. Agric. Food Chem. 26, 414 (1978). ELISA determn: T. S. Lawruk et al., J. Agric. Food Chem. 41, 1426 (1993). Review: G. Chesters et al., Rev. Environ. Contam. Toxicol. 110, 1-74 (1989); of biological activity and field trials: H. R. Gerber et al., Proc. 12th Br. Weed Control Conf. 787-794 (1974).