Prepn: GB 1119636; M. Hoffer, M. Mitrovic, US 3634446 (1968, 1972 both to Hoffmann-La Roche); K. Butler, ZA 6607466 (1968 to Pfizer), C.A. 71, 3384e (1969). Structure-activity relationship: K. Butler et al., J. Med. Chem. 10, 891 (1967). Activity studies as an antihistomonal agent: M. Mitrovic et al., Antimicrob. Agents Chemother. 1968, 445; M. Mitrovic, E. G. Schildknecht, Poult. Sci. 49, 86 (1970); as a growth promotant: W. L. Marusich et al., ibid. 98. Toxicity studies: eidem, ibid. 92.