Antitrypanosomal antibiotic produced by Streptomyces calvus. The first naturally occurring derivative of a fluoro sugar. Isoln and activity studies: Thomas et al., Antibiot. Annu. 1956-1957, 716; Hewitt et al., ibid. 722. Partial structure: Waller et al., J. Am. Chem. Soc. 79, 1011 (1957). Revised formula and structure: Morton et al., ibid. 91, 1535 (1969). Synthesis: Jenkins et al., ibid. 93, 4323 (1971).