Iridolactone isolated from the Argentine ant Iridomyrmex humilis Mayr., Dolichoderinae. Exhibits antibacterial and insect antifeedant activity. Isoln: Pavan, Ric. Sci. 19, 1011 (1949); Chim. Ind. (Milan) 37, 625 (1955); Fusco et al., ibid. 251, 958; Cavill et al., Aust. J. Chem. 9, 288 (1956); 10, 352 (1957). Synthesis: Korte et al., Tetrahedron 6, 201 (1959); Sisido et al., J. Org. Chem. 29, 3361 (1964); R. S. Matthews, J. K. Whitesell, ibid. 40, 3312 (1975); Y. Yamada et al., Chem. Lett. 1978, 1405; P. Callant et al., Tetrahedron 37, 2085 (1981). Stereochemistry: Korte et al., Ber. 94, 1952 (1961); McConnell et al., Tetrahedron Lett. 1962, 445; Büchi, Manning, Tetrahedron 18, 1049 (1962). Activity as bactericide and insecticide: M. Pavan, Z. Hyg. Infektionskrankh. 134, 136 (1952), C.A. 46, 9796f (1952).