The position of the carbonyl-stretching bands in the ir spectra of the desaurins, 2, 4-bis (acylmethylene)-and 2, 4-bis (carboxymethylene)-1, 3-dithetane derivatives, establishes that there is a strong interaction between the sulfur atoms and the carbonyl groups. This is considered to involve mainly conjugative interaction rather than interaction through space, although the latter may account for the abnormally weak intensity of the carbonyl- ...