The density functional calculations (B3LYP) with 6-31G* basis set on conformers arising from s-cis-6a and s-trans-6b isomers are performed for the gaseous state as well as the solution in CHCl₃ employing reaction field Onsager model. The attention was paid primarily to the stretching vibrations of CO groups. Since the assignment of the carbamate and ethoxy CO stretching vibrations predicted from IR experimental spectra gives reverse order than the order calculated at B3LYP/6-31G* level in gaseous state as well as in CHCl₃ solution, the model of specific interaction has been examined. The associates between solute and solvent molecules and the dimer between two molecules formed through hydrogen bonds were treated. The model of dimer turned out to be more realistic.