Testing a 3-oxo of bile acids derivatives with method of infrared spectroscopy which is integrated with Fourier transformation (FT-IR spectroscopy) is used to obtain information about the interactions between the solute and solvent.. The goal of the work is better inside into the possibility of creating intermolecular interactions of bile acids in tests of associations and only−associations of bile acids and their use for medical purposes. Synthesis was performed a 12a−hydroxy-3−oxo-5b−cholanoic acid in 4 synthetic stages from deoxycholic acid. We have investigated the potential interactions of the carbonyl groups of the methyl ester of 7a,12a−dihydroxy −3−oxo-5b−cholanoic acid and 3−oxo−12a−hydroxy-5b−cholanoic acid with various solvents using Guttman model, Kirkwood−Bayer-Magat model and the Linear relationship of solvation energy. During the test, the samples were placed in sodium chloride cuvette thickness of 0.057 and 0.116 mm. By recording the FT-IR spectra on the apparatus Thermo Scientific NEXUS 670 using a detector with deuterated triglicinsulfat in range of 2000 to 1600 cm−1, resolution from 2 cm−1 and using 50 scans performed, were obtained by the concentrations of Me−ester of 7a,12a−dihydroxy−3−oxo-5b−cholanoic acid and 3−oxo−12a−hydroxy−5b−cholanoic acid between 0.003 and 0.2 moldm −3 .The ester carbonyl group is more sensitive to interactions with solvents compared to carbonyl from keto group, because of less steric of protection of said carbonyl of the ester functional groups. This is a consequence of higher polarity, which owned due to its inductive effect.