BENZOTRIAZOLE DERIVATIVES OF DIPHENYLAMINE ARE NEW UV RADIATION ABSORBERS

In order to develop UV absorbers with improved extinction coefficients, previously obtained UV absorbers 1-(2-aminophenyl)-1H- and 2-(2-aminophenyl)-2H-benzotriazoles functionalization was carried out through aromatic nucleophilic substitution reaction with nitrohalogenarenes and followed reduction of the obtained nitrodiphenylamines. The conditions for these reactions were selected to synthesize target products with high yield. As a result, 10 new diphenylamine derivatives containing 1H- or 2H-benzotriazole cycles were synthesized. The structures of the obtained multifunctional compounds were determined using 1H, 13C NMR spectroscopy and high-resolution mass spectrometry. The assignment of proton signals is based on data from 2D 1H-1H NOESY spectra. The electronic absorption spectra of synthesized 2-nitro- and 2-aminodiphenylamines in the scanning range of 200-700 nm, were recorded. All the obtained diphenylamines absorbed UV radiation in the medium wavelength range much more efficiently than the initial 1-(2-aminophenyl)-1H- and 2-(2-aminophenyl)-2H-benzotriazoles. The ability to absorb medium-wavelength UV radiation depended both on the combination of various substituents in the compound and on the structure of benzotriazole. Among the studied diphenylamines, the highest value of the molar extinction coefficient in the range of 280-315 nm was 2-substituted diphenylamines containing the 2H-benzotriazole cycle. At the same time, such 2-nitrodiphenylamines were more effective than the corresponding 2-nitro derivatives. In contrast to the initial benzotriazole derivatives of primary amines, almost all diphenylamines had absorption maxima in the long-wavelength region of the UV spectrum. At the same time, a number of diphenylamines based on 2-(2-aminoaryl)-2H-benzotriazole are less effective UV-A absorbers. Varying the nature of the substituents, for example, replacing the nitro group with amino and trifluoromethyl with ethoxycarbonyl, made it possible to increase the molar extinction coefficient of the substance in the long-wavelength region of the spectrum. For citation: Begunov R.S., Khlopotinin A.I. Benzotriazole derivatives of diphenylamine are new UV radiation absorbers. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 5. P. 112-120. DOI: 10.6060/ivkkt.20256805.7200.