Review  scientific supervisor for the master's thesis MARCHENKO Sergei Alekseevich on " Conformation analysis of triterpenoids and their derivatives by NMR spectroscopy”, performed at the department of physical organic chemistry of the institute of chemistry of St. Petersburg state University during the training period from September 2016 to June 2018 on the educational program “Chemistry”.   The master's work of Marchenko S. A. is devoted to the search for a reliable system of evidence of the structure and spatial structure of triterpenoids and their derivatives on the basis of NMR spectroscopy. As a result of the analysis of literary data and preliminary studies synthesized at the department of chemistry of natural compounds (Zorina A. D et al). 5 compounds belonging to the dammarane and oleanane type were selected, in the study of which the approbation of the approach based on the use of quantitative data of 1H NMR spectroscopy – vicinal constants 3JH-H and nuclear Overhauser effects of ηH-H was carried out, and their comparison with the corresponding calculated data. In addition to the practical problem of conformational analysis of the selected triterpenoids, much attention was paid to the assessment of the possibilities and limitations of the use of various homo - and heteronuclear correlation methods of NMR spectroscopy, as well as the quantitative determination of the spectral and relaxation characteristics of the objects of study at a frequency of 300 MHz. This is the relevance, novelty and practical significance of this work. The results obtained are in the form of a set of general recommendations for the use of NMR methods and specific solutions for the quantitative measurement of the characteristics most important for the conformational analysis (3JH-H, ηH-H), as well as in the form of a description of procedures for taking into account the effect of anisotropy of diffusion on the accuracy of estimates of interproton distances in triterpenoids, including an experimental determination of the anisotropy of diffusion D║/D┴ by comparing the heteronuclear effects of Overhauser 1H→13C in the methylene group, the parameters of the multi-pulse NMR methods used can be correctly optimized and are an example of the maximum individualization of the general approach of using 1H NMR  spectroscopy in the conformational analysis of chemical compounds, taking into account the features of their spectral and relaxation NMR characteristics. No less important result of this work is the obvious possibility of extending the approach to other groups of triterpenoid and close to them polycyclic isoprenoid compounds. Consequently, the prospects for further development of this topic are very optimistic. In the process, Marchenko S. A. has established itself as a responsible and quite independent specialist with the necessary theoretical knowledge in the field of structural organic chemistry and the practical use of NMR spectroscopy in structural and conformational analysis of natural compounds, as well as practical skills of computer processing of spectral information, resulting from the use of various homo- and heteronuclear correlation NMR methods, and the critical analysis. He was actively involved in the preparation of the article, which was published in 2017, and in April 2018 he presented this work at the 15th international school-conference on magnetic resonance. The ability to defend his own point of view on the interpretation of the data, peace of mind and self-control in difficult situations, which Marchenko S. A. has repeatedly shown in the process of training and research, should help him to successfully defend his master's thesis with an assessment of “excellent”.  Associate Professor, Doctor of Chemistry                                                             / Selivanov S. I./