Computer methods of structure elucidation by1H and13C NMR spectra using factographic databanks

Computer methods have been developed for structure elucidation by ¹ H and ¹³ C NMR spectra using factographic databanks containing spectral and structural data of many organic compounds (44,000 for ¹ H NMR and 27,000 for ¹³ C NMR). Information about the structure of compounds under study is obtained from the analysis of reference structures whose spectra are the best matches of the query spectra. This procedure identifies linked fragments composed of the nodes assigned to signals of the query spectrum when comparing it with reference spectra, and of inactive nodes separated from the former by one bond at most. Using many examples, it has been shown that this approach allows one to determine sufficiently large structural fragments of unknowns both by ¹ H and ¹³ C NMR spectra. The most reliable structures are obtained from the combined analysis of ¹ H and ¹³ C NMR spectral search results. Thus the relative occurrences of correct fragments among the n-first (n=1, 3, 5) fragments of the ranked list of candidates, output to the user, are 80, 93, and 96%, respectively.Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 3, pp. 51–60, May–June 1993.Translated by L. Smolina