Evaluation of a (1)h-(13)c NMR spectral library.

A simple database of (13)C/(1)H-(13)C spectral lists for 11 673 natural products was created in standard commercial database format. Over 50% of the spectra were predicted using HOSE code descriptors derived from the 50% of spectra having experimental values. Prediction errors obtained by prediction of and comparison to the experimental spectra revealed an exponentially decaying dependence between the average absolute error and the depth of the matching HOSE codes. A subset of the library containing over 1000 (1)H-(13)C assigned experimental spectral lists were used to test against eight alternate query data sets. These sets represent query data from various combinations of 1D-(13)C, 1D-DEPT, and 2D-(1)H-(13)C spectra. Simulated query lists were generated using Monte Carlo methods. As expected, queries based on 2D-(1)H-(13)C data were more likely to find the correct match under unfavorable conditions.