A computer search system for similar organic compounds in carbon-13 nuclear magnetic resonance data files

From the ¹³C-NMR spectrum of an unknown compound, the system provides a list of compounds ranked according to their similarity to the unknown. The similarity is estimated in a three-dimensional feature space, rather than by direct match of all peaks. All the spectra in the library are first converted to pattern points in the feature space by a dimensionality-reduction method. Thus, the search for similar compounds is simplified to a search for points within a given distance from the point representing the unknown. The compounds listed can be offered as the result or used for further operations (match of carbon number and peak position) in order to get a more exact result. An auto-optimization option is included to provide efficiency and user convenience.