The analysis of mixtures using the 2-D INADEQUATE NMR technique

The potential of the 2-D INADEQUATE NMR experiment for identifying different C-13/C-13 connectivities and distinguishing between signals of compounds with very similar structures is demonstrated for two mixtures: quinoline and 3-acetyl pyridine, and n-propanol and 1,2-propanediol, and for the isomeric forms of the two disaccharides: cellobiose and maltose. The 1-D C-13 NMR spectrum of the first mixture has features very similar to that of pyridine, whereas the second mixture shows absorptions characteristic of tetrahydrofuran, however the INADEQUATE experiment clearly distinguishes between pyridine and tetrahydrofuran and the two mixtures. For cellobiose and maltose, 22 and 23 separate signals have been assigned respectively to specific carbon nuclei of the alpha and beta anomers. (C) 1999 Elsevier Science B.V. All rights reserved.