Two-dimensional POMMIE carbon–proton chemical shift correlated 13C NMR spectrum editing

Abstract

Two pulse sequences are described for acquisition of two-dimensional, carbon–proton chemical shift correlated 13C NMR spectra by the "phase oscillations to maximize editing technique". One of these sequences provides two-dimensional, carbon–proton chemical shift correlated spectra in which the 1H–1H coupling constants are present in the 1H chemical shift dimension, whereas the other sequence includes a bilinear rotation decoupling unit that removes the vicinal 1H–1H couplings in this dimension. Extensions of these techniques to generation of two-dimensional, carbon–proton chemical shift correlated CH, CH2, and CH313C NMR subspectra from linear combinations of three two-dimensional data sets are described. Decreased residual signals in the edited 2D subspectra have been achieved by Pascal programs that include six floating point coefficients, and a method for their calibration is discussed. Results are reported for troleandomycin (1). Keywords: 13C nuclear magnetic resonance, carbon–proton chemical shift correlation, DEPT, Pascal programs, POMMIE, two-dimensional NMR spectrum editing, troleandomycin.