Accordion-optimized direct chemical shift correlations

A pulse sequences is described for the accordion optimization of direct het eronuclear correlation experiments using single quantum coherence. The ADSQ C (accordion-optimized direct correlation single quantum coherence) experim ent detects a wide range of one-bond coupling constants using accordion opt imization. A sample of the antibiotic ceftiofur was employed because of the large range of one-bond coupling constants associated with the various str uctural components, spanning from 130 Hz (aliphatic) to 210 Hz (furan). The accordion-optimized experiment afforded, on average, similar signal-to-noi se ratios for most of the direct correlations as compared with the traditio nal gHSQC experiment. However, the resonances with the larger (1)J(C-13,H-1 ) couplings exhibited significant enhancements, particularly the furanyl re sponse with a coupling of 210 Hz. Copyright (C) 2001 John Wiley & Sons, Ltd .