Complete ¹H and ¹³C signal assignment of prenol‐10 with 3D NMR spectroscopy

Abstract

The complete assignment of (1)H and (13)C chemical shifts of natural abundance prenol-10 is reported for the first time. It was achieved using 3D NMR experiments, which were based on random sampling of the evolution time space followed by multidimensional Fourier transform. This approach makes it possible to acquire 3D NMR spectra in a reasonable time and preserves high resolution in indirectly detected dimensions. It is shown that the interpretation of 3D COSY-HMBC and 3D TOCSY-HSQC spectra is crucial in the structural analysis of prenol-10.

Solid-state NMR spectroscopy identifies three classes of lipids in Cryptococcus neoformans melanized cell walls and whole fungal cells

“…This observation suggested that the molecule contains two structurally similar carbons with overlapping resonances at 135 ppm but linkages to magnetically distinct repeating units. PPs fit this description, and their reported 13 C and 1 H chemical shifts (37)(38)(39)(40) are consistent with our data. The repeating isoprene units that comprise PPs can adopt either cis or trans configurations, yielding distinct chemical shifts for the C1 and C5 carbon signals of each stereoisomer.…”

“…Consequently, the 1 H-13 C pairs attributable to PPs are clearly visible because their cross-peaks are located in a relatively uncluttered spectral region. The protons covalently bonded to the C1 and C4 carbons of both cis and trans isomers were observed at ~2.0 ppm, and those bonded to the C5 carbons appeared at ~1.6 ppm (37,38). Additionally, the 1 H-13 C cross-peak at (5.10, 125) ppm corresponded to the C3 carbon and its bonded proton, whereas the C2 carbon was not observed in a HETCOR experiment because it has no attached protons.…”

Using indirect covariance processing for structure elucidation of small molecules in cases of spectral crowding

“…For comparison, 3D‐NOESY‐HSQC spectra49–54 were recorded. Few reports have been published on the use of 3D‐NMR on small molecules 55–61. This is partly due to the relative insensitivity and partly to the unfavorable ratio between experiment time and the most often unwanted wealth of information.…”

Study of near‐symmetric cyclodextrins by compressed sensing 2D NMR

“…Notably, only a few approaches have been successfully implemented in the area of nonlabelled organic compounds [36][37][38][39][40][41] because of the additional experimental limitations connected with low sensitivity and the sampling requirements. [31] The sensitivity problem can be partially solved mostly by the measurement at higher field.…”

“…Notably, only a few approaches have been successfully implemented in the area of nonlabelled organic compounds because of the additional experimental limitations connected with low sensitivity and the sampling requirements …”