Premium
DPFGSE ‐ MDEC ‐ J ‐resolved COSY : An efficient method for selectively measuring proton–proton spin coupling constants of the multiplet signals
Author(s) -
Furihata Kazuo,
Tashiro Mitsuru
Publication year - 2018
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.4783
Subject(s) - multiplet , chemistry , coupling constant , vicinal , proton , pulse sequence , decoupling (probability) , two dimensional nuclear magnetic resonance spectroscopy , stereochemistry , analytical chemistry (journal) , nuclear magnetic resonance , spectral line , physics , organic chemistry , particle physics , quantum mechanics , astronomy , control engineering , engineering
Natural products such as polyketides often possess various spin systems, consisting of a methine group directly bonded to a methyl group (e.g., ─CH A ─CH B (CH 3 )─CH C ─). The methine proton H B splits into a broadened multiplet by coupling with several vicinal protons, rendering analysis difficult of n J H–H with respect to H B in double‐quantum filtered COSY or exclusive COSY. For the purpose of measuring n J H–H in the aforesaid spin system, we have developed new techniques, named multifrequency homo‐decoupling (MDEC)‐ J ‐resolved COSY and DPFGSE‐MDEC‐ J ‐resolved COSY. This method incorporates MDEC pulse scheme into J ‐resolved COSY for the selective decouple of individual methyl groups, avoiding decoupling of the target protons resonating in methyl region. Determinations of n J H–H of the multiplet signals can easily be performed using the proposed pulse sequence.