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Discrimination of two methylene groups in non‐symmetric succinate esters in sesquiterpene dimers by heteronuclear 13 C{ 1 H}NOE spectroscopy
Author(s) -
Fukushi Eri,
Kawabata Jun,
Mizutani Junya
Publication year - 1995
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.1260331113
Subject(s) - chemistry , methylene , heteronuclear molecule , chemical shift , stereochemistry , spectroscopy , nuclear magnetic resonance spectroscopy , crystallography , double bond , analytical chemistry (journal) , medicinal chemistry , organic chemistry , physics , quantum mechanics
In the assignment of the non‐equivalent methylene group of an asymmetric succinate residue in the macrocyclic lactone ring of shizukaols B and F, isolated from Chloranthus japonicus , distinction of two‐bond C—H and three‐bond C—H was needed. The steady state and transient 13 C{ 1 H}NOE was used to detect two‐bond C‐H. One pair of non‐equivalent methylene protons was saturated simultaneously by quasi‐simultaneous irradiation. Inversion of two protons whose chemical shifts were close was carried out by a squared pulse, and inversion of two protons whose chemical shifts were far from each other was performed using a double DANTE pulse train.