Premium
Carbon‐13 nuclear magnetic resonance studies of leonurine hydrochloride and its analogues
Author(s) -
Langford Gordon E.,
Yates Peter,
Yeung Hin Wing,
Cheng Kin Fai
Publication year - 1980
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270140610
Subject(s) - methylene , chemical shift , chemistry , substituent , aqueous solution , hydrochloride , side chain , carbon fibers , methylene blue , stereochemistry , organic chemistry , materials science , catalysis , photocatalysis , composite number , composite material , polymer
The 13 C NMR spectra of leonurine hydrochloride and thirteen of its analogues in DMSO‐ d 6 have been analyzed. Changes in the aromatic substituents have no significant effect on the chemical shifts of the side chain methylene carbons indicating that they do not influence the conformation of the latter. Observed deviations from additivity of substituent effects for the methylene carbon chemical shifts suggest that the methylene side chains of these compounds may be more tightly coiled than are the corresponding n ‐alkanes. In representative cases no change in conformation is evident in 50% aqueous DMSO‐ d 6 solutions, indicating that similar considerations may apply in aqueous media.