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15 N nuclear magnetic resonance spectroscopy. Natural abundance 15 N NMR of monosubstituted indoles
Author(s) -
Rosenberg E.,
Williamson Kenneth L.,
Roberts John D.
Publication year - 1976
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.1270080302
Subject(s) - substituent , chemical shift , chemistry , indole test , ring (chemistry) , nuclear magnetic resonance spectroscopy , abundance (ecology) , resonance (particle physics) , nitrogen , spectroscopy , carbon 13 nmr , spectral line , carbon 13 , nuclear magnetic resonance , stereochemistry , organic chemistry , physics , atomic physics , quantum mechanics , astronomy , fishery , biology
15 N chemical shifts of twenty‐four substituted indoles have been determined in natural abundance (in organic solvents) using Fourier transform NMR. The overall chemical shift range is 27 ppm, with groups in the 2‐, 3‐ and 5‐ring positions showing the largest substituent effects. Substituents capable of resonance interaction with the indole nitrogen give shifts in the expected directions but they cannot be correlated with known substituent parameters. Compounds measured in DMSO give 0·2 to 10·2 ppm downfield shifts with respect to the same compound measured in CDCl 3 . 13 C NMR data for previously unreported compounds are also reported.