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Chlorine substituent effects for indole and tryptophan in 13 C NMR
Author(s) -
Lee Minsu,
Phillips Robert S.
Publication year - 1994
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570310403
Subject(s) - chemistry , conformational isomerism , indole test , substituent , chemical shift , carbon 13 nmr , ring (chemistry) , methanol , chlorine , coupling constant , stereochemistry , population , nmr spectra database , computational chemistry , spectral line , molecule , organic chemistry , physics , particle physics , astronomy , demography , sociology
Abstract The 13 C and 1 H nmr spectra of chloroindoles and chlorotryptophans in methanol‐ d 4 were assigned based on 1‐D and 2‐D nmr techniques, including COSY, inverse‐detected direct (HMQC) and long‐range (HMBC) correlation. Chlorine substitutent effects in chemical shifts (SCS) for chlorotryptophans and chloroindoles were calculated and compared. The correlations were linear except for 4‐chlorotryptophan, which suggests structural changes on the indole ring between 4‐chlorotryptophan and 4 chloroindole. The conformational analysis based on the coupling constants of the side chain also showed a change in the fractional population of the rotamers between 4‐chlorotryptophan and the other chlorotryptophans.