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IR study of the proton acceptor ability of N‐ t ‐butoxycarbonylproline N′‐methylamide
Author(s) -
Parmentier J.,
De Wael K.,
Samyn C.,
ZeegersHuyskens Th.
Publication year - 1993
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360330415
Subject(s) - chemistry , intramolecular force , hydrogen bond , amide , ring (chemistry) , infrared spectroscopy , proton , acceptor , fourier transform infrared spectroscopy , hydrogen atom , medicinal chemistry , stereochemistry , crystallography , molecule , organic chemistry , physics , quantum mechanics , condensed matter physics , alkyl
Hydrogen bonding between N‐ t ‐butoxycarbonylproline N′‐methylamide and phenol derivatives (pK a = 10.20–7.75) are investigated by ir and Fourier transform ir spectrometry. The thermodynamic parameters determined in carbon tetrachloride solution show that the complexes are of medium strength, the stability constants at 298 K range from 80 to 1530 L mol −1 , and the enthalpies of complex formation range from – 30 to –34 kJ mol −1 . The study of the ir spectra in the ν OH , ν NH , and ν co regions shows that complex formation occurs at the oxygen atom of the amide carbonyl. Hydrogen‐bond formation at this site strengthens the intramolecular hydrogen bond of the seven‐membered ring. © 1993 John Wiley & Sons, Inc.