IR study of the proton acceptor ability of N-t-butoxycarbonylproline N′-methylamide

✍ Scribed by J. Parmentier; K. De Wael; C. Samyn; Th. Zeegers-Huyskens

• Publisher: Wiley (John Wiley & Sons)
• Year: 1993
• Tongue: English
• Weight: 439 KB
• Volume: 33
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360330415

✦ Synopsis

Abstract

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~co~ 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.