z-logo
Premium
Substituent Effects on Phosphate‐Catalyzed Proton Exchange in Amides
Author(s) -
Wang WeiHsien,
Cheng ChingChih,
Lee MingChao,
Huang ChiungYi
Publication year - 1991
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.199100059
Subject(s) - chemistry , substituent , catalysis , phosphate , proton , medicinal chemistry , kinetics , concerted reaction , organic chemistry , computational chemistry , stereochemistry , physics , quantum mechanics
The kinetics of phosphate‐catalyzed proton exchange have been measured with NMR lineshape analysis for a series of amides, ureas, and carbamates. A hypothetical energy profile for transition structures of concerted phosphate catalysis ‡ c and of stepwise phosphate catalysis ‡ 1 , ‡ 2 is used for discussion of the substituent effects. The concerted mechanism of phosphate catalysis operates only for amides RCONHCH 3 for which the electron‐donating ability of the substituent R is comparable with, or better than, that of the methyl group. We conclude that concerted phosphate catalysis is inoperative in proteins or polypeptides.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here