In:
Justus Liebigs Annalen der Chemie, Wiley, Vol. 1975, No. 7-8 ( 1975-09-24), p. 1379-1386
Abstract:
Model Experiments for Peptide Synthesis. — Kinetic Investigations of the Reactivity of Activated Carboxyl Functions Model experiments for peptide synthesis were carried out with N‐methylbenzylamine (2a) and N‐methyl‐N‐(trimethylsily1)benzylamine (2b) as nucleophiles and activated Z‐glycine derivates as electrophiles. 2‐Glycine was activated as the imidazolide l h as well as the ester of 4‐chlorophenol la , 4‐chlorothiophenol 1b , 4‐nitrophenol lf, 2,4,6‐trichlorophenol lc , 2,4,5‐trichlorophenol 1d , pentachlorophenol 1e and N‐hydroxysuccinimide 1g . The kinetic investigations were carried out by 1H‐NMR spectroscopy in chloroform at 28°C. The Z‐glycine ester of N‐hydroxysuccinimide and of 4‐chlorophenol show the greatest difference in reactivity; their rate constants differ by a factor of about 5000. — Only the reaction of 2‐glycine imidazolide with N‐methylbenzylamine shows exactly second order kinetics. The reasons for the deviation from this reaction order and a modified rate law are considered. The free energy of activation (AG:J for rotation of 2‐glycine‐N‐methylbenzylamide has been determined.
Type of Medium:
Online Resource
ISSN:
0075-4617
DOI:
10.1002/jlac.v1975:7/8
DOI:
10.1002/jlac.197519750715
Language:
English
Publisher:
Wiley
Publication Date:
1975
detail.hit.zdb_id:
1475010-7
SSG:
15,3
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