Arbour CA, Kondasinghe TD, Saraha HY, Vorlicek TL, Stockdill JL. Epimerization-free access to C-terminal cysteine peptide acids, carboxamides, secondary amides, and esters
via complimentary strategies.
Chem Sci 2017;
9:350-355. [PMID:
29629104 PMCID:
PMC5868297 DOI:
10.1039/c7sc03553e]
[Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 11/07/2017] [Indexed: 01/03/2023] Open
Abstract
We present a convenient method for the diversification of peptides bearing cysteine at the C-terminus that proceeds to form a variety of carboxylic acid, carboxamide, 2° amide, and ester terminated peptides without any detectable epimerization of the α-stereocenter.
C-Terminal cysteine peptide acids are difficult to access without epimerization of the cysteine α-stereocenter. Diversification of the C-terminus after solid-phase peptide synthesis poses an even greater challenge because of the proclivity of the cysteine α-stereocenter to undergo deprotonation upon activation of the C-terminal carboxylic acid. We present herein two general strategies to access C-terminal cysteine peptide derivatives without detectable epimerization, diketopiperazine formation, or piperidinylalanine side products.
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