CC BY ND NC 4.0 · SynOpen 2017; 01(01): 0059-0062
DOI: 10.1055/s-0036-1588519
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Chain Length of Amphipathic-Type Thioesters Dramatically Affects Reactivity in Aqueous Amidation Reactions with Cysteine Esters

Ikumi Otomoa, Kanna Watanabea, Chiaki Kuroda*a, Kenichi Kobayashi*b
  • aDepartment of Chemistry, Rikkyo University, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan   Email: chkkuroda@rikkyo.ac.jp
  • bGraduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, Noshio, Kiyose, Tokyo 204-8588, Japan   Email: kenichik@my-pharm.ac.jp
This work was partly supported by the Strategic Research Foundation Grant-aided Projects for Private Universities from the Ministry of Education, Culture, Sports, Science, and Technology, Japan.
Further Information

Publication History

Received: 10 July 2017

Accepted after revision: 11 July 2017

Publication Date:
01 August 2017 (online)

Abstract

The reaction of five amphipathic-type thioesters, CH3(CH2) m COS(CH2) n COONa (m + n = 12), with cysteine hexyl, butyl, and ethyl esters were studied in aqueous medium. Compounds with the thioester group in close proximity to the carboxylate moiety (m = 10, n = 2) afforded amides in almost quantitative yield, whereas no reaction proceeded by using compounds with the thioester group distant from the carboxylate. In contrast, no clear difference in yield was observed among the five amphipathic-type thioesters upon reaction with valine hexyl ester. The results indicate that the reaction is affected by both the position of the thioester group and the hydrophilic/hydrophobic properties of the amino acid side chain.