Intramolecular ester exchange of potent cytotoxic kulokekahilide-2

Masahiro Umehara, Yuuki Takada, Yoichi Nakao, Junji Kimura*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Kulokekahilide-2 is a 26-membered cyclic depsipeptide that exhibits potent cytotoxicity against HeLa and P388 cells with IC50 values of 3.2 and 16 ng/mL, respectively. We have achieved a total synthesis of natural kulokekahilide-2, the NMR spectra of which showed complex signals because of trans and cis conformers at the amide bond. Besides, the spectra revealed that a mixture of 26- and 24-membered cyclic depsipeptides had been produced due to intramolecular ester exchange. The isolated 24-membered compound was transformed into the 26-membered compound over a period of several days. The two isomers have been shown to be in equilibrium and to display almost the same cytotoxicity.

Original languageEnglish
Pages (from-to)840-843
Number of pages4
JournalTetrahedron Letters
Issue number7
Publication statusPublished - 2009 Feb 18


  • 24-membered cyclic depsipeptide
  • Cytotoxicity
  • Ester exchange
  • Kulokekahilide-2

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry


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