Homodecoupled 1,1- and 1,n-ADEQUATE: Pivotal NMR Experiments for the Structure Revision of Cryptospirolepine

Angew Chem Int Ed Engl. 2015 Aug 24;54(35):10160-4. doi: 10.1002/anie.201502540. Epub 2015 Jul 15.

Abstract

Cryptospirolepine is the most structurally complex alkaloid discovered and characterized thus far from any Cryptolepis specie. Characterization of several degradants of the original, sealed NMR sample a decade after the initial report called the validity of the originally proposed structure in question. We now report the development of improved, homodecoupled variants of the 1,1- and 1,n-ADEQUATE (HD-ADEQUATE) NMR experiments; utilization of these techniques was critical to successfully resolving long-standing structural questions associated with crytospirolepine.

Keywords: DFT calculations; HD-ADEQUATE; NMR spectroscopy; cryptolepis alkaloids; homodecoupling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaloids / chemistry*
  • Cryptolepis / chemistry*
  • Indole Alkaloids / chemistry
  • Magnetic Resonance Spectroscopy / methods*
  • Molecular Structure
  • Plant Extracts / chemistry*
  • Quinolines / chemistry

Substances

  • Alkaloids
  • Indole Alkaloids
  • Plant Extracts
  • Quinolines
  • cryptospirolepine