Chemistry of withaferin-A: chemo, regio, and stereoselective synthesis of novel spiro-pyrrolizidino-oxindole adducts of withaferin-A via one-pot three-component [3+2] azomethine ylide cycloaddition and their cytotoxicity evaluation

Mol Divers. 2015 May;19(2):251-61. doi: 10.1007/s11030-015-9574-6. Epub 2015 Mar 8.

Abstract

Withaferin-A (WA) has attracted the attention of chemists as well as biologists due to its interesting structure and various bio-activities. In light of the promising biological importance of WA as well as pyrrolidine-2-spiro-3'-oxindole ring system, we became interested in the synthesis of a combined motif involving both the ring systems via the 1,3-dipolar cycloaddition of WA at Δ(2)-bond of the α,β-unsaturated carbonyl system. We now report a facile, atom-economic synthesis of novel spiro-pyrrolizidino-oxindole adducts of withaferin-A (10 compounds) via the intermolecular cycloaddition of azomethine ylides generated in situ from proline and isatins/acenaphthoquinone. The reaction is highly chemo, regio, and stereoselective affording the cis-fused products with β-orienting hydrogen. The structures were determined by 1D/2D NMR spectroscopic data analysis and unequivocally confirmed by X-ray crystallographic analysis in some cases. Bioevaluation of the compounds against six cancer lines (e.g., CHO, HepG2, HeLa, HEK 293, MDCK-II, and Caco-2) identified 4 promising potential anticancer compounds.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cell Survival / drug effects
  • Cycloaddition Reaction
  • Humans
  • Indoles
  • Molecular Conformation
  • Molecular Structure
  • Oxindoles
  • Spiro Compounds
  • Stereoisomerism
  • Withanolides / chemical synthesis
  • Withanolides / chemistry*
  • Withanolides / toxicity

Substances

  • Indoles
  • Oxindoles
  • Spiro Compounds
  • Withanolides
  • 2-oxindole
  • withaferin A