Two stereoisomeric pentacyclic oxindole alkaloids from Uncaria tomentosa: uncarine C and uncarine E

Acta Crystallogr C. 2001 Apr;57(Pt 4):480-2. doi: 10.1107/s0108270101000932.


The chloroform solvate of uncarine C (pteropodine), (1'S,3R,4'aS,5'aS,10'aS)-1,2,5',5'a,7',8',10',10'a-octahydro-1'-methyl-2-oxospiro[3H-indole-3,6'(4'aH)-[1H]pyrano[3,4-f]indolizine]-4'-carboxylic acid methyl ester, C(21)H(24)N(2)O(4).CHCl(3), has an absolute configuration with the spiro C atom in the R configuration. Its epimer at the spiro C atom, uncarine E (isopteropodine), (1'S,3S,4'aS,5'aS,10'aS)-1,2,5',5'a,7',8',10',10'a-octahydro-1'-methyl-2-oxospiro[3H-indole-3,6'(4'aH)-[1H]pyrano[3,4-f]indolizine]-4'-carboxylic acid methyl ester, C(21)H(24)N(2)O(4), has Z' = 3, with no solvent. Both form intermolecular hydrogen bonds involving only the oxindole, with N.O distances in the range 2.759 (4)-2.894 (5) A.

MeSH terms

  • Alkaloids / chemistry*
  • Crystallography, X-Ray
  • Indoles / chemistry*
  • Models, Molecular
  • Molecular Structure
  • Oxindoles
  • Plants, Medicinal / chemistry*
  • Spiro Compounds / chemistry*
  • Stereoisomerism


  • Alkaloids
  • Indoles
  • Oxindoles
  • Spiro Compounds
  • uncarine E
  • uncarine C