Folded conformations due to arene interactions in dissymmetric and symmetric butylidene-linker models based on pyrazolo[3,4-d]pyrimidine, purine and 7-deazapurine

Acta Crystallogr C Struct Chem. 2014 Jun;70(Pt 6):555-61. doi: 10.1107/S2053229614009449. Epub 2014 May 9.

Abstract

The butylidene-linker models 1-[2-(2,6-dimethylsulfanyl-9H-purin-9-yl)-2-methylidenepropyl]-4,6-bis(methylsulfanyl)-1H-pyrazolo[3,4-d]pyrimidine, C18H20N8S4, (XI), 7,7'-(2-methylidenepropane-1,3-diyl)bis[3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one], C20H22N6O2S2, (XIV), and 7-[2-(4,6-dimethylsulfanyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)-2-methylidenepropyl]-3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one, C19H21N7OS3, (XV), show folded conformations in solution, as shown by (1)H NMR analysis. This folding carries over to the crystalline state. Intramolecular π-π interactions are observed in all three compounds, but only (XIV) shows additional intramolecular C-H···π interactions in the solid state. As far as can be established, this is the first report incorporating the pyrrolo[2,3-d]pyrimidine nucleus for such a study. In addition to the π-π interactions, the crystal structures are also stabilized by other weak intermolecular C-H···S/N/O and/or S···N/S interactions.

Keywords: 7-deazapurine; arene interactions; butylidene linker; crystal structure; folded conformations; purine; pyrazolo[3,4-d]pyrimidine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallography, X-Ray
  • Hydrogen Bonding
  • Magnetic Resonance Spectroscopy
  • Molecular Conformation
  • Purines / chemistry*
  • Pyrazoles / chemistry*
  • Pyrimidines / chemistry*
  • Pyrroles / chemistry*

Substances

  • 1-(2-(2,6-dimethylsulfanyl-9H-purin-9-yl)-2-methylidenepropyl)-4,6-bis(methylsulfanyl)-1H-pyrazolo(3,4-d)pyrimidine
  • 7,7'-(2-methylidenepropane-1,3-diyl)bis(3-methyl-2-methylsulfanyl-3H-pyrrolo(2,3-d)pyrimidin-4(7H)-one)
  • 7-deazapurine
  • Purines
  • Pyrazoles
  • Pyrimidines
  • Pyrroles
  • pyrazolo(3,4-d)pyrimidine
  • pyrimidine
  • purine