19F-NMR Diastereotopic Signals in Two N-CHF₂ Derivatives of (4S,7R)-7,8,8-Trimethyl-4,5,6,7-tetrahydro-4,7-methano-2H-indazole

Molecules. 2017 Nov 17;22(11):2003. doi: 10.3390/molecules22112003.

Abstract

In this paper, we report the anisochrony of the fluorine atoms of a CHF₂ group when linked to a pyrazole ring. The pyrazole is part of (4S,7R)-7,8,8-trimethyl-4,5,6,7-tetrahydro-4,7-methano-2H-indazole also known as (4S,7R)-campho[2,3-c]pyrazole, which has two stereogenic centers. Gauge-Independent Atomic Orbital (GIAO)/Becke, 3-parameter, Lee-Yang-Parr (B3LYP)/6-311++G(d,f) calculated 19F chemical shifts of the minimum energy conformations satisfactorily agree with the experimental data. The energy differences between minima need to consider solvent effects (continuum model) to be satisfactorily reproduced.

Keywords: 19F‐NMR; B3LYP; GIAO; PCM; anisochrony; diastereotopic; indazoles; pyrazoles.

MeSH terms

  • Fluorine*
  • Indazoles / chemistry*
  • Magnetic Resonance Spectroscopy*
  • Models, Molecular
  • Molecular Conformation
  • Molecular Structure

Substances

  • Indazoles
  • Fluorine