Determining the Configuration of Trans-4-Propyl-Cyclohexylcarboxylic Acid by NMR Method

Abstract

Trans-4-propyl-cyclohexylcarboxylic acid (Trans-4-PA) was synthesized. ¹H, ¹³C, and some 2D nuclear magnetic resonance (NMR) spectra were recorded and signals were assigned. Density functional theory (DFT) calculation was carried out to simulate the optimized trans- and cis-configuration of 4-PA. Both configurations were stable and in minimal energy states. The dihedral angles of H_α–C–C–H_β with respect to carboxylic carbon were measured in both of the two configurations. The Karplus equation was used to speculate on ³J value of H_α–H_β in both configurations. The experimental result was compatible with computed figures of trans-configuration. The Fourier transform infrared (FTIR) spectra were also measured and peaks were assigned.

Keywords:

• Configuration
• dihedral angles
• Karplus equation
• NMR spectroscopy
• trans-4-propyl-cyclohexylcarboxylic acid