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Updated: Jul 9, 2026
Enzymatic Synthesis of Epoxidized Metabolites of Docosahexaenoic, Eicosapentaenoic, and Arachidonic Acids
Published on: June 28, 2019
Investigating the stabilizing influences of organic sidechains in epoxides by rotational spectroscopy and
Dylan James1, Aaron Reynolds1, Jennifer van Wijngaarden1
1Department of Chemistry, York University, Toronto, Ontario, M3J 1P3, Canada. vanwijng@yorku.ca.
Abstract:
The conformer distributions of 1,2-epoxyhexane (C6H12O) and 1,2-epoxy-5-hexene (C6H10O) were characterized for the first time using Fourier transform microwave (FTMW) spectroscopy and quantum chemical calculations at the B3LYP-D3(BJ)/aug-cc-pVTZ level of theory. The latter identified 29 stable geometries for each molecule which differ by the arrangement of the three internal dihedral angles that define the orientation of the epoxide ring (α) and the butane or butene hydrocarbon sidechain (β, γ). Patterns of rotational transitions in the 6-20 GHz region were used to unambiguously identify the 14 lowest energy rotamers of 1,2-epoxyhexane and the 12 lowest energy rotamers of 1,2-epoxy-5-hexene which are within 5 kJ mol-1 and 2.7 kJ mol-1 of their respective global minima. Their relative energies are rationalized through natural bond orbital (NBO) analyses that identify potential attractive orbital interactions found for specific orientations of α, β and γ and through minor geometry changes observed in the organic sidechain that are consistent with steric effects.
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