Related Experiment Video
Updated: Aug 3, 2026

On-line Analysis of Nitrogen Containing Compounds in Complex Hydrocarbon Matrixes
Published on: August 5, 2016
NMR and molecular mechanics study of pyrethrins I and II
J K Rugutt1, C W Henry, S G Franzblau
1Department of Chemistry, Louisiana State University, Baton Rouge 70803, USA.
Abstract:
Bioassay-directed fractionation of the organic extract of the Kenyan pyrethrum flowers (Chrysanthemum cinerariaefolium Vissiani) resulted in the isolation of two natural pyrethrin esters, pyrethrin I (PI) and pyrethrin II (PII) as the major constituents. These esters elicited inhibition of the multiple drug resistant (MDR) Mycobacterium tuberculosis. The high-field (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of PI and PII were unequivocally assigned using modern two-dimensional (2D) proton-detected heteronuclear multiple-quantum coherence (HMQC) and heteronuclear multiple-bond correlation (HMBC) experiments. The conformations of both esters were deduced from (1)H-(1)H vicinal coupling constants and confirmed by 2D nuclear Overhauser effect spectroscopy (NOESY). Computer molecular modeling (MM) studies revealed that PI and PII molecules adopt a "love-seat" conformation in chloroform (CDCl(3)) solution.
Related Concept Videos
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
Basicity of Heterocyclic Aromatic Amines
NMR Spectroscopy of Aromatic Compounds
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
NMR Spectroscopy Of Amines

