Conformational analysis of natural products

Hetero- and homonuclear coupling constant calculation

Karplus-type equation for vicinal carbon-proton coupling constants for the C-S-C-H pathway in 1-thioglycosides

Tvaroska I, Mazeau K, Blanc-Muesser M, Lavaitte S, Driguez H, Taravel FR; Carbohydr Res 229 (1992) 225-231


The Karplus-type relationship for 3JCSCH values and glycosidic dihedral angles in 1-thioglycosides, based on 3JC,H values for a series of conformationally rigid derivatives, is in the form 3JC,H=4.44 cos2(phi)-1.06 cos (phi)+0.45, with J(O)=3.83, J(60)=1.03, and J(180)=5.95 Hz


Karplus curve

Coupling constant calculation

Karplus-type equations are frequently used to relate vicinal coupling constants, i. e. 3J, to torsion angles. To calculate a coupling constant for a given dihedral angle (θ) enter a value in the form and press Calculate.
To calculate a torsion angle from a coupling constant enter the coupling constant in the 3J field press Calculate. There may be up to four solutions.
The results are shown below!
Torsion angle (θ): °
Coupling constant (3J): Hz