For example, nucleoside analogs in which the furanose ring has been replaced by other heterocyclic rings such as isoxazoles, isoxazolines, or triazoles [4].
Due to the twisted conformation of the furanose rings, the dihedral angle between the H-2 and H-3 protons is usually 90[degrees] and, hence, in the spectra of compound 2, the coupling constant between H-2 and H-3 is 0 Hz.