Abstract: | The synthesis of the previously unreported 1-nitrophenoxathiin is described. The 13C-nmr spectrum of the title compound is assigned based on chemical shift additivities and 1H-13C spin-coupling constants. From the observed 13C-nmr chemical shift of the alpha-carbon the title compound was predicted to have a molecular dihedral angle, Ø = 143.3°, based on a recently described interrelation between the alpha-carbon 13C-nmr chemical shift and the dihedral angle. Independent measurement of the dihedral angle in a crystallographic study has shown that there are two independent molecules contained in the assymetric unit which posess dihedral angles, Ø = 145.7 and 163.4°, the former in excellent agreement with the angle predicted by the assigned 13C-nmr data. |