Nuclear Magnetic Resonance Spectroscopy. Abnormal Splitting of Ethyl Groups due to Molecular Asymmetry. II.

Diethyl sulfite,2-5 acetaldehyde diethyl acetal, and cyclopropylcarbinyl ethyl ether offer striking examples of the magnetic non-equivalence of the methylene hydrogens in compounds of the type R-CH_2-O-XR_1R_2R_3 (with R = CH_3 and X = S, C, P, etc.). Thus, the nuclear magnetic resonance (n.m.r.) spectra of such methylene protons are often typical of AB rather than A_2 systems.