N.M.R. spectra of molecules containing quadrupolar nuclei

Abstract
It is shown that the relative signs of J AX and J BX for a 2A 2B 3X spin system (where X is undergoing rapid relaxation) can always be measured by studying the double-quantum transition in the AB region. The method is applied to the case of 2-bromothiazole; the two proton-nitrogen scalar coupling constants are shown to have the same sign.