Observation of untoward ³ J_cc correlations in 1,1-ADEQUATE spectra of pyrimidine analogs: Avoiding potential interpretation pitfalls

Recently, it has been reported that large ⁿ J_CC correlations can sometimes be observed in 1,1-ADEQUATE spectra with significant intensity, which opens the possibility of structural misassignment. In this work, we have focused on pyrimidine-based compounds, which exhibit multiple bond correlations in the 1,1-ADEQUATE experiment as a consequence of ³ J_CC coupling constants greater than 10 Hz. Results are supported by both the experimental measurement of ³ J_CC coupling constants in question using J-modulated-ADEQUATE and density functional theory calculations.