2D 1H-15N HMBC NMR acquired at natural abundanceand DMSO titration monitored by 1D 1H NMR verified the existenceof an intramolecular hydrogen bond that was designed to mimic thepyrimidinone ring of a class of kinase inhibitors. A scalar couplingacross the hydrogen bond was detected in organic and aqueous solvent,suggesting a simple and general approach for testing the propensity ofintramolecular hydrogen bonds to stabilize pseudo-rings in drugscaffolds.