Detalle de: ON THE TAUTOMERISM OF 2-PHENACYL-4-PYRIMIDINONES AND RELATED-COMPOUNDS

3‐Methyl‐2‐phenacyl‐4‐pyrimidinones 1 , 2 have been synthesized using the sulfide contraction. According to the NMR data, the compounds 1 , 2 exist exclusively as the benzoylmethylene tautomers a both in solution and in the solid state. AM1 calculations of the parent system are in agreement with the experimental observations. The study of the tautomeric equilibrium by this semiempirical method has been extended to other cases of enamino‐ketone/enolimine tautomerism.