The structure of benzoyldimedone was established by X-ray diffraction analy
sis. The only tautomer was found. In this tautomer, the enol proton is cova
lently bound to the oxygen atom that is remote from the phenyl group. The r
ole of steric and electronic factors in stabilization of the enol structure
is analyzed. The geometric characteristics of the ring formed through an i
ntramolecular hydrogen bond are discussed.