SHIFTING OF THE KETO ENOL EQUILIBRIUM IN 1,3-DIPHENYL-1,3-PROPANEDIONE BY METHYL SUBSTITUTION - AN AM1 STUDY

The stabilities of the tautomeric keto-enolic forms of the 1,3-diketo compounds dibenzoylmethane and methyldibenzoylmethane were studied by means of the semiempirical MO method AM1. An assessment of the stabili zing electronic and steric factors in both compounds was attempted. Th e dependence of the heats of formation on different rotamers for each compound allowed the energy minima to be found that were consistent wi th diffraction and NMR data.