ELECTROSTATIC POTENTIALS ON THE MOLECULAR-SURFACES OF CYCLIC UREIDES

Ab initio SCF-MO electrostatic potentials have been computed at the STO-5G/STO-3G level on the molecular surfaces of a group of cyclic ureides, in order to assess their relative reactivities toward nucleophiles, as in hydrolysis. The surfaces were defined by the 0.002 electron/bohr3 contour of the molecular electronic density. The relative hydrolytic stabilities within a series of NO2 and NF2 derivatives are predicted, on the basis of the magnitudes of the potentials above the acyl carbons. The surface electrostatic potentials of the polycarbonyl systems parabanic acid and alloxan are shown to be fully consistent with unusually short intermolecular distances that have been observed in crystallographic studies of these compounds.