PM3 CONFORMATIONAL ANALYSIS OF THE (3S,5R,6R)-6 ACETYLAMIDOPENICILLANIC ACID. II. ELECTRONIC PROPERTIES

A conformational analysis with the semiempirical PM3 method was performed for the (3S,5R,6R)-6-acetylamidopenicillanic acid. 47 distinct conformers were found within 11.36 kcal/mol. Dependence of some electronic properties of these conformers (HOMO and LUMO energies, dipole moment, v(min) in frequence of the minimum vibration, v(MAX) frequence of the maximum vibration, zero point vibration energy (ZPVE) and charge densities on atoms S1, N4, N14, O8, O12, O13 and O17) with respect to some geometrical characteristics (pseudochirality of the N14 atom, the syn-anti arrangement of the O17 and H28 atoms of the amidic group and the three puckering classes of the thyazolidinic ring (noted with a, b, c)) is discussed.