Abstract

COMPUTATIONAL STUDY ON THE PROTONATION OF PHENOXYMETHYLPENICILLIN- ENOL BY AM1 METHOD

Pingili Kavitha Reddy and *Bojja Rajeshwar Rao

ABSTRACT

The geometry, conformation and electronic structure of keto-enol tautomerism in phenoxymethylpenicillin have been optimized and calculated in the gas phase, usually considering an isolated molecule surrounded by vacuum, using semi-empirical molecular orbital AM1 method. In this connection, the mechanism of protonation on phenoxymethylpenicillin-enol has been studied with the different positions of net charges at nitrogen atoms in the molecule. Further, the heats of formation (ΔHfo), dipole moment (μ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (EHOMO and ELUMO) have been performed and discussed. The conformational analyses of mono- and di-protonated phenoxymethylpenicillin-enol and their stable conformations have also been evaluated.

Keywords: AM1, Phenoxymethylpenicillin, keto-enol tautomerism, induction effect, frontier molecular orbital.