Quantum chemical study of 2-substituted 4-oxo-and 4-thioxospiro(benzo[h]quinazoline-5,1′-cycloalkanes) in alkylation reactions

Abstract

The steric and electronic structures of 2-substituted 4-oxo- and 4-thioxospiro(benzo[h]quinazoline-5,1′-cycloalkanes and their deprotonated forms have been calculated by the semiempirical PM-3 quantum chemical method. Using the conclusions of limiting orbital theory, a quantum chemical explanation has been derived, based on the calculations made, for the selectivity of alkylation of the systems investigated.