Dihydropyrimidinones, such as monastrol and analogues, are heterocycles with known antineoplastic activity. Conformational analysis represents an important preliminary step in structure-activity correlation studies. Herein we describe the conformational analysis of monastrol and analogues by AM1 semi-empirical and ab initio HF/6-31G* calculations. Four equilibrium geometries were found (s-cis/ap, s-cis/sp, s-trans/ap and s-trans/sp), and the important internal rotations were those of the α,β-unsaturated carbonyl system and of the aryl group connected to the heterocycle.
conformational analysis; dihydropyrimidinones; Biginelli compound; AM1; HF/6-31G*
