Abstract
Derivatives of a heterocyclic system 3-(pyrrol-1-yl)thieno[2,3-b]pyridine 5 and 6 carrying various substituents in the position 2 were synthesized. Some of these products were used to build up a variety of nitrogen- and/or oxygen-containing heterocyclic rings in that position. The electronic configurations of selected products were investigated using the AM1 semi-emperical molecular orbital method. Considerable variations in the magnitude and oriention of the dipole moment were observed. Further, the relative stability of the structures was investigated at physiological conditions via calculation of the electrostatic component of the solvation free energy. The synthesized series showed favourable solvation free energies which were within the range from -30 to -23 kcal/mol. The high polarity and favourable solvation free energy changes at physiological conditions suggest that substitution in-the position 2 could enhance the biological activity of the 3-(pyrrol-1-yl)thieno[2,3-b]pyridine derivatives.