Ab initio Hartree-Fock investigation of 1-H-pyrrolo[3,2-b]pyridine-3-yl acetic acid

The potential energy surface of 1-H-pyrrolo3,2-b]pyridine-3-yl acetic acid has been investigated via RIIF/6-31G* calculations. The stationary points and reaction paths for syn orientation of the COOH group were determined and are compared with those of the derivatives of 3-indole acetic acid, which act as plant growth hormones. 1-H-pyrrolo3,2-b]pyridine-3-yl acetic acid forms a kinetically stable conformer with a strong intramolecular hydrogen bond, in which the COOH group is in anti orientation. The influence of this hydrogen bond on bond lengths and vibration frequencies is described.