Cyclopenta[cd] pyrene and monomethyl isomers

Palladium-catalyzed and alcohol-enabled transformation to synthesize benzocyclic ketones

Catalytic carbonyl formation ranks as one of the most important synthetic methodologies. Herein, a highly effective palladium-catalyzed and alcohol-promoted transformation of nitriles to synthesize benzocyclic ketones is described. It provides a straightforward access to potentially valuable indanone compounds in high yields in the presence of alcohol. It avoided the usage of carbon monoxide or an additional hydrolysis procedure.

Theoretical Calculation of Hydrogen-Bonding Strength for Drug Molecules

Hydrogen bond is an important type of interaction between drug molecules and their receptors. We present here a computational method for accurately predicting the hydrogen-bonding strength for different acceptors with respect to a given donor or vice versa. The method is based on quantum chemistry DFT calculation of the interaction energy between hydrogen bond donors and acceptors. An excellent linear correlation is observed between the calculated hydrogen-bonding energies and the experimentally measured hydrogen-bonding constants log Kβ on a variety of known hydrogen bond acceptors and donors. These results not only indicate the predictive power of this method but also shed light on factors that determine the magnitude of experimentally measured hydrogen-bonding constants for different acceptors with respect to a given donor, suggesting a primarily enthalpic contribution from hydrogen-bonding energy. The method can be used for evaluating the effects of steric interference and inhibitor binding geometry on hydrogen-bonding strength in drug design.

Theoretical Prediction of the Abraham Hydrogen Bond Acidity and Basicity Factors from a Reaction Field Method

A new methodology for the theoretical evaluation of the hydrogen bond acidity SigmaalphaH2 and basicity SigmabetaH2 Abraham descriptors is presented. The first step is a quantum mechanical calculation at the Hartree-Fock level using a moderate basis set, including the solute-solvent interaction through a Reaction Field method, namely the Polarizable Continuum Model (PCM). The density charge on the surface of the cavity surrounding the solute, which contains the signature of the specificity of the molecule, is then translated into effective atomic charges through a suitable algorithm. These atomic charges can be related to the acidity and basicity properties of the molecule by a proper parametrization of empirical atomic factors, which account for the specific H-bonding capabilities of the individual atoms and group of atoms. The Abraham descriptors can be then evaluated with a high degree of accuracy for a large number of classes of molecules. Calculations performed for a set of 55 compounds give a standard deviation of 0.029 and 0.044 for SigmaalphaH2 and SigmabetaH2, respectively. The correlation coefficients are 0.994 and 0.974.

Carbopalladation of nitriles: synthesis of benzocyclic ketones and cyclopentenones via Pd-catalyzed cyclization of omega-(2-iodoaryl)alkanenitriles and related compounds

An efficient procedure for the synthesis of 2,2-disubstituted benzocyclic ketones by intramolecular carbopalladation of nitriles has been developed. The cyclization of substituted 3-(2-iodoaryl)propanenitriles affords indanones in high yields. The reaction is compatible with a wide variety of functional groups. This methodology has been extended to the synthesis of tetralones and cyclopentenones.