Correlations of the physicochemical parameters of azaindoles with their reactions

Abstract

Using the AM1 semiempirical quantum method the enthalpies of formation, ionization energies, electron affinities, energy differences between highest occupied and lowest unoccupied orbitals, atomic charges, bond orders, and dipole moments have been calculated for 4-, 5-, 6-, and 7-azaindoles. A correlation has been built up between the calculated physicochemical parameters and the Hammett para-substituent and inductive constants. The 1H to 7H proton transfer in 7-azaindole has been quantitatively described.

Palladium-Catalyzed Synthesis of 2,3-Disubstituted 5-Azaindoles via Heteroannulation Reaction and of 2-Substituted 5-Azaindoles through Domino Sila-Sonogashira/5-Endo Cyclization

“…Therefore, applying methods of indole synthesis to prepare azaindoles and particularly 5-azaindoles is not trivial. − Theoretical studies have been realized to explain the particular properties of azaindoles . It seems that the electron-deficient nature of the pyridine ring and, in the case of 5-azaindoles, the para relationship between the two nitrogen atoms are responsible of their uncommon behavior.…”

“…13−15 Theoretical studies have been realized to explain the particular properties of azaindoles. 16 It seems that the electron-deficient nature of the pyridine ring and, in the case of 5-azaindoles, the para relationship between the two nitrogen atoms are responsible of their uncommon behavior. On the other hand, 5-azaindoles possess interesting biological properties and can be found as key skeletons of anthelmintic agents, 17 thrombin inhibitors, 18 coagulation factors inhibitors, 19,20 kinase inhibitors, 21−23 5-HT 6 receptor ligands, 24 HIV-1 inhibitors, 25 and CB 2 agonists.…”