NMR study of 5-substituted pyrazolo[3,4-c]pyridine derivatives.
Substituted pyrazolopyridines are potent inhibitors of phosphodiesterases and cyclin-dependent kinases. In this study, NMR was used to investigate the potential N1-H and N2-H tautomerism of 5-substituted pyrazolo[3,4-c]pyridine derivatives. Six compounds were fully characterized by using (1)H, (13)C, and (15)N chemical shifts and indirect (1)H--(13)C and (1)H--(15)N coupling constants. The (1)H NMR spectra were measured over a broad range of temperatures. All of the compounds were shown to exist predominantly in the N1-H tautomeric form. Complementary quantum-chemical calculations of the chemical shieldings and indirect spin-spin couplings support the structural conclusions drawn.
Tsikouris
Orestis
O
Department of Pharmacy, Division of Pharmaceutical Chemistry, University of Athens, Panepistimiopolis Zografou, Athens GR-15771, Greece.
Bartl
Tomás
T
Tousek
Jaromír
J
Lougiakis
Nikolaos
N
Tite
Tony
T
Marakos
Panagiotis
P
Pouli
Nicole
N
Mikros
Emmanuel
E
Marek
Radek
R
D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011720:Pyrazoles / Q000138:chemical synthesis / Q000737:chemistry*; D011725:Pyridines / Q000138:chemical synthesis / Q000737:chemistry*; D011789:Quantum Theory; D013237:Stereoisomerism
D011720:Pyrazoles; D011725:Pyridines