A rapid and efficient method for the synthesis of novel dipyrazolo[3,4-b:3′,4′-d]pyridines (DPP) from pyrazolo[3,4-b]pyridine was successfully developed. The DPP derivative was further N-alkylated (6, 8) as well as N-linked with amino acids (13) and their photophysical properties were studied along with N-aryl DPP 4 and observed that the chromophores at C4 position in the aryl ring changed the absorption and emission λmax.
Keywords Pyrazolo[3,4-b]pyridine - Dipyrazolo[3,4-b:3′,4′-d]pyridines (DPP) - Amino acids linked DPP - Absorption and Emission - Quantum yield - HOMO-LUMO