Synthesis and Fluorescence Properties of Donor-Acceptor-Substituted Novel Dipyrazolo[3,4-b:3′,4′-d]Pyridines (DPP)

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 C 4 position in the aryl ring changed the absorption and emission λ max .