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 lambda(max).