A convenient four-component one-pot strategy toward the synthesis of pyrazolo[3,4-d]pyrimidines

An efficient one-pot synthesis of pyrazolo[3,4-d]pyrimidine derivatives by the four-component condensation of hydrazines, methylenemalononitriles, aldehydes and alcohols has been developed via two different reaction pathways. The structures of target products were characterized by IR spectroscopy, NMR ((1)H and (13)C) spectroscopy and HRMS (ESI) spectrometry. The crystal structure of 4-ethoxy-6-(2-nitrophenyl)-1-phenyl-1H-pyrazolo[3,4-d]pyrimidine was determined by single crystal X-ray diffraction.