One-pot synthesis of new 6-pyrrolyl- N -alkyl-indazoles from reductive coupling of N -alkyl-6-nitroindazoles and 2,5-hexadione
摘要:
One-pot synthesis of 6-pyrrolyl-N-alkyl-indazoles by the reductive coupling of N-alkyl-6-nitroindazoles and 2,5-hexadione was investigated in the presence of different reducing agents (SnCl2/AcOH and In/AcOH in THF). Indazoles 5a-h and 6a-h were obtained in good to excellent yields (74-95%) and characterized by elemental analysis, NMR, and single crystal X-ray diffraction. The same synthetic approach was also used to obtain 5-pyrrolyl-N-alkyl-indazoles. (C) 2015 Elsevier Ltd. All rights reserved.