Crystal and molecular structure of three biologically active nitroindazoles

Abstract 3-Bromo-1-methyl-7-nitro-1 H -indazole ( 1 ), 3-bromo-2-methyl-7-nitro-2 H -indazole ( 2 ) and 3,7-dinitro-1(2) H -indazole ( 3 ) have been synthesized and characterized by X-ray diffraction, 13 C and 15 N NMR spectroscopy in solution and in solid-state. The dihedral angles obtained in the crystal structures are in good agreement with the molecular parameters calculated using DFT B3LYP calculations employing the 6-311++G(d,p) basis set. Compounds 1 and 2 present intermolecular halogen bonds between the bromine and the oxygen atoms of the nitro group and in compound 3 inter- and intramolecular hydrogen bonding exists.