Experimental Crystal data

R factor = 0.034; wR factor = 0.100; data-to-parameter ratio = 15.5. The fused five- and six-membered rings in the title molecule, C10H9N3O2, are essentially coplanar, the largest deviation from the mean plane being 0.012 (1) A ̊ for the C atom linked to the nitro group. The fused-ring system makes a dihedral angle of 11.34 (6) with the nitro group, leading to a syn-periplanar conformation. The plane through the atoms forming the allyl group is nearly perpendicular to the indazole fused-ring system, as indicated by the dihedral angle of 73.3 (5). In the crystal, each molecule is linked to its symmetry equivalent about the center of inversion by pairs of non-classical C—H O hydrogen bonds, forming an extended tape motif parallel to the (121) plane. Related literature For the pharmacological and biochemical properties of substituted indazoles, see: Saczewski et al. (2008); Jones et al. (2009); Bouissane et al. (2006). For compounds with simila