2,6-Dimeth-oxy-9,10-anthraquinone

Crystal structure of 2-(tert-pentyl)anthracene-9,10-dione, C19H18O2

C19H18O2, orthorhombic, Pbca (no. 61), a = 11.017(5) Å, b = 12.140(5) Å, c = 23.346(10) Å, V = 3122(2) Å3, Z = 8, R gt (F) = 0.0498, wR ref (F2) = 0.1450, T = 296(2) K.

Crystal structures of 1-hy-droxy-4-prop-yloxy-9,10-anthra-quinone and its acetyl derivative

1-Hy-droxy-4-prop-yloxy-9,10-anthra-quinone, C17H14O4, (I), and its acetyl derivative, 4-acet-yloxy-4-prop-yloxy-9,10-anthra-quinone, C19H16O5, (II), were synthesized from the commercially available dye quinizarin. In both compounds, the anthra-quinone frameworks are close to planarity. There is a large difference in the conformation of the prop-yloxy group; the mol-ecule of (I) adopts a gauche conformation [O-C-C-C = -64.4 (2)°], although the mol-ecule of (II) takes a trans-planar conformation (zigzag) [O-C-C-C = 176.1 (3)°]. In the mol-ecule of (I), there is an intra-molecular O-H⋯O hydrogen bond. In both crystals, the mol-ecules are linked by C-H ⋯O hydrogen bonds. A difference in the mol-ecular arrangements of (I) and (II) is found along the stacking directions.

1,4-Dihydroxy-2,3-dinitro-9,10-anthraquinone

In the title compound, C14H6N2O8, the anthraquinone unit is essentially planar [maximum deviation = 0.0645 (10) Å], and there are two intramolecular O–H...O hydrogen bonds formingS(6) motifs. The planes of the two nitro substituents make dihedral angles of 54.77 (8) and 55.60 (3)° with the anthraquinone ring system. In the crystal, molecules are linked by short intermolecular O...O contacts, leading to a three-dimensional network structure.

4-(3-Bromopropyloxy)-1-hydroxy-9,10-anthraquinone

In the molecule of the title compound, C17H13BrO4, the anthraquinone ring system is slightly bent, with a dihedral angle of 169.99 (7)° between the planes of the two benzene rings. The side chain (O—C—C—C—Br) has agauche–gaucheconformation, as indicated by the O—C—C—C and C—C—C—Br torsion angles of −66.9 (2) and −65.8 (2)°, respectively. In addition, there is an intramolecular O—H...O hydrogen bond enclosing anS(6) ring motif. The hydrogen-bond donor is bifurcated; in the crystal, a pair of O—H...O hydrogen bonds connects two molecules, forming an inversion dimer with anR22(12) ring motif.