Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680703214X/nc2044sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S160053680703214X/nc2044Isup2.hkl |
CCDC reference: 657719
The title compound was prepared according to a literature procedure (Cassis et al., 1985). Single crystals of (I) suitable for X-ray data collection were obtained by slow evaporation from a solution of methanol:DCM (1:1). m.p.: 501–502 K.
The methyl H atoms were positioned with idealized geometry using a riding model with C—H = 0.96 Å. The other H atoms were located in difference map, and their positional parameters were refined freely [N—H = 0.85 (2) Å, O—H = 0.78 (2) Å and C—H = 0.87 (2)–1.00 (2) Å]. Uiso(H) values were set to 1.2Ueq (1.5Ueq for methyl) of the parent atom.
Aminoquinolines are important constituents in a variety of pharmaceutically important compound classes, most notably perhaps the antimalarials quinine, chloroquine, and their derivatives (Storz, 2004). On the other hands, Meldrum's acid and its derivatives serve as key intermediates for the synthesis of heterocyclic compounds with pharmacological activity (Gaber & McNab, 2001). In order to investigate the structure-function relationships and develop more effective antiparasitic drugs based on nitrogen heterocyclic derivatives (da Silva et al., 2007; da Silva et al., 2002), we report here the crystal structure of the title compound (I).
In (I), the 1,3-dioxane-4,6-dione ring is an envelope conformation with C13 in the flap position. The quinoline ring system, with the OH group, is nearly planar with maximum deviations from the mean plane of -0.0127 (9) Å for atom N1 and 0.0097 (9) Å for atom O3. The dihedral angle C11—C10—N2—C1 is -177.1 (1)° and the distances C1—N2 and C10—C11 indicate delocalization of the conjugated system. The amino H atom forms an intra- and an intermolecular contact to the carbonyl O4 atom. One intramolecular O—H···N and two intermolecular C—H···O hydrogen bonds were also observed. The packing diagram illustrates that two hydrogen-bonded molecules are related by an inversion centre building layers (Fig. 2). Details of the hydrogen-bonding parameters are given in Table 1.
For related literature, see: Cassis et al. (1985); Gaber & McNab (2001); da Silva et al. (2002, 2007); Storz (2004).
Data collection: CAD-4-PC Software (Enraf–Nonius, 1996); cell refinement: CAD-4-PC Software; data reduction: REDU4 (Stoe & Cie, 1987); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.
C16H14N2O5 | Z = 2 |
Mr = 314.29 | F(000) = 328 |
Triclinic, P1 | Dx = 1.379 Mg m−3 |
Hall symbol: -P 1 | Cu Kα radiation, λ = 1.54180 Å |
a = 7.445 (2) Å | Cell parameters from 25 reflections |
b = 8.440 (2) Å | θ = 5.6–25.2° |
c = 12.906 (3) Å | µ = 0.88 mm−1 |
α = 77.31 (1)° | T = 299 K |
β = 86.81 (2)° | Prism, colourless |
γ = 73.15 (1)° | 0.60 × 0.40 × 0.33 mm |
V = 757.2 (3) Å3 |
Enraf–Nonius CAD4 diffractometer | Rint = 0.053 |
Radiation source: fine-focus sealed tube | θmax = 66.9°, θmin = 3.5° |
Graphite monochromator | h = −8→8 |
ω/2θ scans | k = −10→10 |
5325 measured reflections | l = −15→15 |
2704 independent reflections | 3 standard reflections every 120 min |
2436 reflections with I > 2σ(I) | intensity decay: 1.0% |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.046 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.120 | w = 1/[σ2(Fo2) + (0.0542P)2 + 0.1625P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max = 0.002 |
2704 reflections | Δρmax = 0.27 e Å−3 |
233 parameters | Δρmin = −0.18 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0292 (18) |
C16H14N2O5 | γ = 73.15 (1)° |
Mr = 314.29 | V = 757.2 (3) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.445 (2) Å | Cu Kα radiation |
b = 8.440 (2) Å | µ = 0.88 mm−1 |
c = 12.906 (3) Å | T = 299 K |
α = 77.31 (1)° | 0.60 × 0.40 × 0.33 mm |
β = 86.81 (2)° |
Enraf–Nonius CAD4 diffractometer | Rint = 0.053 |
5325 measured reflections | 3 standard reflections every 120 min |
2704 independent reflections | intensity decay: 1.0% |
2436 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.046 | 0 restraints |
wR(F2) = 0.120 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.08 | Δρmax = 0.27 e Å−3 |
2704 reflections | Δρmin = −0.18 e Å−3 |
233 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.87562 (18) | 0.18229 (16) | 1.03493 (11) | 0.0356 (3) | |
C2 | 0.8419 (2) | 0.11498 (19) | 1.14199 (12) | 0.0433 (4) | |
H2 | 0.742 (3) | 0.061 (2) | 1.1559 (13) | 0.052* | |
C3 | 0.9522 (2) | 0.1279 (2) | 1.21805 (12) | 0.0465 (4) | |
H3 | 0.936 (3) | 0.084 (2) | 1.2920 (15) | 0.056* | |
C4 | 1.0967 (2) | 0.20732 (18) | 1.18985 (11) | 0.0415 (3) | |
C5 | 1.2181 (3) | 0.2261 (2) | 1.26336 (14) | 0.0532 (4) | |
H5 | 1.203 (3) | 0.191 (2) | 1.3366 (16) | 0.064* | |
C6 | 1.3538 (2) | 0.3041 (2) | 1.22804 (15) | 0.0559 (4) | |
H6 | 1.442 (3) | 0.319 (2) | 1.2787 (16) | 0.067* | |
C7 | 1.3758 (2) | 0.3669 (2) | 1.11993 (14) | 0.0493 (4) | |
H7 | 1.471 (3) | 0.422 (2) | 1.0951 (14) | 0.059* | |
C8 | 1.26047 (19) | 0.34956 (17) | 1.04695 (12) | 0.0402 (3) | |
C9 | 1.11806 (18) | 0.26817 (16) | 1.08037 (11) | 0.0358 (3) | |
C10 | 0.7677 (2) | 0.23140 (17) | 0.85433 (11) | 0.0391 (3) | |
H10 | 0.855 (3) | 0.281 (2) | 0.8346 (13) | 0.047* | |
C11 | 0.65092 (19) | 0.22806 (17) | 0.77695 (11) | 0.0384 (3) | |
C12 | 0.50124 (19) | 0.14834 (17) | 0.80186 (10) | 0.0367 (3) | |
C13 | 0.3749 (2) | 0.2999 (2) | 0.62899 (11) | 0.0469 (4) | |
C14 | 0.6902 (2) | 0.2936 (2) | 0.66727 (12) | 0.0484 (4) | |
C15 | 0.2853 (3) | 0.2547 (3) | 0.54213 (13) | 0.0674 (5) | |
H15A | 0.2819 | 0.3378 | 0.4776 | 0.101* | |
H15B | 0.1598 | 0.2525 | 0.5620 | 0.101* | |
H15C | 0.3572 | 0.1452 | 0.5314 | 0.101* | |
C16 | 0.2690 (3) | 0.4675 (2) | 0.65367 (14) | 0.0610 (5) | |
H16A | 0.3288 | 0.4863 | 0.7120 | 0.091* | |
H16B | 0.1424 | 0.4673 | 0.6724 | 0.091* | |
H16C | 0.2679 | 0.5561 | 0.5924 | 0.091* | |
N1 | 1.00832 (15) | 0.25491 (13) | 1.00330 (9) | 0.0360 (3) | |
N2 | 0.75720 (16) | 0.16946 (14) | 0.95745 (9) | 0.0384 (3) | |
H2N | 0.677 (3) | 0.116 (2) | 0.9798 (13) | 0.046* | |
O1 | 0.38313 (15) | 0.16567 (14) | 0.72143 (8) | 0.0478 (3) | |
O2 | 0.56184 (16) | 0.30024 (16) | 0.59423 (8) | 0.0546 (3) | |
O3 | 1.27855 (16) | 0.41060 (14) | 0.94136 (9) | 0.0502 (3) | |
H3O | 1.205 (3) | 0.386 (3) | 0.9114 (16) | 0.060* | |
O4 | 0.47832 (15) | 0.06465 (13) | 0.88781 (8) | 0.0445 (3) | |
O5 | 0.82846 (18) | 0.3362 (2) | 0.63562 (10) | 0.0747 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0278 (6) | 0.0356 (7) | 0.0447 (7) | −0.0111 (5) | −0.0029 (5) | −0.0076 (5) |
C2 | 0.0353 (7) | 0.0496 (8) | 0.0488 (8) | −0.0221 (6) | −0.0007 (6) | −0.0043 (6) |
C3 | 0.0444 (8) | 0.0572 (9) | 0.0408 (8) | −0.0239 (7) | −0.0012 (6) | −0.0036 (6) |
C4 | 0.0354 (7) | 0.0445 (7) | 0.0471 (8) | −0.0145 (6) | −0.0034 (6) | −0.0096 (6) |
C5 | 0.0518 (9) | 0.0652 (10) | 0.0493 (9) | −0.0250 (8) | −0.0077 (7) | −0.0131 (7) |
C6 | 0.0468 (9) | 0.0632 (10) | 0.0678 (11) | −0.0230 (8) | −0.0127 (8) | −0.0217 (8) |
C7 | 0.0353 (8) | 0.0478 (8) | 0.0728 (11) | −0.0201 (6) | −0.0014 (7) | −0.0182 (7) |
C8 | 0.0305 (7) | 0.0364 (7) | 0.0559 (8) | −0.0117 (5) | 0.0026 (6) | −0.0120 (6) |
C9 | 0.0269 (6) | 0.0348 (6) | 0.0475 (8) | −0.0098 (5) | −0.0022 (5) | −0.0107 (5) |
C10 | 0.0305 (7) | 0.0401 (7) | 0.0481 (8) | −0.0147 (6) | −0.0007 (6) | −0.0060 (6) |
C11 | 0.0324 (7) | 0.0423 (7) | 0.0411 (7) | −0.0151 (6) | −0.0007 (5) | −0.0038 (6) |
C12 | 0.0361 (7) | 0.0406 (7) | 0.0359 (7) | −0.0157 (5) | −0.0030 (5) | −0.0061 (5) |
C13 | 0.0392 (8) | 0.0658 (9) | 0.0350 (7) | −0.0225 (7) | −0.0019 (6) | 0.0012 (6) |
C14 | 0.0371 (8) | 0.0610 (9) | 0.0463 (8) | −0.0198 (7) | 0.0024 (6) | −0.0028 (7) |
C15 | 0.0645 (11) | 0.1003 (14) | 0.0435 (9) | −0.0365 (11) | −0.0114 (8) | −0.0077 (9) |
C16 | 0.0528 (10) | 0.0647 (10) | 0.0560 (10) | −0.0123 (8) | −0.0026 (8) | 0.0017 (8) |
N1 | 0.0290 (6) | 0.0366 (6) | 0.0438 (6) | −0.0120 (4) | −0.0005 (5) | −0.0075 (5) |
N2 | 0.0311 (6) | 0.0424 (6) | 0.0447 (7) | −0.0175 (5) | −0.0040 (5) | −0.0055 (5) |
O1 | 0.0475 (6) | 0.0612 (6) | 0.0404 (6) | −0.0314 (5) | −0.0096 (4) | 0.0017 (4) |
O2 | 0.0433 (6) | 0.0845 (8) | 0.0362 (6) | −0.0261 (6) | 0.0033 (4) | −0.0037 (5) |
O3 | 0.0437 (6) | 0.0561 (6) | 0.0573 (7) | −0.0265 (5) | 0.0087 (5) | −0.0110 (5) |
O4 | 0.0484 (6) | 0.0523 (6) | 0.0381 (5) | −0.0292 (5) | −0.0038 (4) | 0.0008 (4) |
O5 | 0.0494 (7) | 0.1174 (11) | 0.0581 (7) | −0.0452 (7) | 0.0062 (6) | 0.0067 (7) |
C1—N1 | 1.3095 (18) | C10—H10 | 0.867 (19) |
C1—N2 | 1.4107 (18) | C11—C12 | 1.4483 (19) |
C1—C2 | 1.412 (2) | C11—C14 | 1.449 (2) |
C2—C3 | 1.356 (2) | C12—O4 | 1.2096 (17) |
C2—H2 | 0.97 (2) | C12—O1 | 1.3537 (17) |
C3—C4 | 1.416 (2) | C13—O2 | 1.4392 (18) |
C3—H3 | 0.959 (18) | C13—O1 | 1.4437 (17) |
C4—C5 | 1.409 (2) | C13—C16 | 1.499 (2) |
C4—C9 | 1.410 (2) | C13—C15 | 1.505 (2) |
C5—C6 | 1.366 (3) | C14—O5 | 1.208 (2) |
C5—H5 | 0.94 (2) | C14—O2 | 1.360 (2) |
C6—C7 | 1.398 (3) | C15—H15A | 0.9600 |
C6—H6 | 1.00 (2) | C15—H15B | 0.9600 |
C7—C8 | 1.367 (2) | C15—H15C | 0.9600 |
C7—H7 | 0.96 (2) | C16—H16A | 0.9600 |
C8—O3 | 1.3608 (19) | C16—H16B | 0.9600 |
C8—C9 | 1.4224 (19) | C16—H16C | 0.9600 |
C9—N1 | 1.3644 (18) | N2—H2N | 0.85 (2) |
C10—N2 | 1.3255 (19) | O3—H3O | 0.79 (2) |
C10—C11 | 1.370 (2) | ||
N1—C1—N2 | 118.34 (12) | C12—C11—C14 | 119.95 (13) |
N1—C1—C2 | 124.55 (13) | O4—C12—O1 | 118.43 (12) |
N2—C1—C2 | 117.11 (12) | O4—C12—C11 | 124.72 (13) |
C3—C2—C1 | 118.21 (13) | O1—C12—C11 | 116.81 (11) |
C3—C2—H2 | 124.4 (10) | O2—C13—O1 | 109.88 (12) |
C1—C2—H2 | 117.4 (10) | O2—C13—C16 | 110.65 (14) |
C2—C3—C4 | 120.36 (14) | O1—C13—C16 | 110.18 (12) |
C2—C3—H3 | 122.0 (12) | O2—C13—C15 | 106.47 (13) |
C4—C3—H3 | 117.7 (12) | O1—C13—C15 | 106.14 (14) |
C5—C4—C9 | 119.49 (14) | C16—C13—C15 | 113.36 (15) |
C5—C4—C3 | 124.25 (14) | O5—C14—O2 | 118.07 (14) |
C9—C4—C3 | 116.25 (13) | O5—C14—C11 | 125.82 (15) |
C6—C5—C4 | 119.78 (16) | O2—C14—C11 | 116.05 (13) |
C6—C5—H5 | 119.4 (14) | C13—C15—H15A | 109.5 |
C4—C5—H5 | 120.7 (14) | C13—C15—H15B | 109.5 |
C5—C6—C7 | 121.53 (15) | H15A—C15—H15B | 109.5 |
C5—C6—H6 | 121.2 (12) | C13—C15—H15C | 109.5 |
C7—C6—H6 | 117.3 (12) | H15A—C15—H15C | 109.5 |
C8—C7—C6 | 119.85 (15) | H15B—C15—H15C | 109.5 |
C8—C7—H7 | 118.6 (11) | C13—C16—H16A | 109.5 |
C6—C7—H7 | 121.6 (11) | C13—C16—H16B | 109.5 |
O3—C8—C7 | 120.85 (14) | H16A—C16—H16B | 109.5 |
O3—C8—C9 | 118.76 (13) | C13—C16—H16C | 109.5 |
C7—C8—C9 | 120.38 (14) | H16A—C16—H16C | 109.5 |
N1—C9—C4 | 123.75 (12) | H16B—C16—H16C | 109.5 |
N1—C9—C8 | 117.29 (12) | C1—N1—C9 | 116.85 (12) |
C4—C9—C8 | 118.96 (13) | C10—N2—C1 | 124.05 (13) |
N2—C10—C11 | 125.99 (14) | C10—N2—H2N | 119.6 (11) |
N2—C10—H10 | 116.6 (11) | C1—N2—H2N | 116.4 (12) |
C11—C10—H10 | 117.4 (11) | C12—O1—C13 | 118.49 (11) |
C10—C11—C12 | 121.53 (13) | C14—O2—C13 | 118.71 (11) |
C10—C11—C14 | 118.32 (13) | C8—O3—H3O | 107.0 (15) |
N1—C1—C2—C3 | 1.0 (2) | C10—C11—C12—O1 | 174.03 (12) |
N2—C1—C2—C3 | −179.08 (13) | C14—C11—C12—O1 | −11.3 (2) |
C1—C2—C3—C4 | 0.1 (2) | C10—C11—C14—O5 | 8.0 (3) |
C2—C3—C4—C5 | −179.85 (15) | C12—C11—C14—O5 | −166.78 (17) |
C2—C3—C4—C9 | −0.7 (2) | C10—C11—C14—O2 | −174.86 (13) |
C9—C4—C5—C6 | 0.6 (2) | C12—C11—C14—O2 | 10.3 (2) |
C3—C4—C5—C6 | 179.72 (16) | N2—C1—N1—C9 | 178.78 (10) |
C4—C5—C6—C7 | 0.2 (3) | C2—C1—N1—C9 | −1.3 (2) |
C5—C6—C7—C8 | −0.5 (3) | C4—C9—N1—C1 | 0.58 (19) |
C6—C7—C8—O3 | 179.61 (13) | C8—C9—N1—C1 | −178.91 (11) |
C6—C7—C8—C9 | 0.1 (2) | C11—C10—N2—C1 | −177.11 (13) |
C5—C4—C9—N1 | 179.58 (13) | N1—C1—N2—C10 | −2.3 (2) |
C3—C4—C9—N1 | 0.4 (2) | C2—C1—N2—C10 | 177.76 (12) |
C5—C4—C9—C8 | −0.9 (2) | O4—C12—O1—C13 | 163.07 (13) |
C3—C4—C9—C8 | 179.84 (12) | C11—C12—O1—C13 | −18.90 (18) |
O3—C8—C9—N1 | 0.60 (18) | O2—C13—O1—C12 | 47.43 (17) |
C7—C8—C9—N1 | −179.88 (12) | C16—C13—O1—C12 | −74.74 (17) |
O3—C8—C9—C4 | −178.92 (11) | C15—C13—O1—C12 | 162.17 (13) |
C7—C8—C9—C4 | 0.6 (2) | O5—C14—O2—C13 | −161.71 (16) |
N2—C10—C11—C12 | −1.8 (2) | C11—C14—O2—C13 | 21.0 (2) |
N2—C10—C11—C14 | −176.57 (13) | O1—C13—O2—C14 | −48.65 (18) |
C10—C11—C12—O4 | −8.1 (2) | C16—C13—O2—C14 | 73.23 (17) |
C14—C11—C12—O4 | 166.58 (13) | C15—C13—O2—C14 | −163.18 (14) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2N···O4 | 0.85 (2) | 2.140 (19) | 2.7428 (17) | 127.6 (14) |
N2—H2N···O4i | 0.85 (2) | 2.498 (18) | 3.2943 (17) | 156.2 (15) |
O3—H3O···N1 | 0.79 (2) | 2.22 (2) | 2.7028 (16) | 120.0 (18) |
C2—H2···O1i | 0.97 (2) | 2.564 (19) | 3.4151 (19) | 146.6 (14) |
C2—H2···O4i | 0.97 (2) | 2.35 (2) | 3.2533 (19) | 155.4 (14) |
Symmetry code: (i) −x+1, −y, −z+2. |
Experimental details
Crystal data | |
Chemical formula | C16H14N2O5 |
Mr | 314.29 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 299 |
a, b, c (Å) | 7.445 (2), 8.440 (2), 12.906 (3) |
α, β, γ (°) | 77.31 (1), 86.81 (2), 73.15 (1) |
V (Å3) | 757.2 (3) |
Z | 2 |
Radiation type | Cu Kα |
µ (mm−1) | 0.88 |
Crystal size (mm) | 0.60 × 0.40 × 0.33 |
Data collection | |
Diffractometer | Enraf–Nonius CAD4 |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5325, 2704, 2436 |
Rint | 0.053 |
(sin θ/λ)max (Å−1) | 0.597 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.046, 0.120, 1.08 |
No. of reflections | 2704 |
No. of parameters | 233 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.27, −0.18 |
Computer programs: CAD-4-PC Software (Enraf–Nonius, 1996), CAD-4-PC Software, REDU4 (Stoe & Cie, 1987), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), SHELXL97.
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2N···O4 | 0.85 (2) | 2.140 (19) | 2.7428 (17) | 127.6 (14) |
N2—H2N···O4i | 0.85 (2) | 2.498 (18) | 3.2943 (17) | 156.2 (15) |
O3—H3O···N1 | 0.79 (2) | 2.22 (2) | 2.7028 (16) | 120.0 (18) |
C2—H2···O1i | 0.97 (2) | 2.564 (19) | 3.4151 (19) | 146.6 (14) |
C2—H2···O4i | 0.97 (2) | 2.35 (2) | 3.2533 (19) | 155.4 (14) |
Symmetry code: (i) −x+1, −y, −z+2. |
Aminoquinolines are important constituents in a variety of pharmaceutically important compound classes, most notably perhaps the antimalarials quinine, chloroquine, and their derivatives (Storz, 2004). On the other hands, Meldrum's acid and its derivatives serve as key intermediates for the synthesis of heterocyclic compounds with pharmacological activity (Gaber & McNab, 2001). In order to investigate the structure-function relationships and develop more effective antiparasitic drugs based on nitrogen heterocyclic derivatives (da Silva et al., 2007; da Silva et al., 2002), we report here the crystal structure of the title compound (I).
In (I), the 1,3-dioxane-4,6-dione ring is an envelope conformation with C13 in the flap position. The quinoline ring system, with the OH group, is nearly planar with maximum deviations from the mean plane of -0.0127 (9) Å for atom N1 and 0.0097 (9) Å for atom O3. The dihedral angle C11—C10—N2—C1 is -177.1 (1)° and the distances C1—N2 and C10—C11 indicate delocalization of the conjugated system. The amino H atom forms an intra- and an intermolecular contact to the carbonyl O4 atom. One intramolecular O—H···N and two intermolecular C—H···O hydrogen bonds were also observed. The packing diagram illustrates that two hydrogen-bonded molecules are related by an inversion centre building layers (Fig. 2). Details of the hydrogen-bonding parameters are given in Table 1.