organic compounds
3,3′-Dihydroxy-6,6′-bis(hydroxymethyl)-2,2′-(pentane-1,1-diyl)di-4H-pyran-4-one
aCollege of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, People's Republic of China, and bSchool of Food Science and Biotechnology, Zhejiang GongShang University, Hangzhou, Zhejiang 310012, People's Republic of China
*Correspondence e-mail: taozhou@zjgsu.edu.cn
In the title molecule, C17H20O8, the two pyran rings form a dihedral angle of 61.2 (2)°. The two hydroxymethyl groups are each disordered over two sets of sites in a 0.764 (3):0.236 (3) ratio. In the crystal, O—H⋯O hydrogen bonds link the molecules into layers parallel to the ac plane.
Related literature
For the biological properties of kojic acid, see: Kobayashi et al. (1995). For related structures, see: Nurchi et al. (2010); Kakkar & Singh (2011); Lokaj et al. (1991). For the preparation of the title compound, see: Barham & Nathan Reed (1938).
Experimental
Crystal data
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Refinement
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Data collection: PROCESS-AUTO (Rigaku, 2006); cell PROCESS-AUTO; data reduction: CrystalStructure (Rigaku, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia,1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supporting information
10.1107/S1600536812010276/cv5255sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812010276/cv5255Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812010276/cv5255Isup3.cml
To a solution of 5-hydroxy-(2-hydroxymethyl)-4H-pyran-4-one (kojic acid) (1.42 g, 10 mmol), sodium carbonate (1.06 g, 10 mmol) in water (10 ml) and methanol (10 ml) was added pentanal (10 mmol) at 343k with stirring. The stirring was continued for 3 h at that temperature. After removal of about half volume of the solvent, the soltion was neutrilized to pH=1 with concentrated hydrochloride. The crude product was obtained by filtration as an off-white solid (1.32, 75%), which was recrystallized from dichloromethane solution, giving colorless crystals of the title compound suitable for X-ray diffraction. 1H NMR (400 MHz DMSO) / d 0.84 (t, J = 6.8 Hz, 3H), 1.21 (m, 4H), 1.29 (2, m), 1.92 (m, 2H), 4.28 (s, 4H), 4.68 (t, J = 8.0 Hz, 1H), 5.62 (s, 2H), 6.28 (s, 2H), 9.03 (s, 2H).
H atoms were placed in calculated positions with O—H = 0.82 and C—H = 0.93–0.98 Å, and included in the
in riding model, with Uiso(H)= 1.2 - 1.5 Ueq(carrier atom). Atoms O4 and O8 of hydroxyl groups were treated as disordered over two positions - A and B, respectively - with the occupancies refined to 0.764 (3) and 0.236 (3), respectively.Kojic acid possesses appreciable inhibitory activity against tyrosinase, a key enzyme in the biosynthesis of melanin, due to its ability to chelate copper in the active site of this enzyme. Thus kojic acid inhibits the production of melanin pigment, consequently being used in cosmetic. Therefore, in an attempt to seek potent tyrosinase inhibitors, the derivatives of kojic acid have been widely investigated (Kobayashi et al., 1995).There were little attentation to
of kojic and derivatives.The similar of Kojic acid have been reported on 5-hydroxy-2-(hydroxymenthyl) -4H-pyran-one (Lokaj et al., 1991; Kakkar et al., 2011) and 6,6'-methylenebis (5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one) (Nurchi et al., 2010). Herein, we report the of the title compound (I).In (I) (Fig. 1), two pyranone rings are planar forming the dihedral angle of 61.2 (2)°. Hydroxyl groups are almost coplanar with their linked pyranone rings forming the torsion angles O2—C3—C4—O3 of -0.10° and O6—C10—C9—O5 of 1.24°.
Intermolecular hydrogen bonds O3—H3···O2i and O5—H5···O6ii (Table 1) link molecules into zigzag chains along the c axis. Further, intermolecular hydrogen bonds O4A—H4···O2iii and O8A—H8A···O6iii (Table 1) link all of the components of the structure into layers parallel to ac plane.
For the biological properties of kojic acid, see: Kobayashi et al. (1995). For related structures, see: Nurchi et al. (2010); Kakkar & Singh (2011); Lokaj et al. (1991). For the preparation of the title compound, see: Barham & Nathan Reed (1938).
Data collection: PROCESS-AUTO (Rigaku, 2006); cell
PROCESS-AUTO (Rigaku, 2006); data reduction: CrystalStructure (Rigaku, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia,1997); software used to prepare material for publication: WinGX (Farrugia, 1999).Fig. 1. Molecular structure of (I) showing atom-labelling scheme and displacement ellipsoids at 50% probability level. Only major components of the disordered groups are shown. | |
Fig. 2. A portion of the crystal packing of (I) with hydrogen bonds shown by dashed lines [symmetry codes: (i) -x, 1 - y, -z; (ii) -x, 1 - y, 1 - z; (iii) 1 + x, y, z]. H atoms not involved in hydrogen bonding have been omitted for clarity. |
C17H20O8 | Z = 2 |
Mr = 352.33 | F(000) = 372 |
Triclinic, P1 | Dx = 1.376 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 6.4234 (3) Å | Cell parameters from 6451 reflections |
b = 9.2394 (4) Å | θ = 3.3–27.4° |
c = 15.8494 (7) Å | µ = 0.11 mm−1 |
α = 79.993 (1)° | T = 296 K |
β = 86.689 (2)° | Chunk, yellow |
γ = 66.622 (1)° | 0.49 × 0.47 × 0.33 mm |
V = 850.22 (7) Å3 |
Rigaku R-AXIS RAPID/ZJUG diffractometer | 3840 independent reflections |
Radiation source: rotating anode | 2907 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.017 |
Detector resolution: 10.00 pixels mm-1 | θmax = 27.4°, θmin = 3.3° |
ω scans | h = −8→8 |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −11→10 |
Tmin = 0.938, Tmax = 0.965 | l = −20→20 |
8442 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.043 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.120 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0554P)2 + 0.2871P] where P = (Fo2 + 2Fc2)/3 |
3840 reflections | (Δ/σ)max < 0.001 |
251 parameters | Δρmax = 0.30 e Å−3 |
6 restraints | Δρmin = −0.30 e Å−3 |
C17H20O8 | γ = 66.622 (1)° |
Mr = 352.33 | V = 850.22 (7) Å3 |
Triclinic, P1 | Z = 2 |
a = 6.4234 (3) Å | Mo Kα radiation |
b = 9.2394 (4) Å | µ = 0.11 mm−1 |
c = 15.8494 (7) Å | T = 296 K |
α = 79.993 (1)° | 0.49 × 0.47 × 0.33 mm |
β = 86.689 (2)° |
Rigaku R-AXIS RAPID/ZJUG diffractometer | 3840 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 2907 reflections with I > 2σ(I) |
Tmin = 0.938, Tmax = 0.965 | Rint = 0.017 |
8442 measured reflections |
R[F2 > 2σ(F2)] = 0.043 | 6 restraints |
wR(F2) = 0.120 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.30 e Å−3 |
3840 reflections | Δρmin = −0.30 e Å−3 |
251 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 | Occ. (<1) | |
O1 | 0.70599 (16) | 0.37814 (12) | 0.33797 (6) | 0.0343 (2) | |
O2 | 0.24351 (19) | 0.37234 (15) | 0.52086 (7) | 0.0489 (3) | |
O3 | 0.10419 (18) | 0.56659 (15) | 0.36549 (7) | 0.0499 (3) | |
H3 | 0.0303 | 0.5617 | 0.4091 | 0.075* | |
O5 | 0.10800 (19) | 0.56285 (16) | 0.11434 (8) | 0.0534 (3) | |
H5 | 0.0366 | 0.5594 | 0.0740 | 0.080* | |
O6 | 0.2475 (2) | 0.35803 (17) | −0.00299 (8) | 0.0562 (3) | |
O7 | 0.70230 (17) | 0.35409 (12) | 0.16422 (6) | 0.0381 (3) | |
O4A | 1.1115 (3) | 0.1209 (2) | 0.50117 (12) | 0.0591 (5) | 0.764 (3) |
H4A | 1.1380 | 0.1883 | 0.5209 | 0.089* | 0.764 (3) |
O8A | 1.1284 (3) | 0.0846 (2) | 0.04825 (13) | 0.0635 (6) | 0.764 (3) |
H8A | 1.1580 | 0.1543 | 0.0169 | 0.095* | 0.764 (3) |
O4B | 1.0634 (8) | 0.0558 (6) | 0.3693 (3) | 0.0474 (14) | 0.236 (3) |
H4B | 1.0161 | −0.0084 | 0.3968 | 0.071* | 0.236 (3) |
O8B | 1.061 (2) | −0.0030 (16) | 0.0999 (9) | 0.153 (5) | 0.236 (3) |
H8B | 1.0323 | 0.0071 | 0.0490 | 0.230* | 0.236 (3) |
C1 | 0.7734 (2) | 0.28416 (17) | 0.41491 (9) | 0.0348 (3) | |
C2 | 0.6275 (3) | 0.27937 (18) | 0.47792 (9) | 0.0375 (3) | |
H2 | 0.6811 | 0.2135 | 0.5301 | 0.045* | |
C3 | 0.3903 (2) | 0.37414 (17) | 0.46608 (9) | 0.0347 (3) | |
C4 | 0.3252 (2) | 0.47378 (17) | 0.38243 (9) | 0.0329 (3) | |
C5 | 0.4816 (2) | 0.47156 (16) | 0.32159 (8) | 0.0302 (3) | |
C6 | 1.0238 (3) | 0.1844 (2) | 0.41614 (11) | 0.0474 (4) | |
H6A | 1.0525 | 0.0971 | 0.3848 | 0.057* | 0.764 (3) |
H6B | 1.1022 | 0.2494 | 0.3873 | 0.057* | 0.764 (3) |
H6C | 1.1034 | 0.2466 | 0.3877 | 0.057* | 0.236 (3) |
H6D | 1.0788 | 0.1461 | 0.4755 | 0.057* | 0.236 (3) |
C7 | 0.4372 (2) | 0.56545 (17) | 0.23201 (8) | 0.0331 (3) | |
H7 | 0.2759 | 0.6362 | 0.2279 | 0.040* | |
C8 | 0.4808 (2) | 0.45696 (17) | 0.16640 (8) | 0.0332 (3) | |
C9 | 0.3266 (3) | 0.46005 (18) | 0.11099 (9) | 0.0363 (3) | |
C10 | 0.3925 (3) | 0.35414 (19) | 0.04794 (9) | 0.0400 (3) | |
C11 | 0.6259 (3) | 0.24898 (19) | 0.04981 (10) | 0.0437 (4) | |
H11 | 0.6790 | 0.1780 | 0.0109 | 0.052* | |
C12 | 0.7702 (3) | 0.25138 (18) | 0.10724 (10) | 0.0407 (4) | |
C13 | 1.0161 (3) | 0.1441 (2) | 0.12089 (14) | 0.0593 (5) | |
H13A | 1.0933 | 0.2027 | 0.1416 | 0.071* | 0.764 (3) |
H13B | 1.0285 | 0.0544 | 0.1654 | 0.071* | 0.764 (3) |
H13C | 1.1133 | 0.1895 | 0.0883 | 0.071* | 0.236 (3) |
H13D | 1.0587 | 0.1215 | 0.1812 | 0.071* | 0.236 (3) |
C14 | 0.5730 (3) | 0.67220 (18) | 0.21157 (9) | 0.0396 (3) | |
H14A | 0.7336 | 0.6051 | 0.2178 | 0.047* | |
H14B | 0.5444 | 0.7244 | 0.1523 | 0.047* | |
C15 | 0.5152 (3) | 0.79877 (19) | 0.26837 (10) | 0.0421 (4) | |
H15A | 0.5501 | 0.7469 | 0.3275 | 0.050* | |
H15B | 0.3537 | 0.8638 | 0.2640 | 0.050* | |
C16 | 0.6444 (4) | 0.9060 (2) | 0.24434 (13) | 0.0565 (5) | |
H16A | 0.8057 | 0.8408 | 0.2504 | 0.068* | |
H16B | 0.6136 | 0.9542 | 0.1845 | 0.068* | |
C17 | 0.5856 (5) | 1.0365 (3) | 0.29752 (16) | 0.0846 (8) | |
H17A | 0.4309 | 1.1097 | 0.2863 | 0.127* | |
H17B | 0.6839 | 1.0927 | 0.2830 | 0.127* | |
H17C | 0.6046 | 0.9906 | 0.3572 | 0.127* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0301 (5) | 0.0425 (6) | 0.0298 (5) | −0.0143 (4) | 0.0034 (4) | −0.0054 (4) |
O2 | 0.0423 (6) | 0.0612 (7) | 0.0361 (6) | −0.0176 (6) | 0.0120 (5) | −0.0004 (5) |
O3 | 0.0323 (6) | 0.0651 (8) | 0.0361 (6) | −0.0075 (5) | 0.0071 (4) | 0.0030 (5) |
O5 | 0.0355 (6) | 0.0775 (9) | 0.0462 (7) | −0.0136 (6) | −0.0004 (5) | −0.0285 (6) |
O6 | 0.0540 (7) | 0.0746 (9) | 0.0452 (7) | −0.0240 (6) | −0.0054 (5) | −0.0247 (6) |
O7 | 0.0378 (6) | 0.0412 (6) | 0.0340 (5) | −0.0127 (5) | 0.0010 (4) | −0.0101 (4) |
O4A | 0.0509 (10) | 0.0545 (10) | 0.0667 (11) | −0.0207 (8) | −0.0180 (8) | 0.0091 (8) |
O8A | 0.0518 (10) | 0.0561 (11) | 0.0838 (14) | −0.0127 (9) | 0.0167 (9) | −0.0404 (10) |
O4B | 0.038 (3) | 0.037 (3) | 0.062 (3) | −0.008 (2) | 0.009 (2) | −0.014 (2) |
O8B | 0.153 (5) | 0.153 (5) | 0.154 (5) | −0.060 (2) | 0.0009 (10) | −0.0263 (13) |
C1 | 0.0354 (7) | 0.0357 (7) | 0.0338 (7) | −0.0140 (6) | −0.0016 (6) | −0.0066 (6) |
C2 | 0.0399 (8) | 0.0384 (8) | 0.0306 (7) | −0.0136 (6) | −0.0006 (6) | −0.0007 (6) |
C3 | 0.0393 (8) | 0.0364 (7) | 0.0302 (7) | −0.0170 (6) | 0.0054 (6) | −0.0066 (6) |
C4 | 0.0318 (7) | 0.0363 (7) | 0.0301 (7) | −0.0130 (6) | 0.0024 (5) | −0.0058 (6) |
C5 | 0.0312 (7) | 0.0334 (7) | 0.0282 (6) | −0.0141 (6) | 0.0012 (5) | −0.0071 (5) |
C6 | 0.0351 (8) | 0.0514 (9) | 0.0512 (9) | −0.0134 (7) | −0.0007 (7) | −0.0052 (8) |
C7 | 0.0350 (7) | 0.0381 (7) | 0.0256 (6) | −0.0136 (6) | 0.0025 (5) | −0.0064 (5) |
C8 | 0.0349 (7) | 0.0377 (7) | 0.0274 (6) | −0.0157 (6) | 0.0044 (5) | −0.0046 (6) |
C9 | 0.0369 (8) | 0.0450 (8) | 0.0283 (7) | −0.0179 (7) | 0.0036 (6) | −0.0067 (6) |
C10 | 0.0471 (9) | 0.0484 (9) | 0.0293 (7) | −0.0235 (7) | 0.0023 (6) | −0.0082 (6) |
C11 | 0.0541 (10) | 0.0420 (8) | 0.0358 (8) | −0.0171 (7) | 0.0047 (7) | −0.0140 (7) |
C12 | 0.0460 (9) | 0.0372 (8) | 0.0362 (8) | −0.0134 (7) | 0.0047 (6) | −0.0077 (6) |
C13 | 0.0489 (10) | 0.0527 (10) | 0.0658 (12) | −0.0064 (8) | 0.0031 (9) | −0.0169 (9) |
C14 | 0.0500 (9) | 0.0420 (8) | 0.0309 (7) | −0.0233 (7) | 0.0081 (6) | −0.0063 (6) |
C15 | 0.0520 (9) | 0.0409 (8) | 0.0358 (8) | −0.0207 (7) | 0.0033 (7) | −0.0075 (6) |
C16 | 0.0716 (12) | 0.0488 (10) | 0.0576 (11) | −0.0329 (9) | 0.0096 (9) | −0.0106 (8) |
C17 | 0.129 (2) | 0.0774 (15) | 0.0786 (15) | −0.0695 (16) | 0.0189 (15) | −0.0289 (12) |
O1—C1 | 1.3502 (17) | C6—H6B | 0.9700 |
O1—C5 | 1.3669 (16) | C6—H6C | 0.9553 |
O2—C3 | 1.2474 (17) | C6—H6D | 0.9795 |
O3—C4 | 1.3492 (17) | C7—C8 | 1.5069 (19) |
O3—H3 | 0.8200 | C7—C14 | 1.542 (2) |
O5—C9 | 1.3518 (18) | C7—H7 | 0.9800 |
O5—H5 | 0.8200 | C8—C9 | 1.350 (2) |
O6—C10 | 1.2531 (19) | C9—C10 | 1.448 (2) |
O7—C12 | 1.3529 (18) | C10—C11 | 1.426 (2) |
O7—C8 | 1.3641 (17) | C11—C12 | 1.345 (2) |
O4A—C6 | 1.424 (2) | C11—H11 | 0.9300 |
O4A—H4A | 0.8200 | C12—C13 | 1.499 (2) |
O4A—H6D | 0.4491 | C13—H13A | 0.9700 |
O8A—C13 | 1.399 (3) | C13—H13B | 0.9700 |
O8A—H8A | 0.8200 | C13—H13C | 0.9635 |
O8A—H13C | 1.2178 | C13—H13D | 0.9733 |
O4B—C6 | 1.439 (5) | C14—C15 | 1.516 (2) |
O4B—H4B | 0.8200 | C14—H14A | 0.9700 |
O8B—C13 | 1.369 (13) | C14—H14B | 0.9700 |
O8B—H8B | 0.8200 | C15—C16 | 1.517 (2) |
C1—C2 | 1.337 (2) | C15—H15A | 0.9700 |
C1—C6 | 1.503 (2) | C15—H15B | 0.9700 |
C2—C3 | 1.428 (2) | C16—C17 | 1.504 (3) |
C2—H2 | 0.9300 | C16—H16A | 0.9700 |
C3—C4 | 1.4541 (19) | C16—H16B | 0.9700 |
C4—C5 | 1.3484 (19) | C17—H17A | 0.9600 |
C5—C7 | 1.5073 (19) | C17—H17B | 0.9600 |
C6—H6A | 0.9700 | C17—H17C | 0.9600 |
C1—O1—C5 | 120.29 (11) | O6—C10—C11 | 124.42 (15) |
C4—O3—H3 | 109.5 | O6—C10—C9 | 120.11 (15) |
C9—O5—H5 | 109.5 | C11—C10—C9 | 115.47 (13) |
C12—O7—C8 | 120.36 (12) | C12—C11—C10 | 120.66 (14) |
C6—O4A—H4A | 109.5 | C12—C11—H11 | 119.7 |
H4A—O4A—H6D | 104.7 | C10—C11—H11 | 119.7 |
C13—O8A—H8A | 109.5 | C11—C12—O7 | 121.98 (14) |
H8A—O8A—H13C | 70.3 | C11—C12—C13 | 127.48 (15) |
C6—O4B—H4B | 109.5 | O7—C12—C13 | 110.50 (14) |
C13—O8B—H8B | 109.5 | O8B—C13—O8A | 52.8 (6) |
C2—C1—O1 | 122.32 (13) | O8B—C13—C12 | 111.3 (6) |
C2—C1—C6 | 126.71 (14) | O8A—C13—C12 | 115.07 (17) |
O1—C1—C6 | 110.89 (13) | O8B—C13—H13A | 140.2 |
C1—C2—C3 | 120.82 (13) | O8A—C13—H13A | 108.5 |
C1—C2—H2 | 119.6 | C12—C13—H13A | 108.5 |
C3—C2—H2 | 119.6 | O8B—C13—H13B | 59.8 |
O2—C3—C2 | 124.45 (13) | O8A—C13—H13B | 108.5 |
O2—C3—C4 | 120.46 (13) | C12—C13—H13B | 108.5 |
C2—C3—C4 | 115.07 (12) | H13A—C13—H13B | 107.5 |
O3—C4—C5 | 120.03 (12) | O8B—C13—H13C | 108.9 |
O3—C4—C3 | 119.06 (12) | O8A—C13—H13C | 58.6 |
C5—C4—C3 | 120.89 (13) | C12—C13—H13C | 112.0 |
C4—C5—O1 | 120.60 (12) | H13A—C13—H13C | 53.5 |
C4—C5—C7 | 126.41 (13) | H13B—C13—H13C | 139.0 |
O1—C5—C7 | 112.99 (11) | O8B—C13—H13D | 104.3 |
O4A—C6—O4B | 109.7 (3) | O8A—C13—H13D | 133.4 |
O4A—C6—C1 | 111.96 (15) | C12—C13—H13D | 111.1 |
O4B—C6—C1 | 108.5 (2) | H13A—C13—H13D | 60.5 |
O4A—C6—H6A | 109.2 | H13B—C13—H13D | 48.6 |
C1—C6—H6A | 109.2 | H13C—C13—H13D | 108.8 |
O4A—C6—H6B | 109.2 | C15—C14—C7 | 113.65 (12) |
O4B—C6—H6B | 108.1 | C15—C14—H14A | 108.8 |
C1—C6—H6B | 109.2 | C7—C14—H14A | 108.8 |
H6A—C6—H6B | 107.9 | C15—C14—H14B | 108.8 |
O4A—C6—H6C | 109.0 | C7—C14—H14B | 108.8 |
O4B—C6—H6C | 107.4 | H14A—C14—H14B | 107.7 |
C1—C6—H6C | 110.2 | C14—C15—C16 | 112.37 (14) |
H6A—C6—H6C | 107.1 | C14—C15—H15A | 109.1 |
O4B—C6—H6D | 112.6 | C16—C15—H15A | 109.1 |
C1—C6—H6D | 109.6 | C14—C15—H15B | 109.1 |
H6A—C6—H6D | 112.1 | C16—C15—H15B | 109.1 |
H6B—C6—H6D | 108.8 | H15A—C15—H15B | 107.9 |
H6C—C6—H6D | 108.6 | C17—C16—C15 | 113.87 (17) |
C5—C7—C8 | 111.20 (12) | C17—C16—H16A | 108.8 |
C5—C7—C14 | 112.71 (12) | C15—C16—H16A | 108.8 |
C8—C7—C14 | 110.77 (11) | C17—C16—H16B | 108.8 |
C5—C7—H7 | 107.3 | C15—C16—H16B | 108.8 |
C8—C7—H7 | 107.3 | H16A—C16—H16B | 107.7 |
C14—C7—H7 | 107.3 | C16—C17—H17A | 109.5 |
C9—C8—O7 | 120.75 (13) | C16—C17—H17B | 109.5 |
C9—C8—C7 | 126.05 (13) | H17A—C17—H17B | 109.5 |
O7—C8—C7 | 113.13 (12) | C16—C17—H17C | 109.5 |
C8—C9—O5 | 119.76 (13) | H17A—C17—H17C | 109.5 |
C8—C9—C10 | 120.76 (14) | H17B—C17—H17C | 109.5 |
O5—C9—C10 | 119.48 (13) | ||
C5—O1—C1—C2 | −0.8 (2) | C5—C7—C8—C9 | 118.54 (16) |
C5—O1—C1—C6 | 176.06 (12) | C14—C7—C8—C9 | −115.30 (16) |
O1—C1—C2—C3 | 0.4 (2) | C5—C7—C8—O7 | −64.36 (15) |
C6—C1—C2—C3 | −175.94 (14) | C14—C7—C8—O7 | 61.80 (15) |
C1—C2—C3—O2 | 177.73 (16) | O7—C8—C9—O5 | 179.93 (13) |
C1—C2—C3—C4 | −0.6 (2) | C7—C8—C9—O5 | −3.2 (2) |
O2—C3—C4—O3 | 1.3 (2) | O7—C8—C9—C10 | 0.1 (2) |
C2—C3—C4—O3 | 179.63 (13) | C7—C8—C9—C10 | 176.96 (13) |
O2—C3—C4—C5 | −177.25 (14) | C8—C9—C10—O6 | 179.85 (15) |
C2—C3—C4—C5 | 1.1 (2) | O5—C9—C10—O6 | 0.0 (2) |
O3—C4—C5—O1 | 179.94 (13) | C8—C9—C10—C11 | 0.5 (2) |
C3—C4—C5—O1 | −1.5 (2) | O5—C9—C10—C11 | −179.41 (14) |
O3—C4—C5—C7 | 0.1 (2) | O6—C10—C11—C12 | −179.32 (16) |
C3—C4—C5—C7 | 178.57 (13) | C9—C10—C11—C12 | 0.0 (2) |
C1—O1—C5—C4 | 1.4 (2) | C10—C11—C12—O7 | −1.1 (2) |
C1—O1—C5—C7 | −178.71 (12) | C10—C11—C12—C13 | 176.58 (17) |
C2—C1—C6—O4A | −20.6 (2) | C8—O7—C12—C11 | 1.7 (2) |
O1—C1—C6—O4A | 162.71 (14) | C8—O7—C12—C13 | −176.37 (14) |
C2—C1—C6—O4B | 100.7 (3) | C11—C12—C13—O8B | −29.2 (7) |
O1—C1—C6—O4B | −76.1 (3) | O7—C12—C13—O8B | 148.7 (7) |
C4—C5—C7—C8 | −111.66 (16) | C11—C12—C13—O8A | 28.5 (3) |
O1—C5—C7—C8 | 68.45 (15) | O7—C12—C13—O8A | −153.56 (17) |
C4—C5—C7—C14 | 123.26 (16) | C5—C7—C14—C15 | −61.92 (17) |
O1—C5—C7—C14 | −56.62 (16) | C8—C7—C14—C15 | 172.77 (13) |
C12—O7—C8—C9 | −1.1 (2) | C7—C14—C15—C16 | −177.67 (14) |
C12—O7—C8—C7 | −178.40 (12) | C14—C15—C16—C17 | 178.09 (18) |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3···O2i | 0.82 | 1.96 | 2.7275 (15) | 155 |
O3—H3···O2 | 0.82 | 2.32 | 2.7440 (15) | 113 |
O5—H5···O6ii | 0.82 | 2.00 | 2.7488 (16) | 151 |
O5—H5···O6 | 0.82 | 2.32 | 2.7436 (16) | 113 |
O4A—H4A···O2iii | 0.82 | 2.07 | 2.839 (2) | 157 |
O8A—H8A···O6iii | 0.82 | 2.15 | 2.894 (2) | 152 |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x, −y+1, −z; (iii) x+1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C17H20O8 |
Mr | 352.33 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 296 |
a, b, c (Å) | 6.4234 (3), 9.2394 (4), 15.8494 (7) |
α, β, γ (°) | 79.993 (1), 86.689 (2), 66.622 (1) |
V (Å3) | 850.22 (7) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.49 × 0.47 × 0.33 |
Data collection | |
Diffractometer | Rigaku R-AXIS RAPID/ZJUG |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.938, 0.965 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8442, 3840, 2907 |
Rint | 0.017 |
(sin θ/λ)max (Å−1) | 0.648 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.043, 0.120, 1.00 |
No. of reflections | 3840 |
No. of parameters | 251 |
No. of restraints | 6 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.30, −0.30 |
Computer programs: PROCESS-AUTO (Rigaku, 2006), CrystalStructure (Rigaku, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia,1997), WinGX (Farrugia, 1999).
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3···O2i | 0.82 | 1.96 | 2.7275 (15) | 155 |
O3—H3···O2 | 0.82 | 2.32 | 2.7440 (15) | 113 |
O5—H5···O6ii | 0.82 | 2.00 | 2.7488 (16) | 151 |
O5—H5···O6 | 0.82 | 2.32 | 2.7436 (16) | 113 |
O4A—H4A···O2iii | 0.82 | 2.07 | 2.839 (2) | 157 |
O8A—H8A···O6iii | 0.82 | 2.15 | 2.894 (2) | 152 |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x, −y+1, −z; (iii) x+1, y, z. |
Acknowledgements
The work was supported financially by the National Natural Science Foundation of China (grant No. 20972138) and the Qianjiang Scholars Fund, Zhejiang Province (grant No. 2010R10051).
References
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Kojic acid possesses appreciable inhibitory activity against tyrosinase, a key enzyme in the biosynthesis of melanin, due to its ability to chelate copper in the active site of this enzyme. Thus kojic acid inhibits the production of melanin pigment, consequently being used in cosmetic. Therefore, in an attempt to seek potent tyrosinase inhibitors, the derivatives of kojic acid have been widely investigated (Kobayashi et al., 1995).There were little attentation to crystal structure of kojic and derivatives.The similar crystal structure of Kojic acid have been reported on 5-hydroxy-2-(hydroxymenthyl) -4H-pyran-one (Lokaj et al., 1991; Kakkar et al., 2011) and 6,6'-methylenebis (5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one) (Nurchi et al., 2010). Herein, we report the crystal structure of the title compound (I).
In (I) (Fig. 1), two pyranone rings are planar forming the dihedral angle of 61.2 (2)°. Hydroxyl groups are almost coplanar with their linked pyranone rings forming the torsion angles O2—C3—C4—O3 of -0.10° and O6—C10—C9—O5 of 1.24°.
Intermolecular hydrogen bonds O3—H3···O2i and O5—H5···O6ii (Table 1) link molecules into zigzag chains along the c axis. Further, intermolecular hydrogen bonds O4A—H4···O2iii and O8A—H8A···O6iii (Table 1) link all of the components of the structure into layers parallel to ac plane.