3,3′-Dihy­droxy-6,6′-bis­(hy­droxy­meth­yl)-2,2′-(pentane-1,1-di­yl)di-4H-pyran-4-one

Mu-Song Liu; Pan-Pan Hu; Tao Zhou

doi:10.1107/S1600536812010276

. 2012 Mar 14;68(Pt 4):o1064. doi: 10.1107/S1600536812010276

3,3′-Dihydroxy-6,6′-bis(hydroxymethyl)-2,2′-(pentane-1,1-diyl)di-4H-pyran-4-one

Mu-Song Liu ^a, Pan-Pan Hu ^b, Tao Zhou ^b,^*

PMCID: PMC3344022 PMID: 22589931

Abstract

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

C₁₇H₂₀O₈
M _r = 352.33
Triclinic,
a = 6.4234 (3) Å
b = 9.2394 (4) Å
c = 15.8494 (7) Å
α = 79.993 (1)°
β = 86.689 (2)°
γ = 66.622 (1)°
V = 850.22 (7) Å³
Z = 2
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 296 K
0.49 × 0.47 × 0.33 mm

Data collection

Rigaku R-AXIS RAPID/ZJUG diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.938, T _max = 0.965
8442 measured reflections
3840 independent reflections
2907 reflections with I > 2σ(I)
R _int = 0.017

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.120
S = 1.00
3840 reflections
251 parameters
6 restraints
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Data collection: PROCESS-AUTO (Rigaku, 2006 ▶); cell refinement: 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 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812010276/cv5255sup1.cif

e-68-o1064-sup1.cif^{(28.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812010276/cv5255Isup2.hkl

e-68-o1064-Isup2.hkl^{(184.4KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812010276/cv5255Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

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

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

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).

supplementary crystallographic information

Comment

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.

Experimental

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).