6,8-Dihydr­oxy-3-methyl­isocoumarin

Abstract

The title compound, C₁₀H₈O₄, was isolated from the fermentation culture of the endophytic fungus Cephalo­sporium sp. In the crystal structure, mol­ecules are connected into a one-dimensional chain along [101] by inter­molecular O—H⋯O hydrogen bonds involving the hydroxyl and carbonyl functionalities. The chains are linked by non-classical C—H⋯O inter­actions, forming extended two-dimensional layers approximately parallel to (11).

Related literature

For new bioactive secondary metabolites from marine fungi, see: Shao et al. (2007 ▶). For the investigation of an endophytic strain Cephalosporium sp., see: Wei et al. (2008 ▶); Hemingway et al. (1977 ▶); Kendall et al. (1989 ▶). For crystal structures with non-classical C—H⋯O inter­actions, see: Nangia (2002 ▶).

Experimental

Crystal data

• C₁₀H₈O₄

• M _r = 192.16

• Monoclinic,

• a = 3.8201 (7) Å

• b = 15.710 (3) Å

• c = 14.196 (2) Å

• β = 92.668 (2)°

• V = 851.1 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.12 mm⁻¹

• T = 291 K

• 0.27 × 0.20 × 0.19 mm

Data collection

• Bruker APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.969, T _max = 0.978

• 4781 measured reflections

• 1586 independent reflections

• 1272 reflections with I > 2σ(I)

• R _int = 0.021

Refinement

• R[F ² > 2σ(F ²)] = 0.034

• wR(F ²) = 0.094

• S = 1.04

• 1586 reflections

• 131 parameters

• H-atom parameters constrained

• Δρ_max = 0.18 e Å⁻³

• Δρ_min = −0.14 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick 2008 ▶); molecular graphics: SHELXTL (Sheldrick 2008 ▶); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

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
O4—H4⋯O2i	0.82	1.96	2.7225 (15)	155
C5—H5⋯O4ii	0.93	2.60	3.4659 (19)	155

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

Endophytic fungi have proven to be a rich source of novel structural compounds with interesting biological activities and a high level of biodiversity. In the course of our search for new or bioactive secondary metabolites from the marine fungi (Shao et al., 2007). we have investigated an endophytic strain Cephalosporium sp. (Wei et al., 2008). The title compound was previously isolated from the organic extracts of the fungus Ceratocystis minor (Hemingway et al., 1977), and elucidated on the basic of spectroscopic analysis (Kendall et al., 1989). Herein, the title compound was isolated from the fermentation culture of the endophytic fungus Cephalosporium sp., and its crystal structure is reported.

The asymmetric unit of the title compound contains one independent molecule (Fig. 1), in which the bond lengths and angles are within the expected ranges. The structural analysis reveals that the most relevant feature is the arrangement of the molecules, which are connected to form a one-dimensional chain along the [101] direction, by the formation of intermolecular O—H···O hydrogen bonds. Furthermore, weak non-conventional intermolecular C—H···O interactions are observed (Nangia, 2002), in which C5—H5 is a donor and O4 is an acceptor. These interactions consolidate the crystal packing. Details of hydrogen bonds are given in Table 1.

Experimental

A strain of fungus Cephalosporium sp. (No. 2090) was deposited in the School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, People's Republic of China. Culture conditions: GYT medium (glucose 10 g/L, peptone 2 g/L, yeast extract 1 g/L, NaCl 2.5 g/L) and incubation at 298 K for 4 weeks. The cultures (70 L) were filtered through cheesecloth. The filtrate was concentrated to 3 L below 323 K, extracted five times by shaking with an equal volume of ethyl acetate. The extract was evaporated under reduced pressure below 323 K. The combined organic extracts were chromatographed on silica-gel, eluting with petroleum ether/ethyl acetate, to yield the title compound. Crystals were obtained by evaporation of an ethyl acetate solution.

Refinement

All H atoms were positioned geometrically and treated as riding, with C—H bond lengths constrained to 0.93 (aromatic CH), 0.96 (methyl CH₃), and 0.82 Å (hydroxyl OH), and with U_iso(H) = 1.5Ueq(carrier atom) or for CH₃ and OH groups and U_iso(H) = 1.2Ueq(carrier C) otherwise.

Figures

Fig. 1.

View of the title molecule with atom numbering scheme and 30% probability displacement ellipsoids for non-hydrogen atoms.

Fig. 2.

View of the 2D layers formed by intermolecular O—H···O hydrogen bonds and weak non-conventional intermolecular C—H···O interactions.

Crystal data

C10H8O4	F(000) = 400
Mr = 192.16	Dx = 1.500 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1738 reflections
a = 3.8201 (7) Å	θ = 2.6–25.5°
b = 15.710 (3) Å	µ = 0.12 mm−1
c = 14.196 (2) Å	T = 291 K
β = 92.668 (2)°	Block, yellow
V = 851.1 (3) Å3	0.27 × 0.20 × 0.19 mm
Z = 4

Data collection

Bruker APEXII CCD diffractometer	1586 independent reflections
Radiation source: fine-focus sealed tube	1272 reflections with I > 2σ(I)
graphite	Rint = 0.021
φ and ω scans	θmax = 25.5°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −4→4
Tmin = 0.969, Tmax = 0.978	k = −19→13
4781 measured reflections	l = −17→17

Refinement

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)] = 0.034	H-atom parameters constrained
wR(F2) = 0.094	w = 1/[σ2(Fo2) + (0.0441P)2 + 0.1957P] where P = (Fo2 + 2Fc2)/3
S = 1.04	(Δ/σ)max < 0.001
1586 reflections	Δρmax = 0.18 e Å−3
131 parameters	Δρmin = −0.14 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 constraints	Extinction coefficient: 0.015 (3)
Primary atom site location: structure-invariant direct methods

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.3482 (3)	0.32453 (7)	0.81217 (7)	0.0451 (3)
O2	0.3544 (3)	0.19366 (7)	0.75748 (8)	0.0572 (4)
O3	0.0718 (3)	0.15766 (7)	0.58873 (8)	0.0552 (4)
H3	0.1709	0.1476	0.6400	0.083*
O4	−0.4021 (3)	0.39231 (7)	0.41364 (7)	0.0487 (3)
H4	−0.4514	0.3541	0.3759	0.073*
C1	0.3853 (4)	0.45742 (12)	0.89102 (11)	0.0516 (4)
H1A	0.3148	0.5160	0.8859	0.077*
H1B	0.6359	0.4542	0.8987	0.077*
H1C	0.2819	0.4321	0.9446	0.077*
C2	0.2659 (4)	0.41080 (10)	0.80372 (10)	0.0395 (4)
C3	0.1028 (4)	0.44079 (10)	0.72629 (10)	0.0379 (4)
H3A	0.0505	0.4985	0.7224	0.046*
C4	0.0042 (3)	0.38590 (9)	0.64774 (9)	0.0318 (3)
C5	−0.1641 (4)	0.41528 (9)	0.56587 (10)	0.0355 (3)
H5	−0.2230	0.4725	0.5598	0.043*
C6	−0.2453 (4)	0.35866 (10)	0.49244 (10)	0.0354 (3)
C7	−0.1659 (4)	0.27235 (9)	0.50066 (10)	0.0378 (4)
H7	−0.2235	0.2354	0.4512	0.045*
C8	−0.0016 (4)	0.24192 (9)	0.58233 (10)	0.0368 (3)
C9	0.0880 (4)	0.29837 (9)	0.65755 (9)	0.0337 (3)
C10	0.2651 (4)	0.26818 (10)	0.74166 (10)	0.0401 (4)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0531 (7)	0.0503 (7)	0.0308 (5)	0.0018 (5)	−0.0102 (5)	−0.0008 (5)
O2	0.0802 (9)	0.0448 (7)	0.0447 (7)	0.0086 (6)	−0.0182 (6)	0.0060 (5)
O3	0.0804 (9)	0.0330 (6)	0.0503 (7)	0.0065 (5)	−0.0162 (6)	−0.0011 (5)
O4	0.0677 (8)	0.0425 (6)	0.0342 (6)	0.0033 (5)	−0.0174 (5)	−0.0004 (5)
C1	0.0488 (10)	0.0661 (11)	0.0390 (9)	−0.0024 (8)	−0.0060 (7)	−0.0131 (8)
C2	0.0382 (8)	0.0459 (9)	0.0344 (8)	−0.0026 (7)	0.0008 (6)	−0.0058 (6)
C3	0.0414 (8)	0.0372 (8)	0.0350 (8)	−0.0021 (6)	0.0002 (6)	−0.0034 (6)
C4	0.0311 (7)	0.0354 (8)	0.0291 (7)	−0.0033 (6)	0.0016 (6)	−0.0006 (6)
C5	0.0405 (8)	0.0314 (8)	0.0344 (7)	0.0001 (6)	−0.0011 (6)	0.0009 (6)
C6	0.0354 (8)	0.0407 (8)	0.0297 (7)	−0.0013 (6)	−0.0037 (6)	0.0029 (6)
C7	0.0437 (8)	0.0379 (9)	0.0312 (7)	−0.0045 (6)	−0.0047 (6)	−0.0053 (6)
C8	0.0412 (8)	0.0318 (8)	0.0370 (8)	−0.0010 (6)	−0.0011 (6)	−0.0003 (6)
C9	0.0344 (8)	0.0364 (8)	0.0301 (7)	−0.0011 (6)	−0.0005 (6)	0.0019 (6)
C10	0.0436 (9)	0.0422 (9)	0.0339 (8)	0.0007 (7)	−0.0030 (6)	0.0033 (6)

Geometric parameters (Å, °)

O1—C10	1.3626 (18)	C3—C4	1.4457 (19)
O1—C2	1.3951 (19)	C3—H3A	0.9300
O2—C10	1.2370 (18)	C4—C5	1.3813 (19)
O3—C8	1.3553 (18)	C4—C9	1.417 (2)
O3—H3	0.8200	C5—C6	1.394 (2)
O4—C6	1.3518 (17)	C5—H5	0.9300
O4—H4	0.8200	C6—C7	1.393 (2)
C1—C2	1.493 (2)	C7—C8	1.378 (2)
C1—H1A	0.9600	C7—H7	0.9300
C1—H1B	0.9600	C8—C9	1.418 (2)
C1—H1C	0.9600	C9—C10	1.426 (2)
C2—C3	1.325 (2)
C10—O1—C2	121.61 (11)	C4—C5—C6	119.64 (13)
C8—O3—H3	109.5	C4—C5—H5	120.2
C6—O4—H4	109.5	C6—C5—H5	120.2
C2—C1—H1A	109.5	O4—C6—C7	122.43 (13)
C2—C1—H1B	109.5	O4—C6—C5	116.35 (13)
H1A—C1—H1B	109.5	C7—C6—C5	121.22 (13)
C2—C1—H1C	109.5	C8—C7—C6	119.81 (13)
H1A—C1—H1C	109.5	C8—C7—H7	120.1
H1B—C1—H1C	109.5	C6—C7—H7	120.1
C3—C2—O1	120.81 (13)	O3—C8—C7	118.69 (13)
C3—C2—C1	128.92 (15)	O3—C8—C9	121.23 (13)
O1—C2—C1	110.27 (13)	C7—C8—C9	120.08 (13)
C2—C3—C4	121.57 (14)	C4—C9—C8	119.18 (12)
C2—C3—H3A	119.2	C4—C9—C10	120.08 (13)
C4—C3—H3A	119.2	C8—C9—C10	120.74 (13)
C5—C4—C9	120.07 (12)	O2—C10—O1	115.39 (13)
C5—C4—C3	122.96 (13)	O2—C10—C9	125.66 (14)
C9—C4—C3	116.96 (12)	O1—C10—C9	118.96 (13)
C10—O1—C2—C3	0.1 (2)	C5—C4—C9—C8	0.3 (2)
C10—O1—C2—C1	179.78 (13)	C3—C4—C9—C8	−179.69 (13)
O1—C2—C3—C4	−0.1 (2)	C5—C4—C9—C10	179.32 (13)
C1—C2—C3—C4	−179.74 (14)	C3—C4—C9—C10	−0.66 (19)
C2—C3—C4—C5	−179.60 (14)	O3—C8—C9—C4	−179.69 (13)
C2—C3—C4—C9	0.4 (2)	C7—C8—C9—C4	0.5 (2)
C9—C4—C5—C6	−1.1 (2)	O3—C8—C9—C10	1.3 (2)
C3—C4—C5—C6	178.85 (13)	C7—C8—C9—C10	−178.57 (13)
C4—C5—C6—O4	−178.42 (12)	C2—O1—C10—O2	179.49 (13)
C4—C5—C6—C7	1.3 (2)	C2—O1—C10—C9	−0.4 (2)
O4—C6—C7—C8	179.14 (14)	C4—C9—C10—O2	−179.17 (15)
C5—C6—C7—C8	−0.5 (2)	C8—C9—C10—O2	−0.2 (2)
C6—C7—C8—O3	179.79 (14)	C4—C9—C10—O1	0.7 (2)
C6—C7—C8—C9	−0.3 (2)	C8—C9—C10—O1	179.67 (13)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2	0.82	1.92	2.6426 (16)	146
O4—H4···O2i	0.82	1.96	2.7225 (15)	155
C5—H5···O4ii	0.93	2.60	3.4659 (19)	155

Symmetry codes: (i) x−1, −y+1/2, z−1/2; (ii) −x−1, −y+1, −z+1.