(3aRS,7aRS)-3a-Hydr­oxy-3,3a,7,7a-tetra­hydro­benzofuran-2,6-dione

Single crystals of senecio lactone, C₈H₈O₄, isolated from Senecio scandens Buch–Ham, were obtained from an acetone solution. In the crystal structure, mol­ecules are linked to each other by inter­molecular O—H...O hydrogen bonds involving a ketone group and the hydroxyl group.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.055
• wR factor = 0.147
• Data-to-parameter ratio = 13.9

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT021_ALERT_1_B Ratio Unique / Expected Reflections too High ...       1.19
PLAT029_ALERT_3_B _diffrn_measured_fraction_theta_full Low .......       0.95
PLAT432_ALERT_2_B Short Inter X...Y Contact  O2     ..  C6      ..       2.91 Ang.

Alert level C
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          1
              C8 H8 O4

   0 ALERT level A = In general: serious problem
   3 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: DENZO (Otwinowski & Minor, 1997); cell refinement: SCALE (Otwinowski & Minor, 1997); data reduction: SCALE; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976) and PLUTON (Spek, 2003); software used to prepare material for publication: SHELXL97.

(3aRS,7aRS)-3a-Hydroxy-3,3a,7,7a-tetrahydrobenzofuran-2,6-dione

Crystal data

C8H8O4	Dx = 1.524 Mg m^−3
Mr = 168.15	Melting point = 382–384 K
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 6.7870 (14) Å	Cell parameters from 2341 reflections
b = 10.711 (2) Å	θ = 2.8–25.0°
c = 10.311 (2) Å	µ = 0.12 mm^−1
β = 102.06 (3)°	T = 295 K
V = 733.0 (3) Å^3	Plate, colourless
Z = 4	0.50 × 0.40 × 0.10 mm
F(000) = 352

Data collection

MAC DIP-2030K diffractometer	1533 reflections with I > 2σ(I)
Radiation source: rotating-anode	Rint = 0.032
Graphite monochromator	θmax = 25.0°, θmin = 2.8°
ω scans	h = 0→8
2341 measured reflections	k = −12→13
1534 independent reflections	l = −13→12

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.055	H-atom parameters constrained
wR(F^2) = 0.147	w = 1/[σ^2(Fo^2) + (0.0589P)^2 + 0.3161P] where P = (Fo^2 + 2Fc^2)/3
S = 1.27	(Δ/σ)max < 0.001
1534 reflections	Δρmax = 0.24 e Å^−3
110 parameters	Δρmin = −0.18 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.122 (15)

Special details

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.

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

	x	y	z	Uiso*/Ueq
O1	−0.1607 (2)	−0.06981 (15)	−0.60570 (15)	0.0488 (4)
O2	−0.4950 (2)	−0.08404 (16)	−0.63864 (16)	0.0562 (5)
O3	−0.1067 (2)	−0.32862 (14)	−0.67556 (16)	0.0498 (4)
H3A	0.0040	−0.3626	−0.6585	0.075*
O4	0.2691 (2)	0.02618 (16)	−0.90892 (16)	0.0546 (5)
C1	−0.3425 (3)	−0.10692 (19)	−0.6760 (2)	0.0424 (5)
C2	−0.3156 (3)	−0.17683 (19)	−0.7978 (2)	0.0415 (5)
H2A	−0.4086	−0.2464	−0.8170	0.050*
H2B	−0.3336	−0.1224	−0.8746	0.050*
C3	−0.0981 (3)	−0.22170 (17)	−0.75689 (19)	0.0378 (5)
C4	0.0063 (3)	−0.2518 (2)	−0.8676 (2)	0.0421 (5)
H4A	−0.0161	−0.3297	−0.9078	0.051*
C5	0.1292 (3)	−0.17322 (19)	−0.9117 (2)	0.0433 (5)
H5A	0.1945	−0.1999	−0.9776	0.052*
C6	0.1652 (3)	−0.04606 (19)	−0.8599 (2)	0.0421 (5)
C7	0.0591 (3)	−0.00511 (19)	−0.7529 (2)	0.0446 (5)
H7A	0.1470	0.0511	−0.6935	0.054*
H7B	−0.0605	0.0414	−0.7935	0.054*
C8	−0.0026 (3)	−0.1112 (2)	−0.6716 (2)	0.0412 (5)
H8A	0.1143	−0.1398	−0.6056	0.049*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0446 (8)	0.0609 (9)	0.0429 (8)	0.0028 (7)	0.0139 (6)	−0.0098 (7)
O2	0.0484 (9)	0.0675 (11)	0.0580 (10)	0.0130 (7)	0.0235 (7)	0.0091 (8)
O3	0.0492 (8)	0.0429 (8)	0.0612 (9)	0.0076 (6)	0.0205 (7)	0.0153 (7)
O4	0.0534 (9)	0.0562 (9)	0.0545 (9)	−0.0137 (7)	0.0122 (7)	0.0086 (7)
C1	0.0422 (10)	0.0444 (10)	0.0425 (10)	0.0056 (8)	0.0135 (8)	0.0079 (8)
C2	0.0379 (9)	0.0436 (10)	0.0432 (10)	−0.0004 (8)	0.0091 (8)	0.0017 (8)
C3	0.0385 (9)	0.0354 (9)	0.0409 (9)	0.0004 (7)	0.0116 (7)	0.0032 (7)
C4	0.0439 (10)	0.0395 (9)	0.0444 (10)	0.0013 (8)	0.0129 (8)	−0.0035 (8)
C5	0.0434 (10)	0.0466 (11)	0.0432 (10)	0.0024 (8)	0.0161 (8)	−0.0013 (8)
C6	0.0368 (9)	0.0435 (10)	0.0444 (10)	−0.0009 (8)	0.0051 (8)	0.0057 (8)
C7	0.0424 (10)	0.0388 (10)	0.0529 (11)	−0.0021 (8)	0.0108 (9)	−0.0058 (9)
C8	0.0365 (9)	0.0477 (11)	0.0395 (9)	0.0038 (8)	0.0083 (7)	−0.0034 (8)

Geometric parameters (Å, º)

O1—C1	1.354 (3)	C3—C8	1.535 (3)
O1—C8	1.454 (2)	C4—C5	1.330 (3)
O2—C1	1.203 (2)	C4—H4A	0.9300
O3—C3	1.428 (2)	C5—C6	1.465 (3)
O3—H3A	0.8200	C5—H5A	0.9300
O4—C6	1.225 (2)	C6—C7	1.503 (3)
C1—C2	1.506 (3)	C7—C8	1.522 (3)
C2—C3	1.526 (3)	C7—H7A	0.9700
C2—H2A	0.9700	C7—H7B	0.9700
C2—H2B	0.9700	C8—H8A	0.9800
C3—C4	1.500 (3)
C1—O1—C8	109.83 (15)	C3—C4—H4A	118.2
C3—O3—H3A	109.5	C4—C5—C6	122.18 (18)
O2—C1—O1	121.2 (2)	C4—C5—H5A	118.9
O2—C1—C2	129.1 (2)	C6—C5—H5A	118.9
O1—C1—C2	109.70 (16)	O4—C6—C5	120.22 (19)
C1—C2—C3	101.82 (16)	O4—C6—C7	121.59 (19)
C1—C2—H2A	111.4	C5—C6—C7	118.04 (17)
C3—C2—H2A	111.4	C6—C7—C8	114.55 (17)
C1—C2—H2B	111.4	C6—C7—H7A	108.6
C3—C2—H2B	111.4	C8—C7—H7A	108.6
H2A—C2—H2B	109.3	C6—C7—H7B	108.6
O3—C3—C4	111.02 (15)	C8—C7—H7B	108.6
O3—C3—C2	105.02 (15)	H7A—C7—H7B	107.6
C4—C3—C2	116.16 (17)	O1—C8—C7	110.18 (17)
O3—C3—C8	110.27 (16)	O1—C8—C3	103.77 (15)
C4—C3—C8	113.06 (16)	C7—C8—C3	113.09 (17)
C2—C3—C8	100.60 (15)	O1—C8—H8A	109.9
C5—C4—C3	123.65 (19)	C7—C8—H8A	109.9
C5—C4—H4A	118.2	C3—C8—H8A	109.9
C8—O1—C1—O2	179.06 (19)	O4—C6—C7—C8	−160.35 (19)
C8—O1—C1—C2	−0.4 (2)	C5—C6—C7—C8	24.1 (3)
O2—C1—C2—C3	−156.0 (2)	C1—O1—C8—C7	98.59 (19)
O1—C1—C2—C3	23.4 (2)	C1—O1—C8—C3	−22.8 (2)
C1—C2—C3—O3	79.57 (18)	C6—C7—C8—O1	−159.93 (16)
C1—C2—C3—C4	−157.36 (16)	C6—C7—C8—C3	−44.3 (2)
C1—C2—C3—C8	−34.95 (18)	O3—C3—C8—O1	−74.90 (18)
O3—C3—C4—C5	−142.3 (2)	C4—C3—C8—O1	160.15 (16)
C2—C3—C4—C5	97.8 (2)	C2—C3—C8—O1	35.60 (18)
C8—C3—C4—C5	−17.8 (3)	O3—C3—C8—C7	165.73 (15)
C3—C4—C5—C6	−3.4 (3)	C4—C3—C8—C7	40.8 (2)
C4—C5—C6—O4	−175.3 (2)	C2—C3—C8—C7	−83.77 (19)
C4—C5—C6—C7	0.3 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3A···O4^i	0.82	1.96	2.756 (2)	165

Symmetry code: (i) −x+1/2, y−1/2, −z−3/2.