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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 68| Part 7| July 2012| Page o2108
https://doi.org/10.1107/S1600536812026475

2-[(2-Acet­­oxy­benzo­yl)­­oxy]benzoic acid

Katarzyna A. Solankoa and Andrew D. Bonda*

aUniversity of Southern Denmark, Department of Physics, Chemistry and Pharmacy, Campusvej 55, 5230 Odense, Denmark
*Correspondence e-mail: adb@chem.sdu.dk

(Received 7 May 2012; accepted 11 June 2012; online 16 June 2012)

The title compound, C16H12O6, is a common impurity of ortho-acetyl­salicylic acid (aspirin). The benzene rings form a dihedral angle of 81.9 (1)° while the acetyl and carboxyl groups form dihedral angles of 74.0 (1) and 26.4 (2)°, respectively, with the benzene rings to which they are bound. In the crystal, mol­ecules are linked by pairs of O—H⋯O hydrogen bonds between the carboxyl groups, forming inversion dimers.

Related literature

For background literature concerning the crystallization and crystal structure of aspirin, see: Bond et al. (2007[Bond, A. D., Boese, R. & Desiraju, G. R. (2007). Angew. Chem. Int. Ed. 46, 618-622.], 2011[Bond, A. D., Solanko, K. A., Parsons, S., Redder, S. & Boese, R. (2011). CrystEngComm, 13, 399-401.]). For a discussion of the pharmacological effects of acetyl­salicyl­salicylic acid, see: Bundgaard (1974[Bundgaard, H. (1974). J. Pharm. Pharmacol. 26, 18-22.]). For related structures, see: Greener et al. (2000[Greener, B., Archibald, S. J. & Hodkinson, M. (2000). Angew. Chem. Int. Ed. 39, 3601-3604.]); Cox et al. (2000[Cox, P. J., Gilmour, G. I. & MacManus, S. M. (2000). Int. J. Pharm. 204, 133-136.]); Iqbal et al. (2007[Iqbal, R., Zareef, M., Aziz, S., Qadeer, G. & Arfan, M. (2007). Acta Cryst. E63, o744-o745.]).

[Scheme 1]

Experimental

Crystal data

  • C16H12O6

  • Mr = 300.26

  • Monoclinic, P 21 /c

  • a = 9.6314 (5) Å

  • b = 7.7548 (3) Å

  • c = 18.0763 (8) Å

  • β = 95.572 (2)°

  • V = 1343.73 (11) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.12 mm−1

  • T = 150 K

  • 0.40 × 0.20 × 0.02 mm
Data collection

  • Bruker Nonius X8 APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.887, Tmax = 0.998

  • 15807 measured reflections

  • 2367 independent reflections

  • 1868 reflections with I > 2σ(I)

  • Rint = 0.031
Refinement

  • R[F2 > 2σ(F2)] = 0.033

  • wR(F2) = 0.080

  • S = 1.04

  • 2367 reflections

  • 204 parameters

  • 1 restraint

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.18 e Å−3

  • Δρmin = −0.17 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O5—H5⋯O6i 0.86 (1) 1.81 (1) 2.6660 (16) 176 (2)
Symmetry code: (i) -x, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2010[Bruker (2010). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2010[Bruker (2010). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536812026475/fy2058sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812026475/fy2058Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S1600536812026475/fy2058Isup3.cml

checkCIF report


Comment top

Acetylsalicylsalicylic acid is a condensation (dehydration) product of acetylsalicylic acid (aspirin) and salicylic acid, and is a common impurity in commerical aspirin samples. Its pharmacological effects have been examined by Bundgaard (1974), and it has been suggested that the compound is a potentially immunogenic substance involved in the development of allergic reactions to aspirin.

Related literature top

For background literature concerning the crystallization and crystal structure of aspirin, see: Bond et al. (2007, 2011). For a discussion of the pharmacological effects of acetylsalicylsalicylic acid, see: Bundgaard (1974). For related structures, see: Greener et al. (2000); Cox et al. (2000); Iqbal et al. (2007).

Experimental top

The compound was prepared by acetylation of salicylsalicylic acid (purchased from Alfa Aesar) using acetic anhydride. 0.02 mol of salicylsalicylic acid was mixed with 0.01 mol of acetic anhydride with addition of 10% NaOH (5 ml) and ca 50 ml ice. The reactants were stirred for ca 2 h and the reaction was monitored by thin-layer chromotography. When the reaction was complete, the white solid was filtered and recrystallized from ethanol (yield 90%).

Refinement top

H atoms bound to C atoms were placed geometrically and allowed to ride during refinement with C—H = 0.95 (aromatic) or 0.98 Å (methyl) and with Uiso(H) = 1.2 (aromatic) or 1.5Ueq(C) (methyl). The H atom bound to O5 was located in a difference Fourier map and refined with an isotropic displacement parameter, with the O—H distance restrained to 0.85 (1) Å.

Structure description top

Acetylsalicylsalicylic acid is a condensation (dehydration) product of acetylsalicylic acid (aspirin) and salicylic acid, and is a common impurity in commerical aspirin samples. Its pharmacological effects have been examined by Bundgaard (1974), and it has been suggested that the compound is a potentially immunogenic substance involved in the development of allergic reactions to aspirin.

For background literature concerning the crystallization and crystal structure of aspirin, see: Bond et al. (2007, 2011). For a discussion of the pharmacological effects of acetylsalicylsalicylic acid, see: Bundgaard (1974). For related structures, see: Greener et al. (2000); Cox et al. (2000); Iqbal et al. (2007).

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Molecular structure showing displacement ellipsoids at the 50% probability level for non-H atoms.
2-[(2-Acetoxybenzoyl)oxy]benzoic acid top
Crystal data top
C16H12O6F(000) = 624
Mr = 300.26Dx = 1.484 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 5582 reflections
a = 9.6314 (5) Åθ = 2.9–25.0°
b = 7.7548 (3) ŵ = 0.12 mm−1
c = 18.0763 (8) ÅT = 150 K
β = 95.572 (2)°Lath, colourless
V = 1343.73 (11) Å30.40 × 0.20 × 0.02 mm
Z = 4
Data collection top
Bruker Nonius X8 APEXII CCD
diffractometer		2367 independent reflections
Radiation source: fine-focus sealed tube1868 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.031
ω and φ scansθmax = 25.1°, θmin = 3.6°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)		h = −11→11
Tmin = 0.887, Tmax = 0.998k = −9→9
15807 measured reflectionsl = −21→20
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.033Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.080H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0341P)2 + 0.473P]
where P = (Fo2 + 2Fc2)/3
2367 reflections(Δ/σ)max < 0.001
204 parametersΔρmax = 0.18 e Å−3
1 restraintΔρmin = −0.17 e Å−3
Crystal data top
C16H12O6V = 1343.73 (11) Å3
Mr = 300.26Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.6314 (5) ŵ = 0.12 mm−1
b = 7.7548 (3) ÅT = 150 K
c = 18.0763 (8) Å0.40 × 0.20 × 0.02 mm
β = 95.572 (2)°
Data collection top
Bruker Nonius X8 APEXII CCD
diffractometer		2367 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)		1868 reflections with I > 2σ(I)
Tmin = 0.887, Tmax = 0.998Rint = 0.031
15807 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0331 restraint
wR(F2) = 0.080H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.18 e Å−3
2367 reflectionsΔρmin = −0.17 e Å−3
204 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
O10.25601 (10)0.66416 (13)0.32136 (5)0.0262 (3)
O20.38752 (12)0.75630 (15)0.42277 (7)0.0369 (3)
O30.62427 (10)0.57401 (13)0.46447 (5)0.0245 (3)
O40.69302 (12)0.76366 (15)0.38150 (6)0.0367 (3)
O50.07707 (13)0.52229 (15)0.41146 (6)0.0373 (3)
H50.052 (3)0.451 (3)0.4443 (11)0.082 (8)*
O60.00116 (13)0.70903 (14)0.49167 (6)0.0351 (3)
C10.45005 (15)0.49405 (19)0.36384 (8)0.0212 (3)
C20.40413 (16)0.3714 (2)0.31037 (8)0.0249 (4)
H2A0.32060.39140.27910.030*
C30.47842 (16)0.2217 (2)0.30243 (9)0.0281 (4)
H3A0.44610.13980.26560.034*
C40.59942 (17)0.1906 (2)0.34767 (9)0.0296 (4)
H4A0.64940.08630.34260.036*
C50.64823 (16)0.3111 (2)0.40048 (8)0.0263 (4)
H5A0.73200.29030.43140.032*
C60.57436 (15)0.46175 (19)0.40792 (8)0.0213 (3)
C70.36674 (15)0.6510 (2)0.37434 (8)0.0232 (4)
C80.67024 (15)0.7322 (2)0.44426 (9)0.0266 (4)
C90.68674 (17)0.8504 (2)0.50933 (9)0.0331 (4)
H9A0.73160.95740.49530.050*
H9B0.74470.79490.55010.050*
H9C0.59480.87680.52540.050*
C100.17065 (15)0.8088 (2)0.32687 (8)0.0236 (4)
C110.18395 (16)0.9407 (2)0.27723 (9)0.0283 (4)
H11A0.24970.93190.24150.034*
C120.10136 (16)1.0862 (2)0.27940 (9)0.0305 (4)
H12A0.10911.17650.24450.037*
C130.00762 (16)1.1002 (2)0.33224 (9)0.0303 (4)
H13A−0.04801.20090.33430.036*
C14−0.00502 (16)0.9675 (2)0.38195 (9)0.0273 (4)
H14A−0.06910.97840.41850.033*
C150.07431 (15)0.81807 (19)0.37966 (8)0.0234 (3)
C160.04899 (16)0.6788 (2)0.43270 (9)0.0258 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0273 (6)0.0265 (6)0.0240 (6)0.0042 (5)−0.0015 (5)−0.0055 (5)
O20.0365 (7)0.0319 (7)0.0394 (7)0.0092 (5)−0.0106 (5)−0.0158 (6)
O30.0298 (6)0.0216 (6)0.0218 (5)−0.0006 (5)0.0007 (4)−0.0024 (5)
O40.0456 (7)0.0353 (7)0.0296 (7)−0.0121 (6)0.0064 (5)0.0006 (5)
O50.0572 (8)0.0227 (7)0.0343 (7)0.0042 (6)0.0154 (6)0.0015 (5)
O60.0490 (7)0.0281 (7)0.0299 (6)0.0074 (5)0.0123 (5)0.0022 (5)
C10.0256 (8)0.0192 (8)0.0196 (8)−0.0030 (6)0.0066 (6)0.0000 (6)
C20.0259 (8)0.0258 (9)0.0235 (8)−0.0048 (7)0.0047 (6)−0.0016 (7)
C30.0339 (9)0.0233 (9)0.0284 (9)−0.0048 (7)0.0097 (7)−0.0078 (7)
C40.0372 (9)0.0212 (9)0.0322 (9)0.0034 (7)0.0125 (8)−0.0008 (7)
C50.0297 (8)0.0254 (9)0.0246 (8)0.0025 (7)0.0056 (7)0.0011 (7)
C60.0269 (8)0.0203 (8)0.0175 (8)−0.0032 (6)0.0062 (6)−0.0006 (6)
C70.0230 (8)0.0235 (8)0.0233 (8)−0.0025 (6)0.0025 (7)−0.0007 (7)
C80.0227 (8)0.0262 (9)0.0303 (9)−0.0005 (7)0.0004 (7)−0.0002 (7)
C90.0333 (9)0.0316 (10)0.0341 (9)−0.0021 (7)0.0019 (7)−0.0074 (8)
C100.0221 (7)0.0239 (9)0.0235 (8)0.0008 (6)−0.0042 (6)−0.0055 (7)
C110.0274 (8)0.0316 (10)0.0253 (8)−0.0048 (7)−0.0001 (7)−0.0007 (7)
C120.0326 (9)0.0275 (9)0.0299 (9)−0.0044 (7)−0.0052 (7)0.0059 (7)
C130.0288 (9)0.0249 (9)0.0356 (10)0.0045 (7)−0.0044 (7)0.0019 (8)
C140.0232 (8)0.0287 (9)0.0293 (8)0.0022 (7)−0.0003 (7)−0.0015 (7)
C150.0231 (8)0.0234 (8)0.0228 (8)−0.0009 (6)−0.0032 (6)−0.0024 (7)
C160.0250 (8)0.0248 (9)0.0271 (9)0.0035 (7)−0.0002 (7)−0.0026 (7)
Geometric parameters (Å, º) top
O1—C71.3662 (18)C5—C61.381 (2)
O1—C101.3998 (18)C5—H5A0.950
O2—C71.1995 (18)C8—C91.488 (2)
O3—C81.3659 (19)C9—H9A0.980
O3—C61.3923 (18)C9—H9B0.980
O4—C81.2013 (18)C9—H9C0.980
O5—C161.3090 (19)C10—C111.375 (2)
O5—H50.86 (1)C10—C151.396 (2)
O6—C161.2242 (18)C11—C121.383 (2)
C1—C61.395 (2)C11—H11A0.950
C1—C21.397 (2)C12—C131.381 (2)
C1—C71.480 (2)C12—H12A0.950
C2—C31.378 (2)C13—C141.379 (2)
C2—H2A0.950C13—H13A0.950
C3—C41.378 (2)C14—C151.391 (2)
C3—H3A0.950C14—H14A0.950
C4—C51.385 (2)C15—C161.480 (2)
C4—H4A0.950
C7—O1—C10115.71 (11)C8—C9—H9A109.5
C8—O3—C6117.58 (11)C8—C9—H9B109.5
C16—O5—H5108.2 (16)H9A—C9—H9B109.5
C6—C1—C2117.99 (14)C8—C9—H9C109.5
C6—C1—C7121.35 (13)H9A—C9—H9C109.5
C2—C1—C7120.63 (14)H9B—C9—H9C109.5
C3—C2—C1120.84 (15)C11—C10—C15121.20 (14)
C3—C2—H2A119.6C11—C10—O1117.20 (13)
C1—C2—H2A119.6C15—C10—O1121.59 (14)
C2—C3—C4120.23 (15)C10—C11—C12119.87 (14)
C2—C3—H3A119.9C10—C11—H11A120.1
C4—C3—H3A119.9C12—C11—H11A120.1
C3—C4—C5120.08 (14)C13—C12—C11120.00 (15)
C3—C4—H4A120.0C13—C12—H12A120.0
C5—C4—H4A120.0C11—C12—H12A120.0
C6—C5—C4119.63 (15)C14—C13—C12119.82 (15)
C6—C5—H5A120.2C14—C13—H13A120.1
C4—C5—H5A120.2C12—C13—H13A120.1
C5—C6—O3117.13 (13)C13—C14—C15121.24 (14)
C5—C6—C1121.20 (14)C13—C14—H14A119.4
O3—C6—C1121.54 (13)C15—C14—H14A119.4
O2—C7—O1121.63 (14)C14—C15—C10117.83 (14)
O2—C7—C1126.80 (14)C14—C15—C16117.59 (13)
O1—C7—C1111.55 (12)C10—C15—C16124.57 (14)
O4—C8—O3121.91 (14)O6—C16—O5122.61 (14)
O4—C8—C9127.32 (15)O6—C16—C15121.59 (14)
O3—C8—C9110.77 (13)O5—C16—C15115.77 (13)
C6—C1—C2—C31.1 (2)C6—O3—C8—O4−14.2 (2)
C7—C1—C2—C3−177.36 (13)C6—O3—C8—C9166.09 (12)
C1—C2—C3—C40.3 (2)C7—O1—C10—C11104.36 (15)
C2—C3—C4—C5−1.2 (2)C7—O1—C10—C15−76.66 (17)
C3—C4—C5—C60.6 (2)C15—C10—C11—C120.3 (2)
C4—C5—C6—O3176.69 (13)O1—C10—C11—C12179.32 (13)
C4—C5—C6—C10.9 (2)C10—C11—C12—C131.2 (2)
C8—O3—C6—C5115.45 (14)C11—C12—C13—C14−1.1 (2)
C8—O3—C6—C1−68.76 (17)C12—C13—C14—C15−0.6 (2)
C2—C1—C6—C5−1.7 (2)C13—C14—C15—C102.0 (2)
C7—C1—C6—C5176.74 (13)C13—C14—C15—C16−177.04 (14)
C2—C1—C6—O3−177.31 (12)C11—C10—C15—C14−1.9 (2)
C7—C1—C6—O31.1 (2)O1—C10—C15—C14179.14 (13)
C10—O1—C7—O20.9 (2)C11—C10—C15—C16177.09 (14)
C10—O1—C7—C1179.84 (11)O1—C10—C15—C16−1.8 (2)
C6—C1—C7—O2−6.4 (2)C14—C15—C16—O6−25.3 (2)
C2—C1—C7—O2172.01 (15)C10—C15—C16—O6155.67 (15)
C6—C1—C7—O1174.74 (12)C14—C15—C16—O5152.75 (14)
C2—C1—C7—O1−6.87 (18)C10—C15—C16—O5−26.3 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O5—H5···O6i0.86 (1)1.81 (1)2.6660 (16)176 (2)
Symmetry code: (i) −x, −y+1, −z+1.

Experimental details

Crystal data
Chemical formulaC16H12O6
Mr300.26
Crystal system, space groupMonoclinic, P21/c
Temperature (K)150
a, b, c (Å)9.6314 (5), 7.7548 (3), 18.0763 (8)
β (°) 95.572 (2)
V (Å3)1343.73 (11)
Z4
Radiation typeMo Kα
µ (mm−1)0.12
Crystal size (mm)0.40 × 0.20 × 0.02
Data collection
DiffractometerBruker Nonius X8 APEXII CCD
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.887, 0.998
No. of measured, independent and
observed [I > 2σ(I)] reflections		15807, 2367, 1868
Rint0.031
(sin θ/λ)max (Å−1)0.596
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.033, 0.080, 1.04
No. of reflections2367
No. of parameters204
No. of restraints1
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.18, −0.17

Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O5—H5···O6i0.86 (1)1.81 (1)2.6660 (16)176 (2)
Symmetry code: (i) −x, −y+1, −z+1.
 

Acknowledgements

We are grateful to the Danish Natural Science Research Council and the Carlsberg Foundation for provision of the X-ray equipment.

References

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ISSN: 2056-9890
Volume 68| Part 7| July 2012| Page o2108
https://doi.org/10.1107/S1600536812026475
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