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The structure of the title compound (systematic name: 2-{2-[1-(4-chloro­benzo­yl)-5-meth­oxy-2-methyl-1H-indol-3-yl]acet­oxy}­acetic acid monohydrate, C21H18ClNO6·H2O) contains one-dimensional infinite hydrogen-bonded chains. Mol­ecules of acemetacin, a nonsteroidal anti-inflammatory drug, and water are linked by three independent O—H...O bonds. The central unit in each chain consists of a sequence of alternating centrosymmetric R44(12) and R44(18) rings, which are edge-fused. Each ring links two acemetacin and two water mol­ecules. A comparison with seven related structures reveals that mol­ecules of acemetacin, indomethacin and their analogues can adopt two principal conformations.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107030065/jz3078sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107030065/jz3078Isup2.hkl
Contains datablock I

CCDC reference: 659126

Comment top

Acemetacin is a prodrug of indomethacin. It is a nonsteroidal anti-inflammatory drug used for the treatment of osteoarthritis, rheumatoid arthritis, low back pain, and post-operative inflammation and post-operative pain. Yoneda et al. (1981) described four polymorphic forms and two hydrates of acemetacin. Burger & Lettenbichler (1993) investigated five polymorphic forms, one monohydrate and the relatively stable amorphous form of acemetacin, and characterized these phases by means of thermomicroscopy, differential scanning calorimetry, thermogravimetry, IR spectroscopy, X-ray powder diffraction and pycnometry. Crystals of the monohydrate can be obtained from solutions with aqueous solvents. The existence of a second hydrate of acemetacin (Yoneda et al., 1981) was firmly rejected by Burger & Lettenbichler (1993). These authors explained the underlying observations as a consequence of an unusual melting behaviour of the monohydrate. Auer et al. (2003) investigated the FT–Raman spectra of six solid phases of acemetacin, and another account of the monohydrate was given by Kim et al. (1993). To date, no structural information relating to any of the six characterized crystalline phases of acemetacin is available from the Cambridge Structural Database (Version 5.28, November 2006; Allen, 2002).

A comparison of the powder pattern calculated from the structural model of the title compound discussed here with that reported by Burger & Lettenbichler (1993) for their monohydrate confirms that both studies were carried out on the same phase. The structure of the acemetacin molecule is shown in Fig. 1. Bond lengths and angles are unexceptional. The indole unit makes an angle of 69.03 (5)° with the chlorobenzyl fragment and an angle of 69.08 (6)° with the mean plane through the CCOO unit attached to atom C9.

The acemetacin molecule has one potential hydrogen-bond donor and the water molecule has two. These are engaged in three independent O—H···O hydrogen bonds linking the two types of molecule. The OH group of (I) acts as a hydrogen-bond donor to one water molecule (O5—H1O···O7), and two water H atoms are linked to carbonyl atoms O2 and O4 [O7—H2O···O2(x - 1, y, z) and O7—H3O···O4(-x - 1, -y, -z + 1); Table 1]. These acceptor atoms are located in the respective oxyacetic acid units of two different acemetacin molecules. The latter two molecules are related via a centre of inversion. Each water molecule bridges between three acemetacin molecules. In turn, each acemetacin molecule is hydrogen bonded to three water molecules. The described connections generate two fundamentally different centrosymmetric rings. The first ring can be characterized by the graph-set notation (Bernstein et al., 1995) R44 (12), and the other is an R44(18) ring. Rings of different types are edge-fused in such a way that C22(9) fragments are formed. Thus, infinite chains (Fig. 2) are generated, whose central unit consists of alternating R44 (12) and R44(18) rings. These one-dimensional hydrogen-bonded chains are centrosymmetric and propagate parallel to the a axis. The water molecules lie at the centre of each chain and all acemetacin molecules are oriented with their oxyacetic acid units towards the central unit, while their 4-chlorobenzoyl fragments point in the opposite direction. The stacking of the chains in the crystal structure is such that the central unit of a given chain is adjacent to the tail units of four neighbouring chains that are related to the former by a translation along [010], [010], [011], [010] and [011].

The closest intermolecular C—H···O intra-chain contacts are C17—H17A···O4(x + 1, y, z) and C3—H3 ···O6(x + 1, y, z). The shortest C—H···O contacts between acemetacin molecules belonging to different O—H···O bonded chains are C18—H18A···O2(-x, -y, -z + 1) and C20—H20A···O1(-x + 1, -y + 1, -z + 1).

The Cambridge Structural Database currently holds records for seven structures that contain the indomethacin molecule (α form: Chen et al., 2002; γ form: Cox & Manson, 2003a; MeOH solvate: Stowell et al., 2002; t-ButOH solvate: Cox & Manson, 2003b) or other close analogues of acemetacin (Loll et al., 1996; Trask et al., 2004; Bis & Zaworotko, 2005). The molecular conformations in these structures can be characterized in terms of two torsion angles, T1 (C—C—N—C) and T2 (C—C—C—N), which are indicated in Fig. 3 and tabulated in Table 2. The analysis of this list reveals that only two principal conformations exist. Type I and type II are associated with T1 values of approximately 150 and -30°, respectively, while T2 is between -30 and -55° for both types. Thus, the main difference between the alternative principal conformations is a rotation by 180° about the C—N bond. As a consequence, the CO bond and the Me substituent of the indol unit point either in the same direction (type I) or in opposite directions (type II). The conformation adopted by the acemetacin molecule in the title structure is of type I. It is noteworthy that the type I conformation is also adopted by the γ form and the t-BuOH solvate of indomethacin, and also by two of the three independent molecules of the α form, while the conformation of the third molecule in this modification is of type II.

The hydrogen bonding in the MeOH and t-BuOH solvates of indomethacin is such that molecules of different types are linked by hydrogen bonds. The COOH group of indomethacin is employed in these interactions in the same fashion in which the COOH units are engaged in hydrogen bonding between acemetacin and water in Fig. 2. Thus, the indomethacin solvates form a very similar kind of R44 (12) ring, where the OH group of the solvent replaces water. However, the lack of additional OH donors in the indomethacin molecules prevents further aggregation of these rings via classical hydrogen bonds, so that the hydrogen-bonded structure in these solvates is dimeric.

Related literature top

For related literature, see: Allen (2002); Auer et al. (2003); Bernstein et al. (1995); Bis & Zaworotko (2005); Burger & Lettenbichler (1993); Cox & Manson (2003a, 2003b); Kim et al. (1993); Trask et al. (2004); Yoneda et al. (1981).

Experimental top

Acemetacin was supplied by Bayer. Colourless prismatic crystals of the title compound were formed by slow evaporation of an acetone/water solution at room temperature.

Refinement top

Methyl H atoms were located in difference syntheses, idealized and included as rigid groups allowed to rotate but not tip. Other C-bonded H atoms were positioned geometrically and refined using a riding model with Uiso(H) values of 1.2Ueq(C) for CH and CH2 or 1.5 Ueq(C) for CH3 H atoms. The C—H bond lengths were set at 0.95 (aromatic), 0.99 (CH2) or 0.98 Å (CH3). H atoms attached to O were refined using geometrical restraints [O—H = 0.82 (s.u. value?) Å and Uiso(H) = 1.2Ueq(O) for OH, and O—H = 0.88 (s.u. value?) Å and Uiso(H) = 1.5Ueq(O) for H2O].

Computing details top

Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Bruker, 1998) and Mercury (Bruno et al., 2002); software used to prepare material for publication: program (reference)?.

Figures top
[Figure 1] Fig. 1. : The molecular structure of (I), showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. : Part of a hydrogen-bonded chain composed of edge-fused R44(12) and R44(18) rings.
[Figure 3] Fig. 3. : The common structural unit of the compounds listed in Table 1 and definition of the torsion angles T1 and T2 for acemetacin [R = –CH2C(O)OCH2COOH and hal = Cl], indomethacin (R = –CH2COOH and hal = Cl), iodoindomethacin (R = –CH2COOH and hal = I) and indomethacin methyl ester (R = –CH2COOMe and hal = Cl).
2-{2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetoxy}acetic acid monohydrate top
Crystal data top
C21H18ClNO6·H2OV = 993.44 (6) Å3
Mr = 433.83Z = 2
Triclinic, P1F(000) = 452
a = 7.7257 (3) ÅDx = 1.450 Mg m3
b = 10.2208 (3) ÅMo Kα radiation, λ = 0.71073 Å
c = 13.4225 (4) ŵ = 0.24 mm1
α = 96.879 (2)°T = 120 K
β = 96.354 (2)°Block, colourless
γ = 107.158 (2)°0.25 × 0.15 × 0.10 mm
Data collection top
Bruker–Nonius KappaCCD
diffractometer
3877 independent reflections
Radiation source: Bruker-Nonius FR591 rotating anode3065 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.072
Detector resolution: 9.091 pixels mm-1θmax = 26.0°, θmin = 3.1°
ϕ and ω scansh = 99
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
k = 1212
Tmin = 0.943, Tmax = 0.977l = 1616
12459 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.046H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.127 w = 1/[σ2(Fo2) + (0.0592P)2 + 0.1261P]
where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max < 0.001
3877 reflectionsΔρmax = 0.30 e Å3
285 parametersΔρmin = 0.30 e Å3
3 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.038 (5)
Crystal data top
C21H18ClNO6·H2Oγ = 107.158 (2)°
Mr = 433.83V = 993.44 (6) Å3
Triclinic, P1Z = 2
a = 7.7257 (3) ÅMo Kα radiation
b = 10.2208 (3) ŵ = 0.24 mm1
c = 13.4225 (4) ÅT = 120 K
α = 96.879 (2)°0.25 × 0.15 × 0.10 mm
β = 96.354 (2)°
Data collection top
Bruker–Nonius KappaCCD
diffractometer
3877 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
3065 reflections with I > 2σ(I)
Tmin = 0.943, Tmax = 0.977Rint = 0.072
12459 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0463 restraints
wR(F2) = 0.127H atoms treated by a mixture of independent and constrained refinement
S = 1.09Δρmax = 0.30 e Å3
3877 reflectionsΔρmin = 0.30 e Å3
285 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
Cl10.82421 (9)0.97907 (6)1.19332 (4)0.0352 (2)
O10.7465 (2)0.71885 (14)0.70347 (10)0.0248 (3)
O20.02241 (19)0.11031 (13)0.42336 (9)0.0190 (3)
O30.02130 (19)0.32192 (13)0.48914 (9)0.0190 (3)
O40.3234 (2)0.14800 (15)0.48895 (10)0.0253 (4)
O50.4141 (2)0.16934 (15)0.32904 (11)0.0251 (4)
H1O0.509 (2)0.1109 (19)0.3375 (18)0.030*
O60.2004 (2)0.39859 (15)0.85113 (11)0.0268 (4)
N10.4902 (2)0.56238 (16)0.73859 (11)0.0153 (4)
C10.7699 (3)0.8912 (2)1.06917 (14)0.0228 (5)
C20.7285 (3)0.7475 (2)1.05192 (14)0.0209 (4)
H20.73080.69781.10720.020 (5)*
C30.6837 (3)0.6783 (2)0.95270 (14)0.0198 (4)
H30.65270.58010.93970.018 (5)*
C40.6842 (3)0.75229 (19)0.87203 (14)0.0171 (4)
C50.7296 (3)0.8957 (2)0.89063 (15)0.0239 (5)
H50.73260.94600.83540.029*
C60.7706 (3)0.9660 (2)0.98975 (16)0.0275 (5)
H60.79871.06401.00280.033*
C70.6453 (3)0.68014 (19)0.76454 (14)0.0169 (4)
C80.4685 (3)0.45221 (19)0.65816 (13)0.0159 (4)
C90.2982 (3)0.36006 (19)0.64934 (13)0.0156 (4)
C100.2023 (3)0.41159 (18)0.72410 (13)0.0147 (4)
C110.3236 (3)0.53751 (19)0.77830 (13)0.0159 (4)
C120.2659 (3)0.6171 (2)0.85194 (14)0.0193 (4)
H120.34550.70430.88640.023*
C130.0900 (3)0.5650 (2)0.87299 (14)0.0210 (4)
H130.04900.61700.92340.025*
C140.0299 (3)0.4368 (2)0.82161 (14)0.0192 (4)
C150.0240 (3)0.3595 (2)0.74567 (14)0.0171 (4)
H150.05770.27400.70950.021*
C160.3149 (3)0.2599 (2)0.81564 (18)0.0312 (5)
H16A0.42660.24250.84690.047*
H16B0.24930.19540.83390.047*
H16C0.34760.24630.74160.047*
C170.6225 (3)0.4443 (2)0.60195 (15)0.0221 (5)
H17A0.59270.35110.56270.033*
H17B0.73490.46360.65050.033*
H17C0.64100.51290.55580.033*
C180.2235 (3)0.2232 (2)0.57940 (14)0.0183 (4)
H18A0.16960.15140.62030.022*
H18B0.32810.20030.55370.022*
C190.0815 (3)0.21120 (19)0.48913 (14)0.0160 (4)
C200.1183 (3)0.3084 (2)0.40441 (14)0.0193 (4)
H20A0.07510.28310.34030.023*
H20B0.14120.39850.40270.023*
C210.2938 (3)0.19914 (19)0.41263 (14)0.0183 (4)
O70.7202 (2)0.00602 (14)0.35206 (10)0.0227 (3)
H2O0.801 (3)0.036 (2)0.3628 (18)0.034*
H3O0.707 (4)0.049 (2)0.4037 (13)0.034*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0458 (4)0.0342 (3)0.0170 (3)0.0038 (3)0.0023 (2)0.0052 (2)
O10.0243 (8)0.0249 (8)0.0205 (7)0.0001 (6)0.0068 (6)0.0027 (6)
O20.0213 (8)0.0175 (7)0.0153 (7)0.0034 (6)0.0020 (5)0.0011 (5)
O30.0199 (7)0.0167 (7)0.0183 (7)0.0053 (6)0.0017 (6)0.0008 (5)
O40.0256 (8)0.0307 (8)0.0213 (7)0.0085 (7)0.0059 (6)0.0089 (6)
O50.0183 (8)0.0283 (8)0.0244 (7)0.0012 (6)0.0012 (6)0.0072 (6)
O60.0183 (8)0.0253 (8)0.0348 (8)0.0036 (6)0.0115 (6)0.0016 (6)
N10.0146 (8)0.0148 (8)0.0147 (8)0.0026 (7)0.0024 (6)0.0001 (6)
C10.0202 (11)0.0271 (11)0.0167 (9)0.0036 (9)0.0006 (8)0.0017 (8)
C20.0199 (11)0.0255 (11)0.0190 (10)0.0079 (9)0.0033 (8)0.0076 (8)
C30.0169 (10)0.0201 (10)0.0218 (10)0.0052 (8)0.0021 (8)0.0032 (8)
C40.0132 (10)0.0181 (10)0.0170 (9)0.0016 (8)0.0014 (7)0.0005 (7)
C50.0285 (12)0.0204 (10)0.0197 (10)0.0029 (9)0.0011 (9)0.0063 (8)
C60.0354 (13)0.0176 (10)0.0251 (11)0.0029 (10)0.0037 (9)0.0011 (8)
C70.0174 (10)0.0179 (9)0.0162 (9)0.0062 (8)0.0023 (8)0.0036 (7)
C80.0180 (10)0.0176 (9)0.0121 (8)0.0067 (8)0.0009 (7)0.0012 (7)
C90.0166 (10)0.0165 (9)0.0133 (8)0.0056 (8)0.0004 (7)0.0020 (7)
C100.0180 (10)0.0137 (9)0.0121 (8)0.0054 (8)0.0000 (7)0.0023 (7)
C110.0145 (10)0.0180 (9)0.0153 (9)0.0051 (8)0.0010 (7)0.0043 (7)
C120.0186 (10)0.0187 (10)0.0183 (9)0.0041 (8)0.0009 (8)0.0003 (8)
C130.0229 (11)0.0223 (10)0.0183 (9)0.0090 (9)0.0048 (8)0.0014 (8)
C140.0162 (10)0.0222 (10)0.0206 (10)0.0075 (9)0.0040 (8)0.0038 (8)
C150.0172 (10)0.0163 (9)0.0180 (9)0.0056 (8)0.0011 (8)0.0042 (7)
C160.0261 (12)0.0244 (11)0.0415 (13)0.0028 (10)0.0150 (10)0.0032 (10)
C170.0218 (11)0.0221 (10)0.0210 (10)0.0049 (9)0.0066 (8)0.0002 (8)
C180.0209 (11)0.0169 (9)0.0167 (9)0.0071 (8)0.0009 (8)0.0002 (8)
C190.0163 (10)0.0155 (9)0.0165 (9)0.0038 (8)0.0062 (8)0.0031 (8)
C200.0189 (11)0.0202 (10)0.0174 (9)0.0043 (8)0.0004 (8)0.0058 (8)
C210.0210 (11)0.0187 (10)0.0188 (9)0.0120 (9)0.0042 (8)0.0011 (8)
O70.0229 (8)0.0239 (8)0.0228 (7)0.0101 (6)0.0025 (6)0.0037 (6)
Geometric parameters (Å, º) top
Cl1—C11.7389 (19)C9—C101.450 (3)
O1—C71.215 (2)C9—C181.504 (3)
O2—C191.211 (2)C10—C151.399 (3)
O3—C191.345 (2)C10—C111.406 (3)
O3—C201.442 (2)C11—C121.398 (3)
O4—C211.218 (2)C12—C131.380 (3)
O5—C211.317 (2)C12—H120.9500
O5—H1O0.828 (10)C13—C141.406 (3)
O6—C141.376 (2)C13—H130.9500
O6—C161.423 (3)C14—C151.390 (3)
N1—C71.401 (3)C15—H150.9500
N1—C111.413 (2)C16—H16A0.9800
N1—C81.421 (2)C16—H16B0.9800
C1—C61.384 (3)C16—H16C0.9800
C1—C21.392 (3)C17—H17A0.9800
C2—C31.386 (3)C17—H17B0.9800
C2—H20.9500C17—H17C0.9800
C3—C41.393 (3)C18—C191.509 (3)
C3—H30.9500C18—H18A0.9900
C4—C51.387 (3)C18—H18B0.9900
C4—C71.495 (2)C20—C211.506 (3)
C5—C61.389 (3)C20—H20A0.9900
C5—H50.9500C20—H20B0.9900
C6—H60.9500O7—H2O0.872 (10)
C8—C91.356 (3)O7—H3O0.875 (10)
C8—C171.494 (3)
C19—O3—C20113.79 (14)C11—C12—H12121.0
C21—O5—H1O108.8 (17)C12—C13—C14121.61 (17)
C14—O6—C16117.09 (15)C12—C13—H13119.2
C7—N1—C11127.42 (15)C14—C13—H13119.2
C7—N1—C8124.35 (16)O6—C14—C15124.37 (18)
C11—N1—C8107.93 (15)O6—C14—C13114.87 (16)
C6—C1—C2121.52 (18)C15—C14—C13120.75 (19)
C6—C1—Cl1119.18 (16)C14—C15—C10117.92 (18)
C2—C1—Cl1119.30 (16)C14—C15—H15121.0
C3—C2—C1118.88 (18)C10—C15—H15121.0
C3—C2—H2120.6O6—C16—H16A109.5
C1—C2—H2120.6O6—C16—H16B109.5
C2—C3—C4120.20 (18)H16A—C16—H16B109.5
C2—C3—H3119.9O6—C16—H16C109.5
C4—C3—H3119.9H16A—C16—H16C109.5
C5—C4—C3120.11 (17)H16B—C16—H16C109.5
C5—C4—C7118.86 (17)C8—C17—H17A109.5
C3—C4—C7120.95 (17)C8—C17—H17B109.5
C6—C5—C4120.22 (19)H17A—C17—H17B109.5
C6—C5—H5119.9C8—C17—H17C109.5
C4—C5—H5119.9H17A—C17—H17C109.5
C1—C6—C5119.05 (19)H17B—C17—H17C109.5
C1—C6—H6120.5C9—C18—C19117.85 (15)
C5—C6—H6120.5C9—C18—H18A107.8
O1—C7—N1121.53 (17)C19—C18—H18A107.8
O1—C7—C4121.71 (18)C9—C18—H18B107.8
N1—C7—C4116.72 (17)C19—C18—H18B107.8
C9—C8—N1109.04 (16)H18A—C18—H18B107.2
C9—C8—C17129.21 (17)O2—C19—O3122.27 (16)
N1—C8—C17121.62 (17)O2—C19—C18123.77 (16)
C8—C9—C10108.25 (16)O3—C19—C18113.94 (15)
C8—C9—C18126.56 (17)O3—C20—C21110.87 (15)
C10—C9—C18125.08 (18)O3—C20—H20A109.5
C15—C10—C11120.99 (17)C21—C20—H20A109.5
C15—C10—C9131.78 (17)O3—C20—H20B109.5
C11—C10—C9107.22 (17)C21—C20—H20B109.5
C12—C11—C10120.64 (18)H20A—C20—H20B108.1
C12—C11—N1131.70 (18)O4—C21—O5124.0 (2)
C10—C11—N1107.54 (15)O4—C21—C20123.89 (17)
C13—C12—C11118.01 (18)O5—C21—C20112.08 (16)
C13—C12—H12121.0H2O—O7—H3O107 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O5—H1O···O70.83 (1)1.76 (1)2.587 (2)176 (2)
O7—H2O···O2i0.87 (1)1.95 (1)2.7980 (19)164 (2)
O7—H3O···O4ii0.88 (1)1.89 (1)2.7649 (19)177 (2)
C20—H20A···O1iii0.992.673.424 (3)133
C18—H18A···O2iv0.992.613.371 (2)134
C17—H17A···O4v0.982.483.381 (2)153
C3—H3···O6v0.952.673.417 (2)136
Symmetry codes: (i) x1, y, z; (ii) x1, y, z+1; (iii) x+1, y+1, z+1; (iv) x, y, z+1; (v) x+1, y, z.

Experimental details

Crystal data
Chemical formulaC21H18ClNO6·H2O
Mr433.83
Crystal system, space groupTriclinic, P1
Temperature (K)120
a, b, c (Å)7.7257 (3), 10.2208 (3), 13.4225 (4)
α, β, γ (°)96.879 (2), 96.354 (2), 107.158 (2)
V3)993.44 (6)
Z2
Radiation typeMo Kα
µ (mm1)0.24
Crystal size (mm)0.25 × 0.15 × 0.10
Data collection
DiffractometerBruker–Nonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.943, 0.977
No. of measured, independent and
observed [I > 2σ(I)] reflections
12459, 3877, 3065
Rint0.072
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.127, 1.09
No. of reflections3877
No. of parameters285
No. of restraints3
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.30, 0.30

Computer programs: COLLECT (Hooft, 1998), DENZO (Otwinowski & Minor, 1997) and COLLECT, DENZO and COLLECT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), XP (Bruker, 1998) and Mercury (Bruno et al., 2002), program (reference)?.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O5—H1O···O70.828 (10)1.760 (10)2.587 (2)176 (2)
O7—H2O···O2i0.872 (10)1.950 (12)2.7980 (19)164 (2)
O7—H3O···O4ii0.875 (10)1.891 (10)2.7649 (19)177 (2)
C20—H20A···O1iii0.992.673.424 (3)132.8
C18—H18A···O2iv0.992.613.371 (2)134.2
C17—H17A···O4v0.982.483.381 (2)152.6
C3—H3···O6v0.952.673.417 (2)135.5
Symmetry codes: (i) x1, y, z; (ii) x1, y, z+1; (iii) x+1, y+1, z+1; (iv) x, y, z+1; (v) x+1, y, z.
Solid-state conformation types I and II of acemetacin and related molecules indicated by torsion angles T1 and T2 (see Fig. 3) top
Crystal structureMoleculeT1 (°)T2 (°)ConformationReference
Acemetacin monohydrateA154.3-48.7Ithis work
Indomethacin t-ButOH solvateA147.8-38.4ICox & Manson (2003b)
2-Amino-5-picolinium indomethacinA146.9-29.7IBis & Zaworotko (2005)
B148.9-30.6I
γ-IndomethacinA150.8-40.7ICox & Manson (2003a)
α-IndomethacinA153.6-53.3IChen et al. (2002)
C154.4-52.9I
B-22.7-54.5II
Indomethacin MeOH solvateA-36.9-44.9IIStowell et al. (2002)
IodoindomethacinA-35.0-44.3IILoll et al. (1996)
Indomethacin methyl esterA-33.0-51.4IITrask et al. (2004)
 

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