organic compounds
2-Chloro-N-[4-chloro-2-(2-chlorobenzoyl)phenyl]acetamide
aDepartment of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland, bDepartment of Chemistry, V. V. Puram College of Science, Bangalore 560004, India, cDepartment of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India, and dDepartment of Studies in Chemistry, Mangalore University, Mangalagangotri 574 199, India
*Correspondence e-mail: mkubicki@amu.edu.pl
In the title compound, C15H10Cl3NO2, an intramolecular N—H⋯O hydrogen bond forms a six-membered ring and enforces an almost coplanar conformation for the acetamido group, the central benzene ring and the bridging carbonyl C—C(=O)—C group: the dihedral angles between the benzene ring and the acetamide and carbonyl C—C(=O)—C planes are 7.06 (11) and 7.17 (12)°, respectively. The dihedral angle between the two benzene rings is 67.43 (9)°. Because a strong hydrogen-bond donor is involved in the intramolecular interaction, the crystal packing is determined by weak C—H⋯O and C—H⋯Cl interactions.
Related literature
The title compound is isostructural with 2-chloroacetamido-5-chloro-2′-fluorobenzophenone (Prasanna & Guru Row, 2000). For the isostructurality index, see: Kálmán et al. (1991); Kubicki & Szafrański (1998). For a related structure, see: Malathy Sony et al. (2005). For the biological activity of benzophenone derivatives, see: Evans et al. (1987). For a description of the Cambridge Structural Database, see: Allen (2002).
Experimental
Crystal data
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Refinement
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Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Stereochemical Workstation Operation Manual (Siemens, 1989); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S1600536810003375/is2519sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810003375/is2519Isup2.hkl
The title compound was obtained as a gift sample from R. L. FineChem, Bangalore, India. The compound was used without further purification. X-ray quality crystals were obtained by slow evaporation from ethyl acetate solution (m.p. 436-438 K).
Benzophenone and related compounds have been reported to act as e.g., antiallergic, anti-inflammatory, antiasthmatic, antimalarial, anti-microbial and antianaphylactic agents (Evans et al., 1987). Here we report the
of 2-chloroacetamido-5-chloro-2'-chlorobenzophenone (alternative name: 2-chloro-N-{4-chloro-2-[(2-chlorophenyl)carbonyl]phenyl}acetamide; 1, Scheme 1), which is an intermediate in the synthesis of certain anxiolytic, anticonvulsant and sedative drugs, and is also a starting material for the synthesis of diazepam and other benzodiazepines.The structure of 1 is isostructural with the previously described 2-chloroacetamido-5-chloro-2'-fluorobenzophenone derivative (Prasanna & Guru Row, 2000). Both compounds crystallize in the triclinic P-1
and the dimensions are similar. Also the positions of the atoms in the are similar, after applying the transformation (index 1 refers to Prasanna & Guru Row, 2 - to the present structure): x2=x1+0.5, y2=y1+0.5, z2=z1+1.5. The isostructurality index (Kálmán et al., 1991), which describes the differences between the positions of the atoms in the has the value of 97.4% (for perfect isostructurality it should be 100%). Kubicki & Szafrański (1998) proposed the modification of this latter parameter which takes into account the symmetry and gives more absolute measure of the degree of isostructurality: it should be 1 for ideally isomorphous compounds and 0 for randomly distributed atoms. The value of this modified index is 0.94.The conformation of 1 (Fig. 1) might be described by dihedral angles between four approximately planar fragments: acetamide [A, planar within 0.0065 (19) Å, with Cl2 atom significantly, by 0.110 (5)Å out of the plane], central phenyl [B, maximum deviation 0.0034 (14) Å], bridging carbonyl group C—C(=O)-C [C, max. deviation 0.015 (2) Å], and terminal phenyl [D, 0.0045 (19) Å]. The first three are close to coplanarity, the dihedral angles are A/B 7.06 (11)° and B/C 7.17 (12)°. Such a coplanar conformation of phenyl and carbonyl plane is quite uncommon for benzophenones, in a majority of the compounds found in the CSD (Allen, 2002) both phenyl rings are almost equally, and significantly, twisted with respect to the central plane. In the case of 1, as in some similar cases (for instance in the isostructural 2'-fluoro derivative but also in two crystal forms of 2-chloroacetamido-5-chlorobenzophenone (monoclinic: Prasanna & Guru Row, 2000, and triclinic: Malathy Sony et al., 2005), the factor responsible for such a coplanar conformation is the intramolecular hydrogen bond N—H···O (cf. Table 1). This hydrogen bond closes the six-membered ring, planar within 0.072 (7) Å. The second phenyl ring, which has no factor that can stabilize coplanar conformation, is typically, by 62.14 (10)°, twisted with respect to the bridge. The Cl atom of chloroacetamide group is anti with respect to the oxygen atom [O10—C9—C11—Cl12 torsion angle of 176.4 (2)°] and syn with respect to the N atom [N8—C9—C11—Cl12 is -4.8 (3)°]
In the
there are some weak C—H···O and C—H···Cl interactions, which might be of some importance when the strong hydrogen bond donor is involved in intramolecular interaction (Fig. 2)The title compound is isostructural with 2-chloroacetamido-5-chloro-2'-fluorobenzophenone (Prasanna & Guru Row, 2000). For the isostructurality index, see: Kálmán et al. (1991); Kubicki & Szafrański (1998). For a related structure, see: Malathy Sony et al. (2005). For the biological activity of benzophenone derivatives, see: Evans et al. (1987). For a description of the Cambridge Structural Database, see: Allen (2002).
Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell
CrysAlis PRO (Oxford Diffraction, 2009); data reduction: CrysAlis PRO (Oxford Diffraction, 2009); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Stereochemical Workstation Operation Manual (Siemens, 1989); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C15H10Cl3NO2 | Z = 2 |
Mr = 342.59 | F(000) = 348 |
Triclinic, P1 | Dx = 1.558 Mg m−3 |
Hall symbol: -P 1 | Cu Kα radiation, λ = 1.54178 Å |
a = 7.5776 (9) Å | Cell parameters from 3832 reflections |
b = 10.1565 (10) Å | θ = 4.4–75.1° |
c = 10.7862 (12) Å | µ = 5.71 mm−1 |
α = 70.069 (8)° | T = 295 K |
β = 77.604 (9)° | Prism, pink |
γ = 70.388 (8)° | 0.35 × 0.2 × 0.2 mm |
V = 730.47 (14) Å3 |
Oxford Diffraction SuperNova (single source at offset) Atlas diffractometer | 2917 independent reflections |
Radiation source: SuperNova (Cu) X-ray Source | 2610 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.017 |
Detector resolution: 10.5357 pixels mm-1 | θmax = 75.2°, θmin = 4.4° |
ω–scan | h = −9→9 |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) | k = −12→12 |
Tmin = 0.117, Tmax = 0.319 | l = −13→13 |
5245 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.043 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.113 | All H-atom parameters refined |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0551P)2 + 0.3949P] where P = (Fo2 + 2Fc2)/3 |
2917 reflections | (Δ/σ)max = 0.001 |
230 parameters | Δρmax = 0.37 e Å−3 |
0 restraints | Δρmin = −0.44 e Å−3 |
C15H10Cl3NO2 | γ = 70.388 (8)° |
Mr = 342.59 | V = 730.47 (14) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.5776 (9) Å | Cu Kα radiation |
b = 10.1565 (10) Å | µ = 5.71 mm−1 |
c = 10.7862 (12) Å | T = 295 K |
α = 70.069 (8)° | 0.35 × 0.2 × 0.2 mm |
β = 77.604 (9)° |
Oxford Diffraction SuperNova (single source at offset) Atlas diffractometer | 2917 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) | 2610 reflections with I > 2σ(I) |
Tmin = 0.117, Tmax = 0.319 | Rint = 0.017 |
5245 measured reflections |
R[F2 > 2σ(F2)] = 0.043 | 0 restraints |
wR(F2) = 0.113 | All H-atom parameters refined |
S = 1.05 | Δρmax = 0.37 e Å−3 |
2917 reflections | Δρmin = −0.44 e Å−3 |
230 parameters |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2σ(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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.2330 (3) | 0.4690 (2) | 0.74281 (19) | 0.0407 (4) | |
O1 | 0.1250 (3) | 0.58486 (19) | 0.68930 (16) | 0.0679 (5) | |
C2 | 0.2780 (3) | 0.4324 (2) | 0.87982 (17) | 0.0347 (4) | |
C3 | 0.3816 (3) | 0.2896 (2) | 0.94118 (19) | 0.0391 (4) | |
H3 | 0.422 (3) | 0.219 (2) | 0.889 (2) | 0.043 (6)* | |
C4 | 0.4253 (3) | 0.2515 (2) | 1.06806 (19) | 0.0419 (4) | |
Cl4 | 0.55643 (9) | 0.07373 (6) | 1.14246 (6) | 0.05951 (19) | |
C5 | 0.3676 (3) | 0.3534 (2) | 1.1378 (2) | 0.0482 (5) | |
H5 | 0.393 (4) | 0.325 (3) | 1.228 (3) | 0.074 (9)* | |
C6 | 0.2645 (3) | 0.4939 (2) | 1.0804 (2) | 0.0454 (5) | |
H6 | 0.230 (4) | 0.562 (3) | 1.129 (3) | 0.059 (7)* | |
C7 | 0.2178 (3) | 0.5364 (2) | 0.95170 (18) | 0.0358 (4) | |
N8 | 0.1173 (3) | 0.67993 (18) | 0.88973 (17) | 0.0415 (4) | |
H8 | 0.094 (4) | 0.696 (3) | 0.812 (3) | 0.067 (8)* | |
C9 | 0.0393 (3) | 0.7935 (2) | 0.9426 (2) | 0.0448 (5) | |
O10 | 0.0375 (3) | 0.78715 (18) | 1.05679 (17) | 0.0650 (5) | |
C11 | −0.0562 (4) | 0.9388 (3) | 0.8497 (3) | 0.0545 (6) | |
H11B | −0.006 (4) | 1.010 (3) | 0.851 (3) | 0.066 (8)* | |
H11A | −0.189 (5) | 0.970 (4) | 0.878 (3) | 0.083 (10)* | |
Cl12 | −0.03818 (13) | 0.94573 (7) | 0.68136 (7) | 0.0826 (3) | |
C13 | 0.3127 (3) | 0.3605 (2) | 0.66429 (18) | 0.0403 (4) | |
C14 | 0.5017 (3) | 0.3148 (2) | 0.61956 (19) | 0.0465 (5) | |
Cl14 | 0.66554 (9) | 0.37077 (10) | 0.66357 (7) | 0.0759 (2) | |
C15 | 0.5645 (5) | 0.2289 (3) | 0.5339 (2) | 0.0701 (9) | |
H15 | 0.693 (6) | 0.200 (4) | 0.509 (4) | 0.102 (12)* | |
C16 | 0.4381 (7) | 0.1877 (3) | 0.4935 (3) | 0.0855 (12) | |
H16 | 0.478 (5) | 0.129 (4) | 0.433 (4) | 0.109 (12)* | |
C17 | 0.2507 (8) | 0.2312 (4) | 0.5360 (3) | 0.0885 (12) | |
H17 | 0.162 (6) | 0.198 (4) | 0.511 (4) | 0.110 (13)* | |
C18 | 0.1858 (5) | 0.3185 (3) | 0.6211 (3) | 0.0646 (7) | |
H18 | 0.054 (4) | 0.345 (3) | 0.647 (3) | 0.064 (8)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0457 (11) | 0.0416 (10) | 0.0345 (9) | −0.0059 (8) | −0.0076 (8) | −0.0154 (8) |
O1 | 0.0874 (13) | 0.0584 (10) | 0.0450 (9) | 0.0187 (9) | −0.0284 (8) | −0.0254 (8) |
C2 | 0.0395 (9) | 0.0372 (9) | 0.0292 (8) | −0.0102 (8) | −0.0037 (7) | −0.0129 (7) |
C3 | 0.0472 (11) | 0.0362 (9) | 0.0353 (9) | −0.0107 (8) | −0.0050 (8) | −0.0129 (8) |
C4 | 0.0495 (11) | 0.0382 (10) | 0.0356 (9) | −0.0121 (8) | −0.0076 (8) | −0.0065 (8) |
Cl4 | 0.0745 (4) | 0.0419 (3) | 0.0526 (3) | −0.0059 (3) | −0.0225 (3) | −0.0034 (2) |
C5 | 0.0644 (14) | 0.0501 (12) | 0.0308 (9) | −0.0150 (10) | −0.0110 (9) | −0.0105 (9) |
C6 | 0.0595 (13) | 0.0464 (11) | 0.0339 (10) | −0.0124 (9) | −0.0062 (9) | −0.0185 (9) |
C7 | 0.0415 (10) | 0.0362 (9) | 0.0319 (9) | −0.0112 (8) | −0.0031 (7) | −0.0132 (7) |
N8 | 0.0518 (10) | 0.0364 (8) | 0.0364 (9) | −0.0057 (7) | −0.0076 (7) | −0.0161 (7) |
C9 | 0.0521 (12) | 0.0401 (10) | 0.0465 (11) | −0.0124 (9) | −0.0024 (9) | −0.0205 (9) |
O10 | 0.0977 (14) | 0.0495 (9) | 0.0508 (9) | −0.0098 (9) | −0.0101 (9) | −0.0283 (8) |
C11 | 0.0611 (15) | 0.0390 (11) | 0.0633 (14) | −0.0044 (10) | −0.0096 (12) | −0.0231 (10) |
Cl12 | 0.1198 (6) | 0.0491 (3) | 0.0563 (4) | 0.0106 (4) | −0.0247 (4) | −0.0128 (3) |
C13 | 0.0556 (12) | 0.0394 (10) | 0.0296 (9) | −0.0123 (9) | −0.0095 (8) | −0.0129 (7) |
C14 | 0.0579 (12) | 0.0412 (10) | 0.0317 (9) | 0.0000 (9) | −0.0095 (9) | −0.0111 (8) |
Cl14 | 0.0489 (3) | 0.1181 (6) | 0.0624 (4) | −0.0212 (4) | −0.0057 (3) | −0.0312 (4) |
C15 | 0.101 (2) | 0.0478 (13) | 0.0343 (11) | 0.0192 (14) | −0.0117 (13) | −0.0156 (10) |
C16 | 0.172 (4) | 0.0390 (12) | 0.0384 (13) | −0.0081 (17) | −0.0247 (18) | −0.0161 (10) |
C17 | 0.171 (4) | 0.074 (2) | 0.0541 (16) | −0.064 (2) | −0.033 (2) | −0.0190 (15) |
C18 | 0.0825 (19) | 0.0759 (17) | 0.0535 (14) | −0.0381 (15) | −0.0126 (13) | −0.0231 (13) |
C1—O1 | 1.217 (3) | C9—O10 | 1.209 (3) |
C1—C2 | 1.482 (2) | C9—C11 | 1.514 (3) |
C1—C13 | 1.506 (3) | C11—Cl12 | 1.770 (3) |
C2—C3 | 1.401 (3) | C11—H11B | 0.93 (3) |
C2—C7 | 1.417 (2) | C11—H11A | 0.96 (3) |
C3—C4 | 1.371 (3) | C13—C14 | 1.381 (3) |
C3—H3 | 0.99 (2) | C13—C18 | 1.388 (3) |
C4—C5 | 1.383 (3) | C14—C15 | 1.387 (3) |
C4—Cl4 | 1.744 (2) | C14—Cl14 | 1.732 (2) |
C5—C6 | 1.374 (3) | C15—C16 | 1.363 (5) |
C5—H5 | 0.96 (3) | C15—H15 | 0.92 (4) |
C6—C7 | 1.392 (3) | C16—C17 | 1.363 (6) |
C6—H6 | 0.94 (3) | C16—H16 | 0.97 (4) |
C7—N8 | 1.401 (3) | C17—C18 | 1.392 (4) |
N8—C9 | 1.361 (3) | C17—H17 | 0.96 (4) |
N8—H8 | 0.84 (3) | C18—H18 | 0.95 (3) |
O1—C1—C2 | 122.49 (17) | N8—C9—C11 | 116.46 (19) |
O1—C1—C13 | 116.25 (17) | C9—C11—Cl12 | 116.35 (15) |
C2—C1—C13 | 121.21 (17) | C9—C11—H11B | 109.2 (18) |
C3—C2—C7 | 118.78 (17) | Cl12—C11—H11B | 106.8 (18) |
C3—C2—C1 | 118.91 (16) | C9—C11—H11A | 111 (2) |
C7—C2—C1 | 122.30 (17) | Cl12—C11—H11A | 106 (2) |
C4—C3—C2 | 120.57 (18) | H11B—C11—H11A | 107 (3) |
C4—C3—H3 | 122.2 (13) | C14—C13—C18 | 118.3 (2) |
C2—C3—H3 | 117.3 (13) | C14—C13—C1 | 123.67 (19) |
C3—C4—C5 | 120.60 (19) | C18—C13—C1 | 117.5 (2) |
C3—C4—Cl4 | 120.01 (16) | C13—C14—C15 | 121.3 (3) |
C5—C4—Cl4 | 119.38 (16) | C13—C14—Cl14 | 120.50 (15) |
C6—C5—C4 | 120.02 (19) | C15—C14—Cl14 | 118.2 (2) |
C6—C5—H5 | 119.4 (18) | C16—C15—C14 | 119.6 (3) |
C4—C5—H5 | 120.5 (18) | C16—C15—H15 | 123 (2) |
C5—C6—C7 | 120.93 (19) | C14—C15—H15 | 117 (2) |
C5—C6—H6 | 118.3 (16) | C15—C16—C17 | 120.4 (2) |
C7—C6—H6 | 120.8 (16) | C15—C16—H16 | 121 (2) |
C6—C7—N8 | 121.99 (17) | C17—C16—H16 | 118 (2) |
C6—C7—C2 | 119.09 (18) | C16—C17—C18 | 120.6 (3) |
N8—C7—C2 | 118.90 (16) | C16—C17—H17 | 121 (2) |
C9—N8—C7 | 128.23 (18) | C18—C17—H17 | 119 (3) |
C9—N8—H8 | 116 (2) | C13—C18—C17 | 119.9 (3) |
C7—N8—H8 | 116 (2) | C13—C18—H18 | 123.9 (17) |
O10—C9—N8 | 125.6 (2) | C17—C18—H18 | 116.2 (17) |
O10—C9—C11 | 117.95 (19) | ||
O1—C1—C2—C3 | 170.9 (2) | C7—N8—C9—O10 | −3.3 (4) |
C13—C1—C2—C3 | −6.2 (3) | C7—N8—C9—C11 | 178.0 (2) |
O1—C1—C2—C7 | −8.3 (3) | O10—C9—C11—Cl12 | 176.4 (2) |
C13—C1—C2—C7 | 174.60 (18) | N8—C9—C11—Cl12 | −4.8 (3) |
C7—C2—C3—C4 | −0.6 (3) | O1—C1—C13—C14 | 114.9 (2) |
C1—C2—C3—C4 | −179.76 (19) | C2—C1—C13—C14 | −67.8 (3) |
C2—C3—C4—C5 | 0.1 (3) | O1—C1—C13—C18 | −56.9 (3) |
C2—C3—C4—Cl4 | −179.37 (15) | C2—C1—C13—C18 | 120.4 (2) |
C3—C4—C5—C6 | 0.4 (4) | C18—C13—C14—C15 | −0.2 (3) |
Cl4—C4—C5—C6 | 179.89 (18) | C1—C13—C14—C15 | −171.9 (2) |
C4—C5—C6—C7 | −0.5 (4) | C18—C13—C14—Cl14 | 176.90 (18) |
C5—C6—C7—N8 | −178.2 (2) | C1—C13—C14—Cl14 | 5.2 (3) |
C5—C6—C7—C2 | 0.1 (3) | C13—C14—C15—C16 | −0.4 (3) |
C3—C2—C7—C6 | 0.4 (3) | Cl14—C14—C15—C16 | −177.56 (19) |
C1—C2—C7—C6 | 179.63 (19) | C14—C15—C16—C17 | 0.5 (4) |
C3—C2—C7—N8 | 178.80 (18) | C15—C16—C17—C18 | 0.1 (5) |
C1—C2—C7—N8 | −2.0 (3) | C14—C13—C18—C17 | 0.7 (4) |
C6—C7—N8—C9 | −5.3 (3) | C1—C13—C18—C17 | 172.9 (2) |
C2—C7—N8—C9 | 176.4 (2) | C16—C17—C18—C13 | −0.7 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
N8—H8···O1 | 0.84 (3) | 1.95 (3) | 2.634 (2) | 138 (3) |
C6—H6···Cl14i | 0.94 (3) | 2.87 (3) | 3.675 (2) | 143 (2) |
C11—H11B···O10ii | 0.93 (3) | 2.50 (3) | 3.320 (3) | 147 (2) |
C18—H18···Cl14iii | 0.95 (3) | 2.84 (3) | 3.745 (3) | 161 (2) |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x, −y+2, −z+2; (iii) x−1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C15H10Cl3NO2 |
Mr | 342.59 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 295 |
a, b, c (Å) | 7.5776 (9), 10.1565 (10), 10.7862 (12) |
α, β, γ (°) | 70.069 (8), 77.604 (9), 70.388 (8) |
V (Å3) | 730.47 (14) |
Z | 2 |
Radiation type | Cu Kα |
µ (mm−1) | 5.71 |
Crystal size (mm) | 0.35 × 0.2 × 0.2 |
Data collection | |
Diffractometer | Oxford Diffraction SuperNova (single source at offset) Atlas |
Absorption correction | Multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) |
Tmin, Tmax | 0.117, 0.319 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5245, 2917, 2610 |
Rint | 0.017 |
(sin θ/λ)max (Å−1) | 0.627 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.043, 0.113, 1.05 |
No. of reflections | 2917 |
No. of parameters | 230 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.37, −0.44 |
Computer programs: CrysAlis PRO (Oxford Diffraction, 2009), SIR92 (Altomare et al., 1993), SHELXL97 (Sheldrick, 2008), Stereochemical Workstation Operation Manual (Siemens, 1989).
D—H···A | D—H | H···A | D···A | D—H···A |
N8—H8···O1 | 0.84 (3) | 1.95 (3) | 2.634 (2) | 138 (3) |
C6—H6···Cl14i | 0.94 (3) | 2.87 (3) | 3.675 (2) | 143 (2) |
C11—H11B···O10ii | 0.93 (3) | 2.50 (3) | 3.320 (3) | 147 (2) |
C18—H18···Cl14iii | 0.95 (3) | 2.84 (3) | 3.745 (3) | 161 (2) |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x, −y+2, −z+2; (iii) x−1, y, z. |
Acknowledgements
BPS thanks R. L. FineChem, Bangalore, India, for the gift of a sample of the title compound.
References
Allen, F. H. (2002). Acta Cryst. B58, 380–388. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343–350. CrossRef Web of Science IUCr Journals Google Scholar
Evans, D., Cracknell, M. E., Saunders, J. C., Smith, C. E., Willamson, W. R. N., Dowson, W. & Sweatman, W. J. F. (1987). J. Med. Chem. 30, 1321–1327. CrossRef CAS PubMed Web of Science Google Scholar
Kálmán, A., Argay, G., Scharfenberg-Pfeiffer, D., Höhne, E. & Ribár, B. (1991). Acta Cryst. B47, 68–77. CSD CrossRef IUCr Journals Google Scholar
Kubicki, M. & Szafrański, M. (1998). J. Mol. Struct. 446, 1–9. Web of Science CSD CrossRef CAS Google Scholar
Malathy Sony, S. M., Charles, P., Ponnuswamy, M. N. & Nethaji, M. (2005). Acta Cryst. E61, o632–o634. Web of Science CrossRef IUCr Journals Google Scholar
Oxford Diffraction (2009). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England. Google Scholar
Prasanna, M. D. & Guru Row, T. N. (2000). CrystEngComm, 2, 134–140. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Siemens (1989). Stereochemical Workstation Operation Manual. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA. Google Scholar
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Benzophenone and related compounds have been reported to act as e.g., antiallergic, anti-inflammatory, antiasthmatic, antimalarial, anti-microbial and antianaphylactic agents (Evans et al., 1987). Here we report the crystal structure of 2-chloroacetamido-5-chloro-2'-chlorobenzophenone (alternative name: 2-chloro-N-{4-chloro-2-[(2-chlorophenyl)carbonyl]phenyl}acetamide; 1, Scheme 1), which is an intermediate in the synthesis of certain anxiolytic, anticonvulsant and sedative drugs, and is also a starting material for the synthesis of diazepam and other benzodiazepines.
The structure of 1 is isostructural with the previously described 2-chloroacetamido-5-chloro-2'-fluorobenzophenone derivative (Prasanna & Guru Row, 2000). Both compounds crystallize in the triclinic P-1 space group, and the unit cell dimensions are similar. Also the positions of the atoms in the unit cell are similar, after applying the transformation (index 1 refers to Prasanna & Guru Row, 2 - to the present structure): x2=x1+0.5, y2=y1+0.5, z2=z1+1.5. The isostructurality index (Kálmán et al., 1991), which describes the differences between the positions of the atoms in the unit cell has the value of 97.4% (for perfect isostructurality it should be 100%). Kubicki & Szafrański (1998) proposed the modification of this latter parameter which takes into account the point group symmetry and gives more absolute measure of the degree of isostructurality: it should be 1 for ideally isomorphous compounds and 0 for randomly distributed atoms. The value of this modified index is 0.94.
The conformation of 1 (Fig. 1) might be described by dihedral angles between four approximately planar fragments: acetamide [A, planar within 0.0065 (19) Å, with Cl2 atom significantly, by 0.110 (5)Å out of the plane], central phenyl [B, maximum deviation 0.0034 (14) Å], bridging carbonyl group C—C(=O)-C [C, max. deviation 0.015 (2) Å], and terminal phenyl [D, 0.0045 (19) Å]. The first three are close to coplanarity, the dihedral angles are A/B 7.06 (11)° and B/C 7.17 (12)°. Such a coplanar conformation of phenyl and carbonyl plane is quite uncommon for benzophenones, in a majority of the compounds found in the CSD (Allen, 2002) both phenyl rings are almost equally, and significantly, twisted with respect to the central plane. In the case of 1, as in some similar cases (for instance in the isostructural 2'-fluoro derivative but also in two crystal forms of 2-chloroacetamido-5-chlorobenzophenone (monoclinic: Prasanna & Guru Row, 2000, and triclinic: Malathy Sony et al., 2005), the factor responsible for such a coplanar conformation is the intramolecular hydrogen bond N—H···O (cf. Table 1). This hydrogen bond closes the six-membered ring, planar within 0.072 (7) Å. The second phenyl ring, which has no factor that can stabilize coplanar conformation, is typically, by 62.14 (10)°, twisted with respect to the bridge. The Cl atom of chloroacetamide group is anti with respect to the oxygen atom [O10—C9—C11—Cl12 torsion angle of 176.4 (2)°] and syn with respect to the N atom [N8—C9—C11—Cl12 is -4.8 (3)°]
In the crystal structure there are some weak C—H···O and C—H···Cl interactions, which might be of some importance when the strong hydrogen bond donor is involved in intramolecular interaction (Fig. 2)