Crystal structure of 2-(4-chloro-phen-yl)-2-oxoethyl 3-bromo-benzoate.

2-(4-Chloro-phen-yl)-2-oxoethyl 3-bromo-benzoate, C15H10BrClO3, was synthesized in a single-step reaction by condensation of 3-bromo-benzoic acid with 2-bromo-1-(4-chloro-phen-yl)ethanone in di-methyl-formamide in the presence of tri-ethyl-amine as a catalyst. The structure consists of an aryl ketone moiety linked to an aryl ester unit by a methyl-ene group. Both units are reasonably planar (r.m.s. deviations of 0.119 and 0.010 Å for the aryl ketone and aryl ester units, respectively) and are almost orthogonal, with an angle of 88.60 (3)° between them. In the crystal, mol-ecules form five separate sets of inversion dimers. Three of these are generated by two C-H⋯O inter-actions and a C-H⋯Br contact, and form chains along c and along the ab cell diagonal. In addition, two inversion-related π-π stacking inter-actions between like aryl rings again form chains of mol-ecules but in this instance along the bc diagonal. These contacts generate infinite layers of mol-ecules parallel to (011) and stack the mol-ecules along the a-axis direction.

Chemical context

Keto esters, an important class of versatile inter­mediates, have been reported to show anti­tumor activity against Ehrlich cells and HeLa cells (Kinoshita & Umezawa, 1960 ▶). They also regulate the flowering times of some plants (Kai et al., 2007 ▶). Recent studies have revealed that they also exhibit inhibitory activity against two isozymes of 11β-hy­droxy­steroid de­hydro­genases (11β-HSD1 and 11β-HSD2), which catalyse the inter­conversion of active cortisol and inactive cortisone (Zhang et al., 2009 ▶). Dicarbonyl compounds and their deriv­atives are also among the most versatile and frequently employed synthons in organic synthesis, especially in heterocyclic chemistry (Stanovnik & Svete, 2004 ▶; Sheibani et al., 2006a ▶,b ▶, 2007 ▶; Pal et al., 2008 ▶). In this work, we report the synthesis of 2-(4-chloro­phen­yl)-2-oxoethyl 3-bromo­benzoate, (1), which may be used as an effective synthon in organic chemistry.

Structural commentary

The structure of (1) consists of an aryl ketone moiety linked to an aryl ester unit by the C8 methyl­ene group and both groupings are reasonably planar. There is an r.m.s. deviation of 0.119 Å from the best-fit plane through atoms Br1, C1–C8, O1, O2 [maximum deviation 0.2477 (11) Å for O1] while the plane of the carboxyl­ate unit subtends an angle of 15.5 (2)° to that of the bromo­benzene ring. In addition, the plane of the aryl ketone unit C8–C15, O3, Cl1 has an r.m.s. deviation of 0.010 Å [maximum deviation 0.0171 (15) Å for C15]. The aryl ketone and aryl ester planes are almost orthogonal with an angle of 88.61 (3)° between them. Bond lengths and angles in the mol­ecule are normal and are generally similar to those found in closely related mol­ecules (see for example Fun et al., 2011a ▶; Chidan Kumar et al., 2014c ▶).

Supra­molecular features

In the crystal structure, each mol­ecule forms five separate inversion dimers. C8—H8B⋯O1 and C15—H15 O3 hydrogen bonds each generate (10) rings, forming zigzag chains along c. Additional C4—H4⋯Br1 contacts also form inversion dimers with (8) rings and these combine with the C8—H8B⋯O1 contacts to link alternating pairs of dimers into infinite chains approximately along the ab cell diagonal, Table 1 ▶, Fig. 2 ▶. Inter­estingly, infinite chains of alternating inversion dimers also result from a pair of π–π stacking inter­actions between adjacent 3-bromo­phenyl rings, Cg1⋯Cg1iv = 3.6987 (10) Å, and neighbouring 4-chloro­phenyl rings Cg2⋯Cg2v = 3.8585 (11) Å, in this case along the bc diagonal, Fig. 3 ▶ [Cg1 and Cg2 are the centroids of the C1–C6 and C10–C15 rings, respectively; symmetry codes (iv) −x, 2 − y, −z; (v) 2 − x, 1 − y, 1 − z]. These contacts combine to generate extended layers of mol­ecules parallel to (011), Fig. 4 ▶, and to stack mol­ecules along the a-axis direction, Fig. 5 ▶.

Table 1

Hydrogen-bond geometry (, )

DHA	DH	HA	D A	DHA
C4H4Br1i	0.95	2.97	3.8762(18)	160
C8H8BO1ii	0.99	2.42	3.396(2)	168
C15H15O3iii	0.95	2.60	3.418(2)	144

Symmetry codes: (i) ; (ii) ; (iii) .

Figure 2

Chains of linked inversion dimers generated by C—H⋯O and C—H⋯Br hydrogen bonds, drawn as dashed lines.

Figure 3

A chain of inversion dimers generated by π–π contacts, dotted green lines, between 3-bromo­phenyl and 4-chloro­phenyl rings. Ring centroids are displayed as coloured spheres.

Figure 4

Overall packing of (1) viewed at right angles to (011).

Figure 5

Overall packing of (1) viewed along the a-axis direction.

Database survey

A search of the Cambridge Crystallographic Database (Groom & Allen, 2014 ▶) reveals only eight structures with the 2-oxo-2-phenyl­ethyl benzoate skeleton. These include the archetypal 2-oxo-2-phenyl­ethyl benzoate (Fun et al., 2011a ▶), three additional 2-(4-chloro­phen­yl)-2-oxoethyl derivatives (Fun et al., 2011 Chidan Kumar et al., 2014a ▶,b ▶) and the corresponding compound 2-(4-bromo­phen­yl)-2-oxoethyl 3-chloro­benzoate with the chloro- and bromo-substituents reversed (Chidan Kumar et al., 2014c ▶). Interestingly, inversion-dimer formation is a feature of the packing in several of these structures.

Synthesis and crystallization

The preparation followed a procedure developed for the preparation of a related compound (Khan et al., 2012 ▶). Tri­ethyl­amine (4–5 drops) was added at room temperature to a stirred solution of 3-bromo­benzoic acid (1.0 mmol) in N,N-di­methyl­formamide (DMF), followed by a solution of 2-bromo-1-(4-chloro­phen­yl)ethanone (1.0 mmol). The reaction mixture was stirred for 2 h. Progress of the reaction was monitored by TLC. After completion, the mixture was poured into water and the precipitated solid was filtered, dried and recrystallized (EtOAc/hexa­ne) to afford 2-(4-chloro­phen­yl)-2-oxoethyl 3-bromo­benzoate (1). The formation of keto ester (3) was indicated by the appearance of two typical stretching vibrations ν(C=O) ester (1724) and ν(C=O) keto (1698) cm−1, respectively and the disappearance of characteristic IR stretching absorptions ascribable to the carb­oxy­lic acid group in the region of 3400–2400 cm−1. In the 1H NMR spectrum, the signals for the aromatic protons appeared in their respective regions and the disappearance of a characteristic signal for the COOH proton confirmed the formation of the title compound (1). The 13C NMR spectrum displayed two characteristic signals for the keto and ester carbonyl carbon atoms at 190.7 and 165.3 p.p.m., respectively. Yield: 88%; m.p. 372–373 K; R f: 0.72 (10% EtOAc/hexa­ne); IR (ATR, cm−1): 3089 (Csp 2-H), 2933, 2856 (Csp 3-H), 1724 (C=O ester), 1698 (C=O ketone), 1585, 1479 (C=C Ar), 1225 (C—O); 1H NMR (300 MHz, CDCl3): δ 8.06–8.03 (m, 1H, Ar-H), 7.94–7.90 (m, 2H, Ar-H), 7.73–7.70 (m, 1H, Ar-H), 7.52–7.48 (m, 2H, Ar-H), 7.46–7.36 (m, 2H, Ar-H), 5.57 (s, 2H, CH2); 13C NMR (75 MHz, CDCl3): δ 190.7, 165.3, 140.6, 134.5, 133.1, 132.4, 132.0, 131.0, 129.3, 129.3, 127.3, 122.1, 66.5.

Refinement

All H atoms were refined using a riding model, with C—H = 0.95 Å and U iso(H) = 1.2U eq(C) for aromatic, and C—H = 0.99 Å and U iso(H) = 1.2U eq(C) for the methyl­ene H atoms.

Crystal structure: contains datablock(s) global, 1. DOI: 10.1107/S1600536814021643/hg5410sup1.cif

Structure factors: contains datablock(s) 1. DOI: 10.1107/S1600536814021643/hg54101sup2.hkl

CCDC reference: 864789

Additional supporting information: crystallographic information; 3D view; checkCIF report

C15H10BrClO3	Z = 2
Mr = 353.59	F(000) = 352
Triclinic, P1	Dx = 1.708 Mg m−3
a = 6.6797 (3) Å	Mo Kα radiation, λ = 0.71073 Å
b = 10.0238 (4) Å	Cell parameters from 6648 reflections
c = 10.7851 (5) Å	θ = 3.2–29.2°
α = 90.980 (4)°	µ = 3.19 mm−1
β = 107.573 (4)°	T = 130 K
γ = 92.138 (3)°	Block, colourless
V = 687.64 (5) Å3	0.50 × 0.40 × 0.20 mm

Agilent SuperNova (Dual, Cu at zero, Atlas CCD) diffractometer	3327 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	3062 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.033
ω scans	θmax = 29.2°, θmin = 3.2°
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	h = −8→8
Tmin = 0.505, Tmax = 1.000	k = −13→13
10822 measured reflections	l = −14→14

Refinement on F2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.027	H-atom parameters constrained
wR(F2) = 0.064	w = 1/[σ2(Fo2) + (0.0307P)2 + 0.1071P] where P = (Fo2 + 2Fc2)/3
S = 1.05	(Δ/σ)max = 0.001
3327 reflections	Δρmax = 0.35 e Å−3
181 parameters	Δρmin = −0.60 e Å−3

Experimental. Absorption correction: CrysAlisPro, Agilent (2011), Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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.

	x	y	z	Uiso*/Ueq
C1	0.1452 (3)	0.76183 (16)	0.09834 (16)	0.0153 (3)
C2	−0.0463 (3)	0.73719 (17)	0.00240 (16)	0.0165 (3)
H2	−0.0671	0.6625	−0.0562	0.020*
C3	−0.2052 (3)	0.82374 (17)	−0.00564 (16)	0.0164 (3)
C4	−0.1816 (3)	0.93075 (18)	0.08011 (17)	0.0200 (4)
H4	−0.2944	0.9879	0.0739	0.024*
C5	0.0097 (3)	0.95371 (18)	0.17577 (17)	0.0213 (4)
H5	0.0280	1.0271	0.2356	0.026*
C6	0.1742 (3)	0.87044 (17)	0.18485 (17)	0.0189 (3)
H6	0.3057	0.8874	0.2496	0.023*
C7	0.3120 (3)	0.66531 (17)	0.10555 (16)	0.0169 (3)
C8	0.6639 (3)	0.62000 (17)	0.20718 (17)	0.0182 (3)
H8A	0.8031	0.6678	0.2388	0.022*
H8B	0.6573	0.5687	0.1266	0.022*
C9	0.6368 (3)	0.52539 (17)	0.30950 (16)	0.0176 (3)
C10	0.8001 (3)	0.42573 (17)	0.35889 (16)	0.0166 (3)
C11	0.9739 (3)	0.41710 (18)	0.31370 (17)	0.0201 (4)
H11	0.9919	0.4770	0.2502	0.024*
C12	1.1213 (3)	0.32135 (19)	0.36109 (18)	0.0231 (4)
H12	1.2400	0.3152	0.3305	0.028*
C13	1.0919 (3)	0.23586 (18)	0.45295 (18)	0.0229 (4)
C14	0.9204 (3)	0.24247 (19)	0.49972 (18)	0.0242 (4)
H14	0.9029	0.1821	0.5630	0.029*
C15	0.7757 (3)	0.33824 (19)	0.45280 (17)	0.0215 (4)
H15	0.6584	0.3446	0.4848	0.026*
O1	0.28187 (18)	0.55756 (12)	0.05094 (12)	0.0222 (3)
O2	0.50195 (18)	0.71409 (12)	0.17991 (12)	0.0186 (3)
O3	0.48450 (19)	0.53074 (14)	0.34811 (13)	0.0257 (3)
Cl1	1.27582 (8)	0.11559 (5)	0.51284 (5)	0.03372 (13)
Br1	−0.46435 (2)	0.79269 (2)	−0.13927 (2)	0.02456 (7)

	U11	U22	U33	U12	U13	U23
C1	0.0181 (8)	0.0132 (8)	0.0156 (8)	0.0008 (6)	0.0067 (7)	0.0013 (6)
C2	0.0189 (8)	0.0136 (8)	0.0178 (8)	−0.0008 (6)	0.0069 (7)	−0.0010 (6)
C3	0.0165 (8)	0.0160 (9)	0.0160 (8)	−0.0002 (6)	0.0039 (7)	0.0007 (6)
C4	0.0244 (9)	0.0160 (9)	0.0213 (9)	0.0033 (7)	0.0091 (7)	−0.0003 (7)
C5	0.0288 (9)	0.0157 (9)	0.0196 (9)	0.0016 (7)	0.0078 (8)	−0.0043 (7)
C6	0.0219 (8)	0.0167 (9)	0.0164 (8)	−0.0014 (7)	0.0035 (7)	−0.0012 (6)
C7	0.0166 (8)	0.0178 (9)	0.0159 (8)	−0.0010 (6)	0.0043 (7)	0.0009 (6)
C8	0.0159 (8)	0.0179 (9)	0.0206 (9)	0.0023 (6)	0.0049 (7)	−0.0008 (7)
C9	0.0181 (8)	0.0192 (9)	0.0142 (8)	−0.0007 (6)	0.0035 (7)	−0.0043 (6)
C10	0.0179 (8)	0.0154 (9)	0.0144 (8)	−0.0023 (6)	0.0021 (7)	−0.0035 (6)
C11	0.0217 (8)	0.0187 (9)	0.0204 (9)	0.0004 (7)	0.0071 (7)	−0.0001 (7)
C12	0.0187 (8)	0.0241 (10)	0.0256 (10)	0.0009 (7)	0.0055 (8)	−0.0029 (7)
C13	0.0258 (9)	0.0169 (9)	0.0188 (9)	0.0036 (7)	−0.0041 (7)	−0.0050 (7)
C14	0.0314 (10)	0.0206 (10)	0.0181 (9)	−0.0022 (7)	0.0037 (8)	0.0015 (7)
C15	0.0227 (9)	0.0238 (10)	0.0174 (9)	−0.0021 (7)	0.0058 (7)	−0.0024 (7)
O1	0.0204 (6)	0.0167 (7)	0.0272 (7)	0.0018 (5)	0.0043 (5)	−0.0065 (5)
O2	0.0154 (6)	0.0162 (6)	0.0218 (6)	0.0014 (5)	0.0019 (5)	−0.0017 (5)
O3	0.0224 (6)	0.0325 (8)	0.0262 (7)	0.0046 (5)	0.0127 (6)	0.0037 (6)
Cl1	0.0352 (3)	0.0251 (3)	0.0316 (3)	0.0110 (2)	−0.0049 (2)	−0.0012 (2)
Br1	0.01750 (10)	0.02591 (12)	0.02626 (12)	0.00457 (7)	0.00057 (8)	−0.00652 (8)

C1—C6	1.391 (2)	C8—H8A	0.9900
C1—C2	1.391 (2)	C8—H8B	0.9900
C1—C7	1.488 (2)	C9—O3	1.212 (2)
C2—C3	1.380 (2)	C9—C10	1.490 (2)
C2—H2	0.9500	C10—C11	1.393 (2)
C3—C4	1.377 (2)	C10—C15	1.393 (2)
C3—Br1	1.8995 (16)	C11—C12	1.391 (2)
C4—C5	1.387 (3)	C11—H11	0.9500
C4—H4	0.9500	C12—C13	1.374 (3)
C5—C6	1.386 (2)	C12—H12	0.9500
C5—H5	0.9500	C13—C14	1.387 (3)
C6—H6	0.9500	C13—Cl1	1.7429 (18)
C7—O1	1.202 (2)	C14—C15	1.379 (3)
C7—O2	1.348 (2)	C14—H14	0.9500
C8—O2	1.4283 (19)	C15—H15	0.9500
C8—C9	1.515 (2)
C6—C1—C2	120.59 (15)	C9—C8—H8B	109.7
C6—C1—C7	122.35 (15)	H8A—C8—H8B	108.2
C2—C1—C7	117.04 (15)	O3—C9—C10	121.67 (15)
C3—C2—C1	118.46 (16)	O3—C9—C8	120.25 (15)
C3—C2—H2	120.8	C10—C9—C8	118.08 (14)
C1—C2—H2	120.8	C11—C10—C15	119.46 (16)
C4—C3—C2	122.08 (16)	C11—C10—C9	122.21 (15)
C4—C3—Br1	119.44 (13)	C15—C10—C9	118.33 (15)
C2—C3—Br1	118.49 (13)	C12—C11—C10	120.38 (16)
C3—C4—C5	118.85 (16)	C12—C11—H11	119.8
C3—C4—H4	120.6	C10—C11—H11	119.8
C5—C4—H4	120.6	C13—C12—C11	118.76 (17)
C6—C5—C4	120.58 (17)	C13—C12—H12	120.6
C6—C5—H5	119.7	C11—C12—H12	120.6
C4—C5—H5	119.7	C12—C13—C14	122.01 (17)
C5—C6—C1	119.41 (16)	C12—C13—Cl1	119.05 (15)
C5—C6—H6	120.3	C14—C13—Cl1	118.94 (14)
C1—C6—H6	120.3	C15—C14—C13	118.85 (17)
O1—C7—O2	124.03 (15)	C15—C14—H14	120.6
O1—C7—C1	124.27 (15)	C13—C14—H14	120.6
O2—C7—C1	111.69 (15)	C14—C15—C10	120.54 (17)
O2—C8—C9	109.80 (13)	C14—C15—H15	119.7
O2—C8—H8A	109.7	C10—C15—H15	119.7
C9—C8—H8A	109.7	C7—O2—C8	114.81 (13)
O2—C8—H8B	109.7
C6—C1—C2—C3	0.7 (2)	C8—C9—C10—C11	−0.3 (2)
C7—C1—C2—C3	179.07 (14)	O3—C9—C10—C15	−0.7 (3)
C1—C2—C3—C4	−1.8 (2)	C8—C9—C10—C15	−179.85 (16)
C1—C2—C3—Br1	178.47 (11)	C15—C10—C11—C12	0.5 (3)
C2—C3—C4—C5	1.4 (3)	C9—C10—C11—C12	−179.10 (16)
Br1—C3—C4—C5	−178.85 (12)	C10—C11—C12—C13	0.0 (3)
C3—C4—C5—C6	0.1 (3)	C11—C12—C13—C14	−0.1 (3)
C4—C5—C6—C1	−1.1 (3)	C11—C12—C13—Cl1	180.00 (14)
C2—C1—C6—C5	0.7 (2)	C12—C13—C14—C15	−0.3 (3)
C7—C1—C6—C5	−177.59 (15)	Cl1—C13—C14—C15	179.61 (14)
C6—C1—C7—O1	164.73 (17)	C13—C14—C15—C10	0.8 (3)
C2—C1—C7—O1	−13.6 (2)	C11—C10—C15—C14	−0.9 (3)
C6—C1—C7—O2	−15.9 (2)	C9—C10—C15—C14	178.71 (16)
C2—C1—C7—O2	165.76 (13)	O1—C7—O2—C8	−9.5 (2)
O2—C8—C9—O3	5.4 (2)	C1—C7—O2—C8	171.15 (13)
O2—C8—C9—C10	−175.45 (14)	C9—C8—O2—C7	−75.86 (17)
O3—C9—C10—C11	178.89 (17)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···Br1i	0.95	2.97	3.8762 (18)	160
C8—H8B···O1ii	0.99	2.42	3.396 (2)	168
C15—H15···O3iii	0.95	2.60	3.418 (2)	144

Table 2

Experimental details

Crystal data
Chemical formula	C15H10BrClO3
M r	353.59
Crystal system, space group	Triclinic, P
Temperature (K)	130
a, b, c ()	6.6797(3), 10.0238(4), 10.7851(5)
, , ()	90.980(4), 107.573(4), 92.138(3)
V (3)	687.64(5)
Z	2
Radiation type	Mo K
(mm1)	3.19
Crystal size (mm)	0.50 0.40 0.20
Data collection
Diffractometer	Agilent SuperNova (Dual, Cu at zero, Atlas CCD)
Absorption correction	Multi-scan (CrysAlis PRO; Agilent, 2011 ▶)
T min, T max	0.505, 1.000
No. of measured, independent and observed [I > 2(I)] reflections	10822, 3327, 3062
R int	0.033
(sin /)max (1)	0.687
Refinement
R[F 2 > 2(F 2)], wR(F 2), S	0.027, 0.064, 1.05
No. of reflections	3327
No. of parameters	181
H-atom treatment	H-atom parameters constrained
max, min (e 3)	0.35, 0.60

Computer programs: CrysAlis PRO, (Agilent, 2011 ▶), SHELXS97 and SHELXL2014 (Sheldrick, 2008 ▶), Mercury (Macrae et al., 2008 ▶), enCIFer (Allen et al., 2004 ▶), PLATON (Spek, 2009 ▶) and publCIF (Westrip, 2010 ▶).