(4- chlorophenyl)methanone

ANALYTICAL SCIENCES 2006, VOL. 22 2006 © The Japan Society for Analytical Chemistry

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Synthesis and Crystal Structure of (5-Chloro-2-hydroxyphenyl)-(4chlorophenyl)methanone Venu T. DEVAIAH,* S. NAVEEN,** S. SHASHIKANTH,* Sridhar M. ANANDALWAR,**† Javaregowda S. PRASAD** *Department of Studies in Chemistry, University of Mysore, Mysore 570 006, India **Department of Studies in Physics, University of Mysore, Mysore 570 006, India

The title compound, C13H8Cl2O2, was synthesized and the structure was investigated by X-ray methods. The compound crystallizes in triclinic crystal class in the space group P1 with cell parameters a = 7.3010(8)Å, b = 7.3510(8)Å, c = 10.9240(14)Å, α = 87.976(6)˚, β = 85.903(7)˚, γ = 84.736(8)˚, Z = 2. The structure exhibits intramolecular hydrogen bond of the type O–H·O. (Received January 23, 2006; Accepted April 14, 2006; Published on web July 14, 2006)

Benzophenones have a wide variety of applications as biologically active compounds, such as anti-inflammatory, anticancer, anti-asthmatic, anti-malarial, anti-mitotic,1 anti-fungal Further, these analogues are and anti-bacterial2 agents. evaluated as inhibitors of HIV reverse transcriptase (RT) and for the growth of MT-4 cells. In addition, they find a place in industrial chemistry, and are widely used in sunscreen lotions. In light of the above observations, the title compound was synthesized and its crystal structure is reported here. In a typical procedure, 4-chlorophenyl-4-chlorobenzoate (10 g, 0.039 mol) was thoroughly mixed with montmorillonite K10 clay (1:3 w/w) in the solid state using a vortex mixer and subjected to microwave irradiation at 40% power for 5 min. Completion of the reaction was monitored on TLC and the product was extracted into dichloromethane (3 × 10 ml). The organic layer was dried over anhydrous sodium sulfate and evaporated to dryness to obtain a crude solid, which upon recrystallization with ethanol gave yellow crystals with 87% yield. A schematic diagram of the molecule is shown in Fig. 1. A single crystal of the title compound with dimensions of 0.2 × 0.3 × 0.3 mm was chosen for an X-ray diffraction study. The data were collected at room temperature on a DIPLabo Image Plate system with graphite-monochromated radiation (Mo Kα). Each exposure of the image plate was set to a period of 400 s. Thirty six frames of data were collected in the oscillation mode with an oscillation range of 5˚, and processed using Denzo.3 The reflections were merged with Scalepack. All of the frames

Fig. 1 †

Schematic diagram.

To whom correspondence should be addressed. E-mail: [email protected]

could be indexed using a primitive triclinic lattice. The structure was solved by direct methods using SHELXS-97. The crystal and experimental details are given in Table 1. All of the non-hydrogen atoms were revealed in the first fourier map. They were refined anisotropically before the hydrogen atoms were fixed. The hydrogen atoms were fixed at chemically accpetable positions, and were allowed to ride on their parent atoms. Refinement was carried out using 3329 reflections & 155 parameters using SHELXL-97. The residuals converged to R = 0.0545. Table 2 gives the selected bond

Table 1

Crystal ata and structure refinement table

Volume Reflections collected Data/parameters Dc Absorption coefficient θmax R (∆ /σ )max (∆ρ)max (∆ρ)min Refinement method Measurement Program system Structure determination Refinement

C13H8Cl2O2 267.09 293(2)K 0.71073 Å triclinic Z=2 P1 a = 7.3010(8)Å b = 7.3510(8)Å c = 10.9240(14)Å α = 87.976(6)˚ β = 85.903(7)˚ γ = 84.736(8)˚ 582.08(12)Å3 4768 3329/155 1.524 Mg/m3 0.541 mm–1 32.48˚ 0.0545 0.000 0.359 eÅ–3 –0.300 eÅ–3 full-matrix least-squares on F2 DIPLabo Denzo SHELXS-97 SHELXL-97

CCDC

600820

Empirical formula Formula weight Temperature Wavelength Crystal system Space group Cell dimensions

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Table 2

Selected bond lengths (Å) and bond angles (˚)

characterized by the torsion angles relative to the carbonyl plane. Another indicator of conformation are the values of the torsion angles C4–C5–C8–O9 = –38.4(3)˚ and O9–C8–C10–C11 = –13.5(6)˚. For benzophenones, these torsion angles take the same sign, and are each reported to be 30˚ in energy minimized benzophenone.5 The structure exhibits intramolecular hydrogen bonding of the type O–H·O. The intramolecular hydrogen bonding O16–H16·O9 is between the carbonyl group at C8 and the hydroxy group at C11 with a length of 2.567(2)Å, and the angle being 145˚. This O–H·O angle of 145˚ compares well with the one reported for (2-hydroxy-5-methylphenyl)-(2bromophenyl)methanone6 which has a length of 2.595(6)Å and the corresponding angle being 145˚. The molecules when viewed down the a axis appear to be stacked.

Acknowledgements The authors would like to express their thanks to DST, Government of India, for financial assistance under the project SP/I2/FOO/93.

References

Fig. 2

ORTEP drawing of the molecule at 50% probability.

lengths and bond angles, which are in good agreement with the standard values. An ORTEP diagram of the molecule at 50% probability is shown in Fig. 2. The molecule is non-planar. The two phenyl rings are bridged via a carbonyl group. The bond lengths and bond angles are normal and the molecular conformation is characterized by a dihedral angle of 52.15(9)˚ between the mean planes of the two aromatic rings which is comparable with a corresponding value of 54.39(8)˚ observed in 2-methylamino-5chlorobenzophenone.4 The rotation of the aromatic rings is

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