2-Oxo-4-trifluoro­meth­yl-2H-chromen-7-yl 2-bromo-2-methyl­propano­ate

N Haridharan; V Ramkumar; R Dhamodharan

doi:10.1107/S1600536810020234

. 2010 Jun 9;66(Pt 7):o1606. doi: 10.1107/S1600536810020234

2-Oxo-4-trifluoromethyl-2H-chromen-7-yl 2-bromo-2-methylpropanoate

N Haridharan ^a, V Ramkumar ^a, R Dhamodharan ^a,^*

PMCID: PMC3006816 PMID: 21587840

Abstract

In the title compound, C₁₄H₁₀BrF₃O₄, the coumarin ring system is almost plannar (r.m.s. deviation = 0.025 Å) and a short C—H⋯F contact occurs. The propanoate fragment is orientated almost perpendicular to the ring [dihedral angle = 71.80 (12)°]. In the crystal, molecules are linked by C—H⋯O hydrogen bonds, generating [100] chains.

Related literature

For the applications of the title compound in polymer chemistry, see: Sinkel et al. (2008 ▶); Matyjaszewski et al. (2008 ▶); Stenzel-Rosenbaum et al. (2001 ▶).

Experimental

Crystal data

C₁₄H₁₀BrF₃O₄
M _r = 379.13
Triclinic,
a = 6.1842 (4) Å
b = 11.0297 (6) Å
c = 11.0619 (7) Å
α = 99.982 (2)°
β = 91.797 (2)°
γ = 104.387 (2)°
V = 717.61 (8) Å³
Z = 2
Mo Kα radiation
μ = 2.91 mm⁻¹
T = 298 K
0.40 × 0.26 × 0.24 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.389, T _max = 0.542
9951 measured reflections
3796 independent reflections
2390 reflections with I > 2σ(I)
R _int = 0.022

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.109
S = 1.01
3796 reflections
201 parameters
H-atom parameters constrained
Δρ_max = 0.78 e Å⁻³
Δρ_min = −0.85 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT-Plus (Bruker, 2004 ▶); data reduction: SAINT-Plus and XPREP (Bruker, 2004 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810020234/hb5450sup1.cif

e-66-o1606-sup1.cif^{(17.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810020234/hb5450Isup2.hkl

e-66-o1606-Isup2.hkl^{(186.1KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯F2	0.93	2.47	3.019 (3)	118
C6—H6⋯O4ⁱ	0.93	2.52	3.261 (4)	136

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors acknowledge the Department of Chemistry, IIT Madras, for the X-ray data collection.

supplementary crystallographic information

Comment

The title compound C₁₄H₁₀BrF₃O₄, is a monofunctional coumarin derivative, which is used as an initiator (Sinkelet al. 2008) in Atom Transfer Radical Polymerization (ATRP). Being a monofunctional unit it can form end-functionalized linear polymers (Matyjaszewski et al. 2008; Stenzel-Rosenbaum et al.2001) when used as an initiator. Since most of the synthesized functionalized initiators are characterized by other techniques, their single crystal XRD reports are few.

The title compound is one such successful ATRP initiator which was crystallised from chloroform. It contains coumarin derivative with bromo methyl propanoate. The coumarin moiety is an important oxygen containing heterocyclic compound with diverse bioactivities such as non peptidic HIV protease inhibition and tyrosine kinase inhibition. Owing to such interesting properties, the synthesis of coumarin based initiators and their crystal structures are worth while to study.

In the title compound C₁₄ H₁₀ Br F₃ O₄, the coumarin ring system is plannar with the 2-bromo-2-methyl propanoate moiety almost perpendicular. The C—F bond lengths of 1.333 (2) Å,1.324 (3)Å and 1.331 (3)Å are normal in this structure. One F atom (F1) lie in plane with the coumarin ring system and the other two F atoms are above and below the plane. The torsion angle of C6—C7—O3—C11 and C8—C7—O3—C11 are -114.21 (3)° and 71.42 (2)° respectively. The crystal is stabilized by intermolecular C—H···O hydrogen bond.

Experimental

7-Hydroxy-4-trifluoromethylcoumarin 5 g (0.02 mole), triethylamine 4.83 g (0.04 mole) and THF (400 ml) were placed in a 3-neck round bottomed flask. Bromoisobutyrl bromide 10.9 g (0.04 mole) was added slowly, using a syringe, with stirring, upon which an white precipitate of triethylammonium bromide was formed. The mixture was left to react for 6 hours, with stirring. Subsequently, triethylammonium bromide, the precipitate was removed by filtration and the THF was removed by rotary evaporation. The resulting crude product was dissolved in ethyl acetate, washed with bicarbonate solution and then with water thrice followed by brine solution and dried over anhydrous sodium sulphate. The resulting solvent was removed by rotary evaporation. The product was purified by column chromatography technique using 15% ethyl acetate in hexane as the eluent to obtain pure initiator as a bright white solid. Recrystallization of the compound from chloroform gave colourless blocks of (I).