6,8-Dibromo-5-hydr­oxy-4-oxo-2-phenyl-4H-chromen-7-yl acetate

Angannan Nallasivam; Munirathinam Nethaji; Nagarajan Vembu; Venkatraman Ragunathan; Nagarajan Sulochana

doi:10.1107/S1600536809005431

. 2009 Feb 21;65(Pt 3):o568. doi: 10.1107/S1600536809005431

6,8-Dibromo-5-hydroxy-4-oxo-2-phenyl-4H-chromen-7-yl acetate

Angannan Nallasivam ^a, Munirathinam Nethaji ^b, Nagarajan Vembu ^c,^*, Venkatraman Ragunathan ^d, Nagarajan Sulochana ^a

PMCID: PMC2968645 PMID: 21582223

Abstract

In the title compound, C₁₇H₁₀Br₂O₅, the chromene ring is almost planar with minimal puckering [total puckering amplitude = 0.067 (4) Å]. The dihedral angle between chromeme ring system and phenyl ring is 3.7 (2)°. The crystal structure is stabilized by intermolecular C—H⋯O interactions and an intramolecular O—H⋯O hydrogen bond also occurs.

Related literature

For the biological and pharmacological properties of benzopyrans and their derivatives, see: Brooks (1998 ▶); Hatakeyama et al. (1988 ▶)); Hyana & Saimoto (1987 ▶); Tang et al. (2007 ▶). For the importance of 4H-chromenes, see: Liu et al. (2007 ▶); Wang, Fang et al. (2003 ▶); Wang, Zhang et al. (2003 ▶). For hydrogen bonding, see: Bernstein et al. (1995 ▶); Desiraju (1989 ▶); Desiraju & Steiner (1999 ▶); Etter (1990 ▶).

Experimental

Crystal data

C₁₇H₁₀Br₂O₅
M _r = 454.07
Monoclinic,
a = 14.072 (3) Å
b = 5.5586 (13) Å
c = 21.333 (5) Å
β = 104.501 (4)°
V = 1615.6 (7) Å³
Z = 4
Mo Kα radiation
μ = 5.04 mm⁻¹
T = 293 K
0.55 × 0.23 × 0.12 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1998 ▶) T _min = 0.157, T _max = 0.547
13326 measured reflections
3773 independent reflections
2245 reflections with I > 2σ(I)
R _int = 0.046

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.105
S = 0.99
3773 reflections
221 parameters
H-atom parameters constrained
Δρ_max = 0.57 e Å⁻³
Δρ_min = −0.37 e Å⁻³

Data collection: SMART (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809005431/er2060sup1.cif

e-65-0o568-sup1.cif^{(19.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809005431/er2060Isup2.hkl

e-65-0o568-Isup2.hkl^{(185KB, 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
O12—H12⋯O11	0.82	1.86	2.584 (4)	147
C3—H3⋯O11ⁱ	0.93	2.57	3.497 (4)	171
C24—H24⋯O11ⁱ	0.93	2.48	3.387 (5)	166
C17—H17A⋯O16ⁱⁱ	0.96	2.58	3.309 (6)	133

Open in a new tab

Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

AN thanks Dr S. Kannan and Dr B. S. Krishnamurthy, School of Chemistry, Bharathidasan University, Tiruchirappalli, and Organica Aromatics Pvt Ltd Bangalore, India, for providing laboratory facilities.

supplementary crystallographic information

Comment

Chromenes (benzopyrans) and their derivatives have numerous biological and pharmacological properties (Tang et al., 2007) such as antisterility (Brooks, 1998) and anticancer activity (Hyana & Saimoto, 1987). In addition, polyfunctionalized chromene units are present in numerous natural products (Hatakeyama et al., 1988). 4H-chromenes are important synthons for some natural products (Liu et al., 2007). As a part of our structural investigations on 4H-chromene derivatives and compounds containing the benzopyran fragment, the single-crystal X-ray diffraction study on the title compound was carried out.

The chromene ring is almost planar similarly as those found in the related chromene derivatives (Wang, Fang et al., 2003; Wang, Zhang et al., 2003). The total puckering amplitude of the chromene ring is 0.067 (4) Å in the title structure. The interplanar angle between the chromene ring and the 2-phenyl ring is 3.7 (2)° thereby indicating the almost coplanar arrangement (Fig. 1). The OCOCH₃ substituent at C7 is non-coplanar with the chromene ring as discerned from the interplanar angle of 87.4 (1)°.

The crystal structure is stabilized by the interplay of C–H···O and O–H···O interactions (Fig. 2 & Table 1). The H-bond distances agree with those reported in literature (Desiraju & Steiner, 1999; Desiraju, 1989). The C20–H20···O1 interaction generates a motif of graph set (Bernstein et al., 1995; Etter, 1990) S(5). An S(6) motif is formed by O12–H12···O11 interaction. This interaction is also responsible for the formation of a cooperative H-bonded network (Fig. 3). The C3–H3···O11ⁱ and C24–H24···O11ⁱ interactions constitute a pair of bifurcated acceptor bonds generating a ring of graph set R¹₂(7). There are no significant C—H···π and π···π interactions.

Experimental

In to the RBF, a suspension of chrysin (1 g, 3.93 mmol) and potassium carbonate (1.64 g, 11.81 mmol) in dimethyl formamide (10 ml) were added. The reaction mixture was heated to 383 K for 2–3 hrs. The reaction mixture was cooled to 313 K and acetyl chloride (1.23 g, 15.74 mmol) was slowly added with the help of dropping funnel. The reaction mixture was maintained for 8–9 hr at 313 K and monitored by HPLC. After completion of the reaction, the contents were quenched with water and stirred for 30–45 min at 303 K. The crude solid obtained was filtered and washed with plenty of water followed by methanol and dried under vacuum at 343 K. The acetylated compound was then taken in RBF and dissolved in dichloromethane (10 ml) and cooled to 273 K. Bromine (0.6 ml, 11.81 mmol) was added dropwise over a period of 15–20 min. The reaction mixture was maintained at 273 K for 5–6 hr. After completion of the reaction, the reaction mixture was quenched in ice water and extracted with dichloromethane (10 ml) and purified by column chromatography using ethyl acetate: n-hexane (20:80). The crude brominated product was then dissolved in dichloromethane (10 ml) and equal amount of n-Hexane (10 ml). The clear solution was kept for a week without stirring. Diffraction quality needle shaped crystals of average size 0.23 mm were obtained which were filtered and washed with n-hexane and dried under vacuum at 343 K. Yield: 80%