2-Bromo-1,6,6-trimethyl-6,7,8,9-tetra­hydro­phenanthro[1,2-b]furan-10,11-dione

Cui-Ping Fan; Wei-Ping Yin; Xin-Xiang Cao; Jing-Cai Yao

doi:10.1107/S1600536813011483

. 2013 May 4;69(Pt 6):o834. doi: 10.1107/S1600536813011483

2-Bromo-1,6,6-trimethyl-6,7,8,9-tetrahydrophenanthro[1,2-b]furan-10,11-dione

Cui-Ping Fan ^a,^b,^*, Wei-Ping Yin ^a, Xin-Xiang Cao ^b, Jing-Cai Yao ^b

PMCID: PMC3684922 PMID: 23795024

Abstract

In the title compound, C₁₉H₁₇BrO₃, the ring skeleton is located on a crystallographic mirror plane; two C atoms of the cyclohexene ring are disordered over the two locations to satisfy the preferred ring conformation. In the crystal, C—H⋯O hydrogen bonds link the molecules into chains along the a axis. π–π stacking interactions between benzoquinone rings, with a centroid–centroid distance of 3.7225 (4) Å, are also observed, which connect the chains into a two-dimensional networkparallel to the ab plane.

Related literature

The title compound is a derivative of Tanshinone IIA, the major active component isolated from the Chinese herbal medicine danshen, which is used in the treatment of coronary heart disease (Chang et al., 1991 ▶; Wang et al., 2005 ▶), myocardial infarction and angina pectoris (Xue et al., 1999 ▶) and has antitumour activity (Ryu et al., 1997 ▶). For the structure of 1,6,6-trimethyl-6,7,8,9-tetrahydrophenanthro[1,2-b]furan-10,11-dione, see: Liu & Gao (2007 ▶).

Experimental

Crystal data

C₁₉H₁₇BrO₃
M _r = 373.24
Monoclinic,
a = 9.6063 (12) Å
b = 7.0457 (9) Å
c = 11.9688 (15) Å
β = 96.723 (1)°
V = 804.52 (18) Å³
Z = 2
Mo Kα radiation
μ = 2.57 mm⁻¹
T = 296 K
0.48 × 0.15 × 0.12 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.372, T _max = 0.748
6178 measured reflections
1634 independent reflections
1177 reflections with I > 2σ(I)
R _int = 0.046

Refinement

R[F ² > 2σ(F ²)] = 0.033
wR(F ²) = 0.087
S = 1.02
1634 reflections
144 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.41 e Å⁻³

Data collection: SMART (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Click here for additional data file.^{(21.4KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813011483/kp2449sup1.cif

e-69-0o834-sup1.cif^{(21.4KB, cif)}

Click here for additional data file.^{(80.5KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813011483/kp2449Isup2.hkl

e-69-0o834-Isup2.hkl^{(80.5KB, 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
C6—H6⋯O2ⁱ	0.93	2.39	3.322 (4)	177

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Symmetry code: (i) Inline graphic .

Acknowledgments

We are grateful for financial support from the Natural Science Foundation of Henan Province of China (092102310075).

supplementary crystallographic information

Comment

The Chinese herbal medicine, danshen, comes from the dried root of Salvia miltiorrhiza Bunge and Salvia przewalskii Maxim(Labiatae). Tanshinone IIA is the major active component isolated from danshen, which has unique curative effect in treating coronary heart disease (Chang et al., 1991; Wang et al., 2005), antitumour (Ryu et al., 1997), myocardial infarction and angina pectoris (Xue et al., 1999). The title compound, C₁₉H₁₇BrO₃, is derivative obtained by modification of Tanshinone IIA and may be used for obtaining molecules with higher bioactivity and better solubility.

The crystal structure of (I) contains three six-membered rings forming a phenanthrene dione system with a five-membered methylfuran ring fused to the dione ring (Fig. 1). The bond distance of C7-C8 agree with the corresponding distance of 1.564 (3) Å reported for 1,6,6-trimethyl-6,7,8,9-tetrahydrophenanthro[1,2-b]furan-10,11- -dione (Liu et al., 2007), indicating the nonconjugation system of the C3, C4, C7-C10 ring. The bond distance of Br1-C12 is 1.852 (3) Å. The ring skeleton is located at the crystallographic mirror plane except the atoms C15 and C16 which are disordered over two locations. Thus, the terminal six-membered ring is in a twist form with torsion angles C1-C2-C14-C15 = 19.8 (2)°, C1-C2-C16-C17 = 13.5 (2)°, the deviations of C15, C16, C18, C18A from the least square plane are 0.4867Å, -0.3383Å, -1.2396Å and 1.2396Å, respectively. Intermolecular C—H···O hydrogen bonds of d(O2···C6) = 3.322 (4) Å link the title molecules into a one-dimensional chain along the a axis (Table 1). The pi-pi stacking interactions between benzoquinone rings with the centroid-centroid distance of 3.7225 (4) Å [symmetry operations involved: 1-x,-1/2+y,-z;1-x,1/2+y-z;1-x,-1-y,-z;1-x,2-y,-z] are observed in the crystal structure.

Experimental

Tanshinone IIA (0.3 mmol) was added to dry dichloromethane(15 mL)in a three neck flask. The mixture was stirred and was heated to reflux temperature. And then, N-bromosuccinimide(0.36mmol) and benzoyl peroxide(0.03mmol) were dropped into the flask. After reflux reaction for 9h and left stirring about 17h at room temperature, the solvent in flask was evaporated. The residue was purified by column chromatography on silica gel with ethyl acetate/petroleum ether to afford the title compound solid (109 mg, yield 97.08%). The crimson crystals of the title compound for structure determination were obtained from recrystallization of the product from ethyl acetate at room temperature.