8-(2-Bromo-3-methoxy-3-methylbutyl)-7-methoxycoumarin

Anand Solomon, K.; Rajan, S.S.; Gopalakrishnan, G.; Kashinath, V.; Santhana Krishnan, V.P.

doi:10.1107/S0108270102020838

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8-(2-Bromo-3-methoxy-3-methylbutyl)-7-methoxycoumarin

K. Anand Solomon, S. S. Rajan, G. Gopalakrishnan, V. Kashinath and V. P. Santhana Krishnan

The title compound, C₁₆H₁₉BrO₄, is a derivative of osthol, isolated from the seeds of Imperatoria Osthruthium. The structure was solved in space group P $\overline 1$ , with two molecules in the asymmetric unit, and was refined to a final R factor of 0.064. The two molecules in the asymmetric unit differ in the orientation of their brominated substituent group. The benzopyran ring displays aromatic character. The packing of the molecules in the lattice is mainly due to C—H

O hydrogen bonds.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102020838/na1573sup1.cif Contains datablocks I, global
	Structure factor file (CIF format) https://doi.org/10.1107/S0108270102020838/na1573Isup2.hkl Contains datablock I

CCDC reference: 173576

Comment top

The title compound, (I), a derivative of osthol, is an antiinflammatory and antifungal drug (Akelah et al., 1981), and is the active principle of the seeds of Imperatoria Osthruthium used in the traditional Chinese system of medicine (Liu et al., 1998). The aim of the present work was to modify the isoprenyl group in osthol by a microwave-assisted reaction employing polymer-supported reagents and to study the change in activity resulting therefrom (Geetha Gopalakrishnan et al., 2000). \sch

The compound crystallizes in space group P1, with two molecules, A and B, in the asymmetric unit. The molecule has a chiral centre at C2' and the two molecules, A and B, differ in the orientation of the brominated substituent group; the configuration of molecule A is S, while that of B is R. Fig. 1 shows a diagram of (I) with the numbering scheme adopted for this molecule. Which?

In the benzopyran ring of (I), the average O1—C2 and C2—C3 distances in the two molecules are 1.381 (7) and 1.447 (9) Å, respectively, indicating that the electrons are delocalized in the ring with the carbonyl group acting as the electron-withdrawing group. This is corroborated by the fact that the benzopyran ring is planar.

Most of the bond lengths are similar in both molecules of (I). The maximum deviation is observed in the C7'-O3 bond [1.420 (5) Å in molecule A and 1.440 (5) Å in molecule B]. Atoms C1', C2', C3' and C5' are in a plane and are oriented at an angle of 174.1 (3)° (molecule A) and 173.2 (3)° (molecule B) with respect to the benzopyran ring.

In the packing of (I), molecules A and B run as layers along the b axis. The two independent molecules, as well as their symmetry-related molecules, are connected by C—H···O hydrogen bonds (Table 2).

Experimental top

The title derivative was prepared by bromomethoxylation of the double bond in the isoprenyl unit of osthol under microwave conditions employing a new polymer-supported bromine chloride resin. Unlike the normal cohalogenating reagents such as Br₂/MeOH, or N-bromosuccinamide in MeOH, which result in multiple products or pose difficulty in isolation (Batluenga & Martinez Gallo, 1985), the bromine chloride resin with osthol was a chemoselective and regioselective reaction, which proceeded quantitatively within 30 s, yielding the desired bromomethoxy compound, (I). To a solution of osthol (0.024 g, 1 mmol) in MeOH (10 ml), the polymer-supported bromine chloride resin [2 g, prepared by passing bromine over commercially available chloride resin (IRA-400)] was added and the mixture was irradiated in a modified domestic microwave oven fitted with a refluxing unit. On completion of the reaction, which was monitored by thin-layer chromatography, the resin was filtered and repeatedly washed with methanol, and the filtrate, after concentration, was purified by column chromatography (silica gel, 60–120 mesh, eluent EtOAc-hexane). The title compound was then crystallized in ethyl acetate by slow evaporation.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: SHELXL97 and PARST97 (Nardelli, 1995).

Figures top

Fig. 1. A view of the molecular structure of (I) with the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.

8-(2-Bromo-3-methoxy-3-methylbutyl)-7-methoxycoumarin top

Crystal data top

C₁₆H₁₉BrO₄	Z = 4
M_r = 355.21	F(000) = 728
Triclinic, P1	D_x = 1.508 Mg m⁻³
a = 10.280 (2) Å	Cu Kα radiation, λ = 1.54180 Å
b = 10.497 (4) Å	Cell parameters from 25 reflections
c = 16.175 (4) Å	θ = 15–30°
α = 75.91 (2)°	µ = 3.70 mm⁻¹
β = 80.81 (2)°	T = 293 K
γ = 68.00 (3)°	Block, colourless
V = 1565.1 (8) Å³	0.25 × 0.12 × 0.10 mm

Data collection top

Enraf-Nonius CAD-4 EXPRESS diffractometer	4992 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.070
Graphite monochromator	θ_max = 72.7°, θ_min = 2.8°
non–profiled ω/2θ scans	h = −11→12
Absorption correction: ψ scan (XRAYACS; Chandrasekaran, 1998)	k = −12→12
T_min = 0.458, T_max = 0.709	l = −19→19
6666 measured reflections	3 standard reflections every 120 min
6133 independent reflections	intensity decay: 5%

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.060	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.173	H-atom parameters constrained
S = 1.31	w = 1/[σ²(F_o²) + (0.1P)²] where P = (F_o² + 2F_c²)/3
6133 reflections	(Δ/σ)_max = 0.003
379 parameters	Δρ_max = 1.00 e Å⁻³
0 restraints	Δρ_min = −1.41 e Å⁻³

Crystal data top

C₁₆H₁₉BrO₄	γ = 68.00 (3)°
M_r = 355.21	V = 1565.1 (8) Å³
Triclinic, P1	Z = 4
a = 10.280 (2) Å	Cu Kα radiation
b = 10.497 (4) Å	µ = 3.70 mm⁻¹
c = 16.175 (4) Å	T = 293 K
α = 75.91 (2)°	0.25 × 0.12 × 0.10 mm
β = 80.81 (2)°

Data collection top

Enraf-Nonius CAD-4 EXPRESS diffractometer	4992 reflections with I > 2σ(I)
Absorption correction: ψ scan (XRAYACS; Chandrasekaran, 1998)	R_int = 0.070
T_min = 0.458, T_max = 0.709	3 standard reflections every 120 min
6666 measured reflections	intensity decay: 5%
6133 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.060	0 restraints
wR(F²) = 0.173	H-atom parameters constrained
S = 1.31	Δρ_max = 1.00 e Å⁻³
6133 reflections	Δρ_min = −1.41 e Å⁻³
379 parameters

Special details top

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.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C2A	0.2753 (5)	0.6502 (5)	−0.4263 (3)	0.0688 (11)
C3A	0.3471 (5)	0.6998 (5)	−0.5058 (4)	0.0767 (13)
H2A	0.4449	0.6686	−0.5113	0.092*
C4A	0.2748 (5)	0.7895 (6)	−0.5714 (3)	0.0747 (12)
H3A	0.3232	0.8196	−0.6213	0.090*
C5A	0.0436 (5)	0.9308 (5)	−0.6322 (3)	0.0654 (10)
H4A	0.0873	0.9639	−0.6833	0.079*
C6A	−0.0982 (5)	0.9715 (5)	−0.6229 (3)	0.0657 (10)
H5A	−0.1509	1.0323	−0.6676	0.079*
C7A	−0.1666 (4)	0.9232 (4)	−0.5470 (3)	0.0579 (9)
C8A	−0.0893 (4)	0.8294 (4)	−0.4782 (2)	0.0509 (8)
C9A	0.0558 (4)	0.7909 (4)	−0.4905 (2)	0.0523 (8)
C10A	0.1263 (4)	0.8387 (4)	−0.5655 (3)	0.0592 (9)
C1'A	−0.1586 (4)	0.7713 (4)	−0.3963 (2)	0.0525 (8)
H10A	−0.2586	0.8256	−0.3943	0.063*
H10B	−0.1208	0.7831	−0.3486	0.063*
C2'A	−0.1388 (4)	0.6160 (4)	−0.3853 (2)	0.0506 (8)
H11A	−0.0374	0.5635	−0.3888	0.061*
C3'A	−0.2024 (4)	0.5494 (4)	−0.2998 (2)	0.0532 (8)
C4'A	−0.3611 (5)	0.6191 (5)	−0.2851 (3)	0.0718 (12)
H13A	−0.3843	0.7180	−0.2899	0.108*
H13B	−0.3921	0.5795	−0.2290	0.108*
H13C	−0.4069	0.6039	−0.3272	0.108*
C5'A	−0.1629 (6)	0.3920 (5)	−0.2925 (3)	0.0749 (12)
H14A	−0.0627	0.3496	−0.3021	0.112*
H14B	−0.2082	0.3759	−0.3345	0.112*
H14C	−0.1929	0.3513	−0.2364	0.112*
C6'A	−0.0081 (5)	0.5118 (6)	−0.2185 (3)	0.0812 (14)
H15A	0.0126	0.5402	−0.1715	0.122*
H15B	0.0470	0.5372	−0.2691	0.122*
H15C	0.0141	0.4121	−0.2057	0.122*
C7'A	−0.3937 (6)	1.0623 (5)	−0.5976 (3)	0.0811 (14)
H16A	−0.4912	1.0803	−0.5788	0.122*
H16B	−0.3728	1.0268	−0.6494	0.122*
H16C	−0.3745	1.1477	−0.6080	0.122*
O1A	0.1298 (3)	0.7020 (3)	−0.42179 (18)	0.0571 (6)
O2A	0.3289 (4)	0.5704 (4)	−0.3626 (3)	0.0889 (10)
O3A	−0.3089 (3)	0.9617 (3)	−0.5335 (2)	0.0705 (8)
O4A	−0.1503 (3)	0.5785 (3)	−0.23183 (17)	0.0615 (7)
Br1	−0.21609 (5)	0.59293 (5)	−0.48282 (3)	0.06760 (12)
C2B	0.3097 (4)	−0.0344 (5)	0.1486 (2)	0.0556 (9)
C3B	0.2989 (4)	0.0974 (5)	0.1657 (3)	0.0636 (10)
H2B	0.2893	0.1080	0.2220	0.076*
C4B	0.3025 (4)	0.2064 (5)	0.1013 (3)	0.0626 (10)
H3B	0.2956	0.2903	0.1145	0.075*
C5B	0.3245 (4)	0.3019 (4)	−0.0562 (3)	0.0594 (9)
H4B	0.3212	0.3870	−0.0467	0.071*
C6B	0.3367 (4)	0.2843 (4)	−0.1376 (3)	0.0593 (9)
H5B	0.3423	0.3562	−0.1832	0.071*
C7B	0.3410 (4)	0.1569 (4)	−0.1527 (2)	0.0517 (8)
C8B	0.3327 (3)	0.0468 (3)	−0.0844 (2)	0.0450 (7)
C9B	0.3230 (3)	0.0689 (4)	−0.0030 (2)	0.0456 (7)
C10B	0.3166 (4)	0.1957 (4)	0.0143 (3)	0.0511 (8)
C1'B	0.3362 (4)	−0.0915 (4)	−0.0991 (2)	0.0464 (7)
H10C	0.4106	−0.1669	−0.0679	0.056*
H10D	0.3594	−0.0935	−0.1594	0.056*
C2'B	0.1984 (3)	−0.1190 (3)	−0.0718 (2)	0.0453 (7)
H11B	0.1744	−0.1123	−0.0115	0.054*
C3'B	0.2050 (4)	−0.2648 (4)	−0.0797 (2)	0.0481 (7)
C4'B	0.2374 (5)	−0.2880 (4)	−0.1714 (2)	0.0614 (10)
H13D	0.3230	−0.2718	−0.1949	0.092*
H13E	0.1615	−0.2241	−0.2052	0.092*
H13F	0.2480	−0.3827	−0.1719	0.092*
C5'B	0.0690 (4)	−0.2902 (5)	−0.0412 (3)	0.0653 (10)
H14D	0.0503	−0.2763	0.0166	0.098*
H14E	0.0787	−0.3845	−0.0418	0.098*
H14F	−0.0076	−0.2256	−0.0742	0.098*
C6'B	0.3216 (5)	−0.3863 (5)	0.0529 (3)	0.0717 (12)
H15D	0.4077	−0.4569	0.0729	0.107*
H15E	0.2437	−0.4149	0.0793	0.107*
H15F	0.3109	−0.2993	0.0675	0.107*
C7'B	0.3620 (6)	0.2408 (5)	−0.3044 (3)	0.0818 (14)
H16D	0.3728	0.2079	−0.3564	0.123*
H16E	0.4409	0.2670	−0.3014	0.123*
H16F	0.2769	0.3207	−0.3034	0.123*
O1B	0.3188 (3)	−0.0418 (3)	0.06375 (15)	0.0500 (5)
O2B	0.3103 (3)	−0.1396 (4)	0.20143 (18)	0.0711 (8)
O3B	0.3552 (3)	0.1309 (3)	−0.23227 (17)	0.0636 (7)
O4B	0.3251 (3)	−0.3681 (3)	−0.03703 (17)	0.0556 (6)
Br2	0.04615 (4)	0.03110 (4)	−0.13849 (3)	0.06098 (12)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C2A	0.060 (2)	0.065 (2)	0.086 (3)	−0.021 (2)	−0.016 (2)	−0.018 (2)
C3A	0.054 (2)	0.085 (3)	0.097 (4)	−0.031 (2)	0.004 (2)	−0.027 (3)
C4A	0.070 (3)	0.086 (3)	0.077 (3)	−0.037 (2)	0.010 (2)	−0.026 (3)
C5A	0.084 (3)	0.065 (2)	0.050 (2)	−0.034 (2)	0.002 (2)	−0.0097 (18)
C6A	0.077 (3)	0.061 (2)	0.055 (2)	−0.021 (2)	−0.012 (2)	−0.0052 (18)
C7A	0.063 (2)	0.051 (2)	0.055 (2)	−0.0147 (17)	−0.0043 (17)	−0.0106 (16)
C8A	0.057 (2)	0.0465 (18)	0.0485 (18)	−0.0165 (15)	−0.0022 (15)	−0.0128 (15)
C9A	0.061 (2)	0.0461 (18)	0.0526 (19)	−0.0192 (16)	−0.0022 (16)	−0.0150 (15)
C10A	0.062 (2)	0.060 (2)	0.060 (2)	−0.0259 (18)	0.0046 (18)	−0.0184 (18)
C1'A	0.054 (2)	0.0499 (19)	0.0494 (19)	−0.0122 (15)	−0.0025 (15)	−0.0124 (15)
C2'A	0.054 (2)	0.0516 (19)	0.0457 (18)	−0.0157 (15)	−0.0065 (15)	−0.0120 (15)
C3'A	0.061 (2)	0.054 (2)	0.0475 (19)	−0.0225 (17)	−0.0085 (16)	−0.0089 (15)
C4'A	0.058 (2)	0.091 (3)	0.058 (2)	−0.022 (2)	−0.0055 (19)	−0.006 (2)
C5'A	0.105 (4)	0.056 (2)	0.068 (3)	−0.034 (2)	−0.011 (2)	−0.006 (2)
C6'A	0.066 (3)	0.115 (4)	0.065 (3)	−0.032 (3)	−0.019 (2)	−0.013 (3)
C7'A	0.074 (3)	0.076 (3)	0.083 (3)	−0.016 (2)	−0.031 (3)	0.000 (3)
O1A	0.0535 (14)	0.0580 (15)	0.0608 (15)	−0.0189 (12)	−0.0085 (12)	−0.0118 (12)
O2A	0.070 (2)	0.089 (2)	0.103 (3)	−0.0258 (18)	−0.0284 (19)	0.001 (2)
O3A	0.0598 (17)	0.0681 (18)	0.0680 (18)	−0.0092 (14)	−0.0106 (14)	−0.0028 (14)
O4A	0.0663 (17)	0.0702 (17)	0.0485 (14)	−0.0219 (14)	−0.0089 (12)	−0.0131 (12)
Br1	0.0844 (3)	0.0761 (3)	0.0522 (2)	−0.0341 (2)	−0.0137 (2)	−0.0158 (2)
C2B	0.0421 (18)	0.075 (3)	0.050 (2)	−0.0212 (17)	−0.0014 (15)	−0.0149 (18)
C3B	0.056 (2)	0.085 (3)	0.056 (2)	−0.023 (2)	0.0014 (18)	−0.032 (2)
C4B	0.052 (2)	0.068 (2)	0.076 (3)	−0.0188 (18)	−0.0003 (19)	−0.036 (2)
C5B	0.058 (2)	0.0441 (19)	0.078 (3)	−0.0168 (16)	−0.0053 (19)	−0.0189 (18)
C6B	0.057 (2)	0.0478 (19)	0.070 (2)	−0.0180 (16)	−0.0064 (18)	−0.0061 (17)
C7B	0.0464 (18)	0.0520 (19)	0.055 (2)	−0.0161 (15)	−0.0035 (15)	−0.0100 (16)
C8B	0.0415 (16)	0.0447 (17)	0.0496 (18)	−0.0127 (13)	−0.0065 (13)	−0.0125 (14)
C9B	0.0368 (15)	0.0485 (18)	0.0523 (19)	−0.0144 (13)	−0.0024 (13)	−0.0129 (14)
C10B	0.0401 (17)	0.0523 (19)	0.064 (2)	−0.0134 (14)	−0.0045 (15)	−0.0220 (16)
C1'B	0.0438 (17)	0.0450 (17)	0.0506 (18)	−0.0139 (13)	−0.0041 (14)	−0.0120 (14)
C2'B	0.0445 (17)	0.0461 (17)	0.0447 (17)	−0.0136 (14)	−0.0055 (13)	−0.0101 (14)
C3'B	0.0470 (18)	0.0471 (17)	0.0510 (19)	−0.0146 (14)	−0.0080 (14)	−0.0117 (14)
C4'B	0.079 (3)	0.058 (2)	0.055 (2)	−0.026 (2)	−0.0041 (19)	−0.0215 (17)
C5'B	0.060 (2)	0.066 (2)	0.079 (3)	−0.032 (2)	−0.005 (2)	−0.015 (2)
C6'B	0.089 (3)	0.060 (2)	0.062 (3)	−0.022 (2)	−0.022 (2)	−0.0012 (19)
C7'B	0.106 (4)	0.074 (3)	0.053 (2)	−0.030 (3)	−0.003 (2)	0.004 (2)
O1B	0.0534 (14)	0.0533 (13)	0.0462 (13)	−0.0212 (11)	−0.0040 (10)	−0.0110 (10)
O2B	0.079 (2)	0.089 (2)	0.0495 (15)	−0.0385 (17)	−0.0022 (14)	−0.0096 (14)
O3B	0.0820 (19)	0.0616 (16)	0.0474 (14)	−0.0285 (14)	−0.0056 (13)	−0.0054 (12)
O4B	0.0573 (15)	0.0468 (13)	0.0605 (15)	−0.0147 (11)	−0.0108 (12)	−0.0080 (11)
Br2	0.0505 (2)	0.0572 (2)	0.0689 (3)	−0.00566 (17)	−0.01745 (18)	−0.01409 (19)

Geometric parameters (Å, º) top

C2A—O2A	1.217 (6)	C2B—O2B	1.220 (5)
C2A—O1A	1.383 (5)	C2B—O1B	1.379 (4)
C2A—C3A	1.459 (7)	C2B—C3B	1.436 (6)
C3A—C4A	1.343 (7)	C3B—C4B	1.354 (6)
C3A—H2A	0.9300	C3B—H2B	0.9300
C4A—C10A	1.412 (6)	C4B—C10B	1.420 (6)
C4A—H3A	0.9300	C4B—H3B	0.9300
C5A—C6A	1.351 (6)	C5B—C6B	1.354 (6)
C5A—C10A	1.412 (6)	C5B—C10B	1.403 (6)
C4A—H3A	0.9300	C5B—H4B	0.9300
C6A—C7A	1.395 (6)	C6B—C7B	1.401 (5)
C6A—H5A	0.9300	C6B—H5B	0.9300
C7A—O3A	1.360 (5)	C7B—O3B	1.353 (4)
C7A—C8A	1.414 (5)	C7B—C8B	1.410 (5)
C8A—C9A	1.386 (5)	C8B—C9B	1.373 (5)
C8A—C1'A	1.505 (5)	C8B—C1'B	1.515 (4)
C9A—O1A	1.384 (5)	C9B—O1B	1.389 (4)
C9A—C10A	1.394 (5)	C9B—C10B	1.402 (5)
C1'A—C2'A	1.535 (5)	C1'B—C2'B	1.526 (5)
C1'A—H10A	0.9700	C1'B—H10C	0.9700
C1'A—H10B	0.9700	C1'B—H10D	0.9700
C2'A—C3'A	1.552 (5)	C2'B—C3'B	1.543 (5)
C2'A—Br1	1.977 (4)	C2'B—Br2	1.990 (3)
C2'A—H11A	0.9800	C2'B—H11B	0.9800
C3'A—O4A	1.437 (4)	C3'B—O4B	1.443 (4)
C3'A—C4'A	1.524 (6)	C3'B—C4'B	1.525 (5)
C3'A—C5'A	1.526 (5)	C3'B—C5'B	1.528 (5)
C4'A—H13A	0.9600	C4'B—H13D	0.9600
C4'A—H13B	0.9600	C4'B—H13E	0.9600
C4'A—H13C	0.9600	C4'B—H13F	0.9600
C5'A—H14A	0.9600	C5'B—H14D	0.9600
C5'A—H14B	0.9600	C5'B—H14E	0.9600
C5'A—H14C	0.9600	C5'B—H14F	0.9600
C6'A—O4A	1.390 (5)	C6'B—O4B	1.416 (5)
C6'A—H15A	0.9600	C6'B—H15D	0.9600
C6'A—H15B	0.9600	C6'B—H15E	0.9600
C6'A—H15C	0.9600	C6'B—H15F	0.9600
C7'A—O3A	1.420 (5)	C7'B—O3B	1.440 (5)
C7'A—H16A	0.9600	C7'B—H16D	0.9600
C7'A—H16B	0.9600	C7'B—H16E	0.9600
C7'A—H16C	0.9600	C7'B—H16F	0.9600

O2A—C2A—O1A	116.1 (5)	O2B—C2B—O1B	116.9 (4)
O2A—C2A—C3A	127.3 (5)	O2B—C2B—C3B	126.6 (4)
O1A—C2A—C3A	116.5 (4)	O1B—C2B—C3B	116.5 (4)
C4A—C3A—C2A	121.3 (4)	C4B—C3B—C2B	121.3 (4)
C4A—C3A—H2A	119.3	C4B—C3B—H2B	119.4
C2A—C3A—H2A	119.3	C2B—C3B—H2B	119.4
C3A—C4A—C10A	120.9 (4)	C3B—C4B—C10B	121.5 (4)
C3A—C4A—H3A	119.6	C3B—C4B—H3B	119.2
C10A—C4A—H3A	119.6	C10B—C4B—H3B	119.2
C6A—C5A—C10A	120.9 (4)	C6B—C5B—C10B	122.0 (3)
C6A—C5A—H4A	119.5	C6B—C5B—H4B	119.0
C10A—C5A—H4A	119.5	C10B—C5B—H4B	119.0
C5A—C6A—C7A	120.7 (4)	C5B—C6B—C7B	119.5 (4)
C5A—C6A—H5A	119.6	C5B—C6B—H5B	120.2
C7A—C6A—H5A	119.6	C7B—C6B—H5B	120.2
O3A—C7A—C6A	123.4 (4)	O3B—C7B—C6B	122.8 (3)
O3A—C7A—C8A	115.7 (3)	O3B—C7B—C8B	116.2 (3)
C6A—C7A—C8A	120.9 (4)	C6B—C7B—C8B	120.9 (4)
C9A—C8A—C7A	116.4 (3)	C9B—C8B—C7B	117.4 (3)
C9A—C8A—C1'A	121.0 (3)	C9B—C8B—C1'B	120.7 (3)
C7A—C8A—C1'A	122.6 (4)	C7B—C8B—C1'B	121.9 (3)
O1A—C9A—C8A	115.7 (3)	C8B—C9B—O1B	116.8 (3)
O1A—C9A—C10A	120.6 (4)	C8B—C9B—C10B	123.1 (3)
C8A—C9A—C10A	123.7 (4)	O1B—C9B—C10B	120.1 (3)
C9A—C10A—C5A	117.3 (4)	C9B—C10B—C5B	117.1 (3)
C9A—C10A—C4A	118.6 (4)	C9B—C10B—C4B	117.6 (4)
C5A—C10A—C4A	124.0 (4)	C5B—C10B—C4B	125.3 (4)
C8A—C1'A—C2'A	114.1 (3)	C8B—C1'B—C2'B	114.2 (3)
C8A—C1'A—H10A	108.7	C8B—C1'B—H10C	108.7
C2'A—C1'A—H10A	108.7	C2'B—C1'B—H10C	108.7
C8A—C1'A—H10B	108.7	C8B—C1'B—H10D	108.7
C2'A—C1'A—H10B	108.7	C2'B—C1'B—H10D	108.7
H10A—C1'A—H10B	107.6	H10C—C1'B—H10D	107.6
C1'A—C2'A—C3'A	116.0 (3)	C1'B—C2'B—C3'B	114.4 (3)
C1'A—C2'A—Br1	108.5 (2)	C1'B—C2'B—Br2	109.2 (2)
C3'A—C2'A—Br1	110.0 (3)	C3'B—C2'B—Br2	110.3 (2)
C1'A—C2'A—H11A	107.3	C1'B—C2'B—H11B	107.6
C3'A—C2'A—H11A	107.3	C3'B—C2'B—H11B	107.6
Br1—C2'A—H11A	107.3	Br2—C2'B—H11B	107.6
O4A—C3'A—C4'A	102.7 (3)	O4B—C3'B—C4'B	103.2 (3)
O4A—C3'A—C5'A	111.3 (3)	O4B—C3'B—C5'B	111.4 (3)
C4'A—C3'A—C5'A	110.5 (4)	C4'B—C3'B—C5'B	110.3 (3)
O4A—C3'A—C2'A	107.3 (3)	O4B—C3'B—C2'B	107.7 (3)
C4'A—C3'A—C2'A	113.7 (3)	C4'B—C3'B—C2'B	113.2 (3)
C5'A—C3'A—C2'A	111.1 (3)	C5'B—C3'B—C2'B	110.9 (3)
C3'A—C4'A—H13A	109.5	C3'B—C4'B—H13D	109.5
C3'A—C4'A—H13B	109.5	C3'B—C4'B—H13E	109.5
H13A—C4'A—H13B	109.5	H13D—C4'B—H13E	109.5
C3'A—C4'A—H13C	109.5	C3'B—C4'B—H13F	109.5
H13A—C4'A—H13C	109.5	H13D—C4'B—H13F	109.5
H13B—C4'A—H13C	109.5	H13E—C4'B—H13F	109.5
C3'A—C5'A—H14A	109.5	C3'B—C5'B—H14D	109.5
C3'A—C5'A—H14B	109.5	C3'B—C5'B—H14E	109.5
H14A—C5'A—H14B	109.5	H14D—C5'B—H14E	109.5
C3'A—C5'A—H14C	109.5	C3'B—C5'B—H14F	109.5
H14A—C5'A—H14C	109.5	H14D—C5'B—H14F	109.5
H14B—C5'A—H14C	109.5	H14E—C5'B—H14F	109.5
O4A—C6'A—H15A	109.5	O4B—C6'B—H15D	109.5
O4A—C6'A—H15B	109.5	O4B—C6'B—H15E	109.5
H15A—C6'A—H15B	109.5	H15D—C6'B—H15E	109.5
O4A—C6'A—H15C	109.5	O4B—C6'B—H15F	109.5
H15A—C6'A—H15C	109.5	H15D—C6'B—H15F	109.5
H15B—C6'A—H15C	109.5	H15E—C6'B—H15F	109.5
O3A—C7'A—H16A	109.5	O3B—C7'B—H16D	109.5
O3A—C7'A—H16B	109.5	O3B—C7'B—H16E	109.5
H16A—C7'A—H16B	109.5	H16D—C7'B—H16E	109.5
O3A—C7'A—H16C	109.5	O3B—C7'B—H16F	109.5
H16A—C7'A—H16C	109.5	H16D—C7'B—H16F	109.5
H16B—C7'A—H16C	109.5	H16E—C7'B—H16F	109.5
C2A—O1A—C9A	121.9 (3)	C2B—O1B—C9B	122.9 (3)
C7A—O3A—C7'A	118.9 (4)	C7B—O3B—C7'B	118.4 (3)
C6'A—O4A—C3'A	118.0 (3)	C6'B—O4B—C3'B	118.0 (3)

O2A—C2A—C3A—C4A	−179.4 (5)	O2B—C2B—C3B—C4B	178.5 (4)
O1A—C2A—C3A—C4A	−0.9 (7)	O1B—C2B—C3B—C4B	−2.2 (6)
C2A—C3A—C4A—C10A	−0.2 (8)	C2B—C3B—C4B—C10B	0.2 (6)
C10A—C5A—C6A—C7A	−0.1 (7)	C10B—C5B—C6B—C7B	0.4 (6)
C5A—C6A—C7A—O3A	179.2 (4)	C5B—C6B—C7B—O3B	−179.0 (4)
C5A—C6A—C7A—C8A	−0.7 (7)	C5B—C6B—C7B—C8B	0.0 (6)
O3A—C7A—C8A—C9A	−179.0 (3)	O3B—C7B—C8B—C9B	177.9 (3)
C6A—C7A—C8A—C9A	0.9 (6)	C6B—C7B—C8B—C9B	−1.1 (5)
O3A—C7A—C8A—C1'A	2.0 (6)	O3B—C7B—C8B—C1'B	−1.4 (5)
C6A—C7A—C8A—C1'A	−178.1 (4)	C6B—C7B—C8B—C1'B	179.6 (3)
C7A—C8A—C9A—O1A	178.4 (3)	C7B—C8B—C9B—O1B	−178.3 (3)
C1'A—C8A—C9A—O1A	−2.7 (5)	C1'B—C8B—C9B—O1B	1.0 (5)
C7A—C8A—C9A—C10A	−0.4 (6)	C7B—C8B—C9B—C10B	2.0 (5)
C1'A—C8A—C9A—C10A	178.6 (4)	C1'B—C8B—C9B—C10B	−178.7 (3)
O1A—C9A—C10A—C5A	−179.0 (3)	C8B—C9B—C10B—C5B	−1.7 (5)
C8A—C9A—C10A—C5A	−0.3 (6)	O1B—C9B—C10B—C5B	178.6 (3)
O1A—C9A—C10A—C4A	2.9 (6)	C8B—C9B—C10B—C4B	178.2 (3)
C8A—C9A—C10A—C4A	−178.4 (4)	O1B—C9B—C10B—C4B	−1.5 (5)
C6A—C5A—C10A—C9A	0.6 (6)	C6B—C5B—C10B—C9B	0.4 (6)
C6A—C5A—C10A—C4A	178.6 (4)	C6B—C5B—C10B—C4B	−179.4 (4)
C3A—C4A—C10A—C9A	−0.8 (7)	C3B—C4B—C10B—C9B	1.7 (6)
C3A—C4A—C10A—C5A	−178.7 (4)	C3B—C4B—C10B—C5B	−178.5 (4)
C9A—C8A—C1'A—C2'A	−71.4 (5)	C9B—C8B—C1'B—C2'B	68.2 (4)
C7A—C8A—C1'A—C2'A	107.5 (4)	C7B—C8B—C1'B—C2'B	−112.6 (4)
C8A—C1'A—C2'A—C3'A	177.2 (3)	C8B—C1'B—C2'B—C3'B	−175.2 (3)
C8A—C1'A—C2'A—Br1	−58.4 (4)	C8B—C1'B—C2'B—Br2	60.6 (3)
C1'A—C2'A—C3'A—O4A	−52.3 (4)	C1'B—C2'B—C3'B—O4B	51.1 (4)
Br1—C2'A—C3'A—O4A	−175.9 (2)	Br2—C2'B—C3'B—O4B	174.6 (2)
C1'A—C2'A—C3'A—C4'A	60.5 (5)	C1'B—C2'B—C3'B—C4'B	−62.3 (4)
Br1—C2'A—C3'A—C4'A	−63.0 (4)	Br2—C2'B—C3'B—C4'B	61.2 (3)
C1'A—C2'A—C3'A—C5'A	−174.1 (3)	C1'B—C2'B—C3'B—C5'B	173.2 (3)
Br1—C2'A—C3'A—C5'A	62.3 (4)	Br2—C2'B—C3'B—C5'B	−63.3 (3)
O2A—C2A—O1A—C9A	−178.3 (4)	O2B—C2B—O1B—C9B	−178.2 (3)
C3A—C2A—O1A—C9A	3.0 (6)	C3B—C2B—O1B—C9B	2.4 (5)
C8A—C9A—O1A—C2A	177.1 (3)	C8B—C9B—O1B—C2B	179.7 (3)
C10A—C9A—O1A—C2A	−4.1 (5)	C10B—C9B—O1B—C2B	−0.5 (5)
C6A—C7A—O3A—C7'A	−3.8 (6)	C6B—C7B—O3B—C7'B	−1.9 (6)
C8A—C7A—O3A—C7'A	176.1 (4)	C8B—C7B—O3B—C7'B	179.1 (4)
C4'A—C3'A—O4A—C6'A	170.8 (4)	C4'B—C3'B—O4B—C6'B	−172.9 (3)
C5'A—C3'A—O4A—C6'A	52.6 (5)	C5'B—C3'B—O4B—C6'B	−54.6 (4)
C2'A—C3'A—O4A—C6'A	−69.0 (5)	C2'B—C3'B—O4B—C6'B	67.2 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2′B—H11B···O1B	0.98	2.46	3.078 (4)	120
C1′B—H10C···O4B	0.97	2.49	2.871 (4)	102
C1′B—H10D···O3B	0.97	2.35	2.809 (4)	108
C2′A—H11A···O1A	0.98	2.56	3.143 (5)	118
C1′A—H10B···O4A	0.97	2.57	2.916 (5)	101
C4B—H3B···O4Aⁱ	0.93	2.56	3.258 (4)	132

Symmetry code: (i) −x, −y+1, −z.

Experimental details

Crystal data
Chemical formula	C₁₆H₁₉BrO₄
M_r	355.21
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	10.280 (2), 10.497 (4), 16.175 (4)
α, β, γ (°)	75.91 (2), 80.81 (2), 68.00 (3)
V (Å³)	1565.1 (8)
Z	4
Radiation type	Cu Kα
µ (mm⁻¹)	3.70
Crystal size (mm)	0.25 × 0.12 × 0.10

Data collection
Diffractometer	Enraf-Nonius CAD-4 EXPRESS diffractometer
Absorption correction	ψ scan (XRAYACS; Chandrasekaran, 1998)
T_min, T_max	0.458, 0.709
No. of measured, independent and observed [I > 2σ(I)] reflections	6666, 6133, 4992
R_int	0.070
(sin θ/λ)_max (Å⁻¹)	0.619

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.060, 0.173, 1.31
No. of reflections	6133
No. of parameters	379
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.00, −1.41

Computer programs: CAD-4 EXPRESS (Enraf-Nonius, 1994), CAD-4 EXPRESS, XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEPIII (Burnett & Johnson, 1996), SHELXL97 and PARST97 (Nardelli, 1995).

Selected geometric parameters (Å, º) top

C2A—O2A	1.217 (6)	C2B—O2B	1.220 (5)
C2A—O1A	1.383 (5)	C2B—O1B	1.379 (4)
C7A—O3A	1.360 (5)	C7B—O3B	1.353 (4)
C2'A—Br1	1.977 (4)	C2'B—Br2	1.990 (3)
C6'A—O4A	1.390 (5)	C6'B—O4B	1.416 (5)
C7'A—O3A	1.420 (5)

O2A—C2A—O1A	116.1 (5)	O2B—C2B—O1B	116.9 (4)
C9A—C8A—C1'A	121.0 (3)	C9B—C8B—C7B	117.4 (3)
C1'A—C2'A—Br1	108.5 (2)	C1'B—C2'B—Br2	109.2 (2)
C3'A—C2'A—Br1	110.0 (3)	C3'B—C2'B—Br2	110.3 (2)
O4A—C3'A—C5'A	111.3 (3)	O4B—C3'B—C4'B	103.2 (3)
C7A—O3A—C7'A	118.9 (4)	C7B—O3B—C7'B	118.4 (3)
C6'A—O4A—C3'A	118.0 (3)	C6'B—O4B—C3'B	118.0 (3)

C7A—C8A—C1'A—C2'A	107.5 (4)	C7B—C8B—C1'B—C2'B	−112.6 (4)
C8A—C1'A—C2'A—C3'A	177.2 (3)	C8B—C1'B—C2'B—C3'B	−175.2 (3)
C8A—C1'A—C2'A—Br1	−58.4 (4)	C8B—C1'B—C2'B—Br2	60.6 (3)
C8A—C7A—O3A—C7'A	176.1 (4)	C8B—C7B—O3B—C7'B	179.1 (4)
C4'A—C3'A—O4A—C6'A	170.8 (4)	C4'B—C3'B—O4B—C6'B	−172.9 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2'B—H11B···O1B	0.98	2.46	3.078 (4)	120
C1'B—H10C···O4B	0.97	2.49	2.871 (4)	102
C1'B—H10D···O3B	0.97	2.35	2.809 (4)	108
C2'A—H11A···O1A	0.98	2.56	3.143 (5)	118
C1'A—H10B···O4A	0.97	2.57	2.916 (5)	101
C4B—H3B···O4Aⁱ	0.93	2.56	3.258 (4)	132

Symmetry code: (i) −x, −y+1, −z.

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