Isopropyl ent-15α-bromo-16-oxo-beyeran-19-oate.

The title compound, C(23)H(35)BrO(3), synthesized by esterification and bromination of isosteviol, comprises a fused four-ring system. Two of the six-membered rings adopt a regular chair conformation, whereas the remaining six-membered ring is an unsymmetrical distorted chair. The stereochemistry at the two six-membered ring junctions is trans, while the five-membered ring adopts an envelope conformation.

Related literature

For the pharmacological activity of isosteviol, see: Liu et al. (2001 ▶); Mizushina et al. (2005 ▶); Wong et al. (2004 ▶); Xu et al. (2007 ▶). For ring conformations, see: Cremer & Pople (1975 ▶). For the synthesis of isosteviol derivates via esterification and bromination, see: Cai et al. (2009 ▶); Shi (2010 ▶); Wu et al. (2009 ▶).

Experimental

Crystal data

C23H35BrO3

M = 439.42

Orthorhombic,

a = 11.203 (3) Å

b = 11.800 (3) Å

c = 16.988 (5) Å

V = 2245.8 (11) Å3

Z = 4

Mo Kα radiation

μ = 1.85 mm−1

T = 298 K

0.50 × 0.45 × 0.41 mm

Data collection

Bruker SMART CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 1999 ▶) T min = 0.458, T max = 0.518

11796 measured reflections

3944 independent reflections

2383 reflections with I > 2σ(I)

R int = 0.093

Refinement

R[F 2 > 2σ(F 2)] = 0.047

wR(F 2) = 0.108

S = 0.96

3944 reflections

245 parameters

H-atom parameters constrained

Δρmax = 0.40 e Å−3

Δρmin = −0.26 e Å−3

Absolute structure: Flack (1983 ▶), 1687 Friedel pairs

Flack parameter: −0.024 (13)

Data collection: SMART (Bruker, 1999 ▶); cell refinement: SAINT (Bruker, 1999 ▶); 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 and PLATON (Spek, 2009 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810002138/fj2269sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810002138/fj2269Isup2.hkl

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

C23H35BrO3	Dx = 1.300 Mg m−3
Mr = 439.42	Melting point = 396–397 K
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 2087 reflections
a = 11.203 (3) Å	θ = 2.2–17.6°
b = 11.800 (3) Å	µ = 1.85 mm−1
c = 16.988 (5) Å	T = 298 K
V = 2245.8 (11) Å3	Block, colourless
Z = 4	0.50 × 0.45 × 0.41 mm
F(000) = 928

Bruker SMART CCD area-detector diffractometer	3944 independent reflections
Radiation source: fine-focus sealed tube	2383 reflections with I > 2σ(I)
graphite	Rint = 0.093
phi and ω scans	θmax = 25.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −13→12
Tmin = 0.458, Tmax = 0.518	k = −9→14
11796 measured reflections	l = −20→19

Refinement on F2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F2 > 2σ(F2)] = 0.047	w = 1/[σ2(Fo2) + (0.0375P)2] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.108	(Δ/σ)max < 0.001
S = 0.96	Δρmax = 0.40 e Å−3
3944 reflections	Δρmin = −0.26 e Å−3
245 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraints	Extinction coefficient: 0.0190 (12)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 1687 Friedel pairs
Secondary atom site location: difference Fourier map	Flack parameter: −0.024 (13)

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.

	x	y	z	Uiso*/Ueq
Br1	0.68536 (6)	0.37853 (5)	0.23962 (3)	0.0740 (3)
O1	0.8434 (3)	0.8337 (3)	0.2930 (2)	0.0733 (12)
O2	0.9186 (4)	0.9167 (3)	0.3975 (2)	0.0694 (12)
O3	0.7310 (4)	0.2287 (3)	0.3988 (3)	0.0794 (13)
C1	0.7080 (4)	0.8666 (4)	0.3967 (2)	0.0385 (12)
C2	0.7046 (5)	0.9117 (4)	0.4811 (3)	0.0498 (14)
H2A	0.7466	0.9836	0.4828	0.060*
H2B	0.6221	0.9260	0.4954	0.060*
C3	0.7588 (5)	0.8336 (4)	0.5414 (3)	0.0541 (15)
H3A	0.7474	0.8655	0.5935	0.065*
H3B	0.8439	0.8273	0.5320	0.065*
C4	0.7018 (5)	0.7149 (4)	0.5382 (2)	0.0459 (13)
H4A	0.7434	0.6656	0.5748	0.055*
H4B	0.6194	0.7203	0.5553	0.055*
C5	0.7051 (4)	0.6609 (3)	0.4559 (2)	0.0323 (11)
C6	0.6208 (4)	0.5550 (3)	0.4581 (3)	0.0320 (11)
H6	0.5446	0.5848	0.4774	0.038*
C7	0.6560 (5)	0.4652 (4)	0.5190 (3)	0.0475 (14)
H7A	0.7369	0.4404	0.5083	0.057*
H7B	0.6552	0.4995	0.5709	0.057*
C8	0.5740 (5)	0.3617 (4)	0.5195 (3)	0.0526 (14)
H8A	0.5003	0.3811	0.5464	0.063*
H8B	0.6121	0.3012	0.5489	0.063*
C9	0.5444 (5)	0.3191 (4)	0.4363 (3)	0.0486 (14)
C10	0.6638 (5)	0.3074 (4)	0.3954 (3)	0.0487 (14)
C11	0.6880 (5)	0.4191 (4)	0.3513 (2)	0.0381 (12)
H11	0.7664	0.4493	0.3659	0.046*
C12	0.5894 (4)	0.5006 (3)	0.3769 (2)	0.0307 (11)
C13	0.5508 (4)	0.5921 (4)	0.3191 (3)	0.0375 (12)
H13A	0.5434	0.5588	0.2671	0.045*
H13B	0.4728	0.6201	0.3344	0.045*
C14	0.6371 (4)	0.6909 (4)	0.3149 (2)	0.0354 (12)
H14A	0.6073	0.7466	0.2778	0.042*
H14B	0.7139	0.6643	0.2961	0.042*
C15	0.6524 (4)	0.7460 (3)	0.3957 (2)	0.0318 (11)
H15	0.5704	0.7580	0.4140	0.038*
C16	0.4857 (4)	0.4155 (4)	0.3910 (3)	0.0433 (14)
H16A	0.4223	0.4500	0.4216	0.052*
H16B	0.4530	0.3888	0.3415	0.052*
C17	0.8350 (5)	0.8739 (4)	0.3649 (3)	0.0427 (12)
C18	0.6337 (5)	0.9479 (4)	0.3449 (3)	0.0606 (17)
H18A	0.5518	0.9463	0.3616	0.091*
H18B	0.6386	0.9243	0.2909	0.091*
H18C	0.6643	1.0235	0.3499	0.091*
C19	0.8353 (4)	0.6305 (4)	0.4370 (3)	0.0418 (12)
H19A	0.8396	0.5977	0.3854	0.063*
H19B	0.8642	0.5770	0.4751	0.063*
H19C	0.8834	0.6977	0.4388	0.063*
C20	0.4736 (5)	0.2087 (4)	0.4388 (4)	0.0731 (19)
H20A	0.3994	0.2211	0.4657	0.110*
H20B	0.5189	0.1520	0.4662	0.110*
H20C	0.4580	0.1835	0.3861	0.110*
C21	0.9562 (6)	0.8432 (6)	0.2497 (4)	0.088 (2)
H21	1.0143	0.8872	0.2801	0.105*
C22	1.0009 (6)	0.7247 (7)	0.2372 (5)	0.110 (3)
H22A	1.0197	0.6911	0.2872	0.166*
H22B	1.0712	0.7265	0.2050	0.166*
H22C	0.9403	0.6806	0.2116	0.166*
C23	0.9293 (9)	0.9009 (7)	0.1744 (4)	0.131 (3)
H23A	0.9020	0.9766	0.1848	0.197*
H23B	0.8682	0.8598	0.1469	0.197*
H23C	1.0001	0.9039	0.1426	0.197*

	U11	U22	U33	U12	U13	U23
Br1	0.0767 (4)	0.0953 (5)	0.0501 (4)	0.0172 (4)	0.0068 (3)	−0.0263 (3)
O1	0.068 (3)	0.097 (3)	0.055 (2)	−0.043 (2)	0.011 (2)	−0.0233 (19)
O2	0.047 (3)	0.091 (3)	0.070 (3)	−0.024 (2)	−0.014 (2)	−0.016 (2)
O3	0.080 (3)	0.040 (2)	0.118 (4)	0.021 (2)	0.023 (3)	0.001 (2)
C1	0.038 (3)	0.035 (3)	0.043 (3)	−0.001 (2)	−0.009 (2)	−0.006 (2)
C2	0.049 (4)	0.041 (3)	0.059 (3)	−0.005 (2)	−0.006 (3)	−0.017 (2)
C3	0.062 (4)	0.062 (4)	0.038 (3)	−0.010 (3)	−0.004 (3)	−0.020 (3)
C4	0.052 (4)	0.050 (3)	0.036 (3)	−0.004 (3)	−0.005 (3)	−0.004 (2)
C5	0.028 (3)	0.038 (3)	0.031 (2)	0.006 (2)	−0.005 (2)	−0.0012 (19)
C6	0.028 (3)	0.033 (3)	0.035 (3)	0.009 (2)	0.004 (2)	0.002 (2)
C7	0.063 (4)	0.044 (3)	0.035 (3)	0.011 (3)	0.005 (3)	0.003 (2)
C8	0.067 (4)	0.040 (3)	0.051 (3)	0.001 (3)	0.013 (3)	0.010 (3)
C9	0.053 (4)	0.033 (3)	0.060 (4)	−0.012 (3)	0.017 (3)	−0.004 (3)
C10	0.057 (4)	0.033 (3)	0.056 (3)	0.008 (3)	0.007 (3)	−0.007 (3)
C11	0.037 (3)	0.043 (3)	0.034 (3)	−0.002 (2)	0.004 (3)	−0.006 (2)
C12	0.028 (3)	0.027 (3)	0.038 (3)	−0.001 (2)	0.004 (2)	−0.002 (2)
C13	0.036 (3)	0.041 (3)	0.036 (3)	−0.004 (2)	−0.006 (2)	−0.004 (2)
C14	0.037 (3)	0.036 (3)	0.033 (3)	0.000 (2)	−0.007 (2)	0.004 (2)
C15	0.024 (3)	0.033 (3)	0.037 (3)	−0.002 (2)	−0.008 (2)	−0.007 (2)
C16	0.033 (3)	0.038 (3)	0.058 (3)	−0.006 (2)	0.011 (2)	−0.007 (3)
C17	0.053 (4)	0.033 (3)	0.042 (3)	−0.011 (3)	−0.010 (3)	0.000 (2)
C18	0.063 (4)	0.040 (3)	0.079 (4)	0.004 (3)	−0.030 (3)	0.007 (3)
C19	0.027 (3)	0.046 (3)	0.051 (3)	−0.001 (3)	−0.007 (2)	0.006 (2)
C20	0.081 (5)	0.043 (4)	0.095 (5)	−0.014 (3)	0.025 (4)	0.004 (3)
C21	0.072 (4)	0.121 (6)	0.070 (5)	−0.053 (4)	0.033 (4)	−0.027 (5)
C22	0.078 (5)	0.155 (8)	0.097 (6)	−0.012 (5)	0.032 (4)	0.005 (6)
C23	0.186 (10)	0.113 (7)	0.094 (6)	−0.046 (6)	0.064 (6)	0.004 (5)

Br1—C11	1.957 (4)	C10—C11	1.539 (6)
O1—C17	1.314 (5)	C11—C12	1.528 (6)
O1—C21	1.467 (6)	C11—H11	0.9800
O2—C17	1.199 (5)	C12—C13	1.522 (6)
O3—C10	1.197 (6)	C12—C16	1.554 (6)
C1—C17	1.524 (6)	C13—C14	1.515 (6)
C1—C2	1.529 (6)	C13—H13A	0.9700
C1—C18	1.546 (6)	C13—H13B	0.9700
C1—C15	1.554 (6)	C14—C15	1.528 (6)
C2—C3	1.506 (7)	C14—H14A	0.9700
C2—H2A	0.9700	C14—H14B	0.9700
C2—H2B	0.9700	C15—H15	0.9800
C3—C4	1.541 (6)	C16—H16A	0.9700
C3—H3A	0.9700	C16—H16B	0.9700
C3—H3B	0.9700	C18—H18A	0.9600
C4—C5	1.536 (6)	C18—H18B	0.9600
C4—H4A	0.9700	C18—H18C	0.9600
C4—H4B	0.9700	C19—H19A	0.9600
C5—C19	1.536 (6)	C19—H19B	0.9600
C5—C15	1.551 (6)	C19—H19C	0.9600
C5—C6	1.567 (6)	C20—H20A	0.9600
C6—C7	1.532 (6)	C20—H20B	0.9600
C6—C12	1.562 (6)	C20—H20C	0.9600
C6—H6	0.9800	C21—C23	1.481 (10)
C7—C8	1.528 (6)	C21—C22	1.500 (9)
C7—H7A	0.9700	C21—H21	0.9800
C7—H7B	0.9700	C22—H22A	0.9600
C8—C9	1.537 (7)	C22—H22B	0.9600
C8—H8A	0.9700	C22—H22C	0.9600
C8—H8B	0.9700	C23—H23A	0.9600
C9—C10	1.514 (7)	C23—H23B	0.9600
C9—C16	1.523 (7)	C23—H23C	0.9600
C9—C20	1.526 (7)
C17—O1—C21	120.0 (4)	C13—C12—C6	110.0 (3)
C17—C1—C2	109.6 (4)	C11—C12—C6	110.3 (4)
C17—C1—C18	105.4 (4)	C16—C12—C6	107.3 (4)
C2—C1—C18	107.7 (4)	C14—C13—C12	113.3 (4)
C17—C1—C15	115.0 (4)	C14—C13—H13A	108.9
C2—C1—C15	108.6 (4)	C12—C13—H13A	108.9
C18—C1—C15	110.2 (4)	C14—C13—H13B	108.9
C3—C2—C1	114.5 (4)	C12—C13—H13B	108.9
C3—C2—H2A	108.6	H13A—C13—H13B	107.7
C1—C2—H2A	108.6	C13—C14—C15	110.9 (4)
C3—C2—H2B	108.6	C13—C14—H14A	109.4
C1—C2—H2B	108.6	C15—C14—H14A	109.4
H2A—C2—H2B	107.6	C13—C14—H14B	109.4
C2—C3—C4	111.4 (4)	C15—C14—H14B	109.4
C2—C3—H3A	109.3	H14A—C14—H14B	108.0
C4—C3—H3A	109.3	C14—C15—C5	111.1 (3)
C2—C3—H3B	109.3	C14—C15—C1	116.4 (4)
C4—C3—H3B	109.3	C5—C15—C1	115.7 (3)
H3A—C3—H3B	108.0	C14—C15—H15	103.9
C5—C4—C3	113.6 (4)	C5—C15—H15	103.9
C5—C4—H4A	108.8	C1—C15—H15	103.9
C3—C4—H4A	108.8	C9—C16—C12	103.8 (4)
C5—C4—H4B	108.8	C9—C16—H16A	111.0
C3—C4—H4B	108.8	C12—C16—H16A	111.0
H4A—C4—H4B	107.7	C9—C16—H16B	111.0
C4—C5—C19	108.0 (4)	C12—C16—H16B	111.0
C4—C5—C15	108.8 (3)	H16A—C16—H16B	109.0
C19—C5—C15	112.0 (4)	O2—C17—O1	121.7 (5)
C4—C5—C6	107.2 (4)	O2—C17—C1	126.1 (4)
C19—C5—C6	113.0 (3)	O1—C17—C1	112.1 (4)
C15—C5—C6	107.6 (3)	C1—C18—H18A	109.5
C7—C6—C12	111.7 (3)	C1—C18—H18B	109.5
C7—C6—C5	114.4 (4)	H18A—C18—H18B	109.5
C12—C6—C5	116.3 (3)	C1—C18—H18C	109.5
C7—C6—H6	104.3	H18A—C18—H18C	109.5
C12—C6—H6	104.3	H18B—C18—H18C	109.5
C5—C6—H6	104.3	C5—C19—H19A	109.5
C8—C7—C6	113.7 (4)	C5—C19—H19B	109.5
C8—C7—H7A	108.8	H19A—C19—H19B	109.5
C6—C7—H7A	108.8	C5—C19—H19C	109.5
C8—C7—H7B	108.8	H19A—C19—H19C	109.5
C6—C7—H7B	108.8	H19B—C19—H19C	109.5
H7A—C7—H7B	107.7	C9—C20—H20A	109.5
C7—C8—C9	112.7 (4)	C9—C20—H20B	109.5
C7—C8—H8A	109.1	H20A—C20—H20B	109.5
C9—C8—H8A	109.1	C9—C20—H20C	109.5
C7—C8—H8B	109.1	H20A—C20—H20C	109.5
C9—C8—H8B	109.1	H20B—C20—H20C	109.5
H8A—C8—H8B	107.8	O1—C21—C23	107.0 (6)
C10—C9—C16	102.5 (4)	O1—C21—C22	106.7 (5)
C10—C9—C20	113.2 (4)	C23—C21—C22	112.0 (6)
C16—C9—C20	115.3 (5)	O1—C21—H21	110.3
C10—C9—C8	105.2 (4)	C23—C21—H21	110.3
C16—C9—C8	108.3 (4)	C22—C21—H21	110.3
C20—C9—C8	111.5 (5)	C21—C22—H22A	109.5
O3—C10—C9	127.2 (5)	C21—C22—H22B	109.5
O3—C10—C11	125.2 (5)	H22A—C22—H22B	109.5
C9—C10—C11	107.6 (4)	C21—C22—H22C	109.5
C12—C11—C10	105.9 (4)	H22A—C22—H22C	109.5
C12—C11—Br1	114.7 (3)	H22B—C22—H22C	109.5
C10—C11—Br1	105.1 (3)	C21—C23—H23A	109.5
C12—C11—H11	110.3	C21—C23—H23B	109.5
C10—C11—H11	110.3	H23A—C23—H23B	109.5
Br1—C11—H11	110.3	C21—C23—H23C	109.5
C13—C12—C11	117.9 (4)	H23A—C23—H23C	109.5
C13—C12—C16	110.2 (4)	H23B—C23—H23C	109.5
C11—C12—C16	100.2 (3)

Puckering parameters	Ring A	Ring B	Ring C	Ring D
Q	0.540 (5)	0.563 (4)	0.641 (5)	0.441 (5)
θ	180.0 (5)	171.9 (4)	19.3 (4)
φ	314 (67)	98 (3)	243.1 (14)	134.2 (7)

Table 1

The puckering parameters (Å, °) for the six and five membered rings in compound I.

Puckering parameters	Ring A	Ring B	Ring C	Ring D
Q	0.540 (5)	0.563 (4)	0.641 (5)	0.441 (5)
θ	180.0 (5)	171.9 (4)	19.3 (4)
ϕ	314 (67)	98 (3)	243.1 (14)	134.2 (7)

Ring A atoms C1–C5/C15, B C5–C6/C12–C15, C C6–C9/C12/C16 and D C9–C12/C16.