(+)-3-Oxo-4-pregnene-20β-carboxyl­ic acid: catemeric hydrogen bonding in a steroidal keto acid

The title keto acid, (+)-23,24-dinor-3-oxo­chol-4-en-22-oic acid, C₂₂H₃₂O₃, forms carboxyl-to-ketone hydrogen-bonding catemers [O...O = 2.699 (4) Å and O—H...O = 173°], linking mol­ecules screw-related in b. The four mol­ecules in the cell form two parallel counter-directional chains, screw-related in a. Intermolecular C—H...O=C close contacts to different neighboring mol­ecules were found for the ketone and the acid.

S1. Comment

Our interest in the crystal structures of keto carboxylic acids concerns the molecular characteristics that control their five known hydrogen-bonding patterns. The acid dimers that characterize functionally unelaborated acids also predominate generally in keto acids. However, in non-racemates with significant conformational restrictions, the prevalence of acid-to-ketone catemers rises dramatically (Brunskill et al., 1999). Consequently, we have sought subject materials with terpenoid origins, and now report the crystal structure and hydrogen-bonding behavior of (I), the seventh in our series of steroidal keto acids.

Fig. 1 shows the asymmetric unit of (I) with its steroid numbering. Among the few conformational options present, the substituents at C20, which has the S configuration, are staggered with respect to those at C17, so that the C16—C17—C20—C21 torsion angle is 176.8 (3)°. The carboxyl plane coincides approximately with the C20—H20 bond, but the carboxyl group is turned with its carbonyl toward the bottom (α) face of the molecule [torsion angle C17—C20—C22—O2 = 73.8 (6)°]. In both of the steroids we have previously examined having this 23,24-dinor-22-oic acid side chain, the hydrogen-bonding patterns are very different from that in (I), and in both, the carboxyl carbonyl is oriented β (Lalancette et al., 1998; Thompson et al., 1999).

Complete or partial averaging of carboxyl C—O bond lengths and C—C—O angles by disorder is frequent in hydrogen-bonding dimers (Leiserowitz, 1976). However, catemers, hydrates and other hydrogen-bonding structures whose geometry precludes the usual carboxyl-disordering processes are highly ordered, as is found here. Our own survey of 56 keto acid structures which are not acid dimers gives average values of 1.20 (1) and 1.32 (2) Å, and 124.5 (14) and 112.7 (17)° for these lengths and angles, respectively, in accord with typical values of 1.21/1.31 Å and 123/112°, respectively, cited for highly ordered dimeric carboxyls (Borthwick, 1980). In (I), these lengths and angles are 1.185 (5)/1.311 (5) Å and 124.3 (4)/113.1 (4)°, respectively. No disorder was detected in the three methyl groups (C18, C19 and C21), which all adopt staggered arrangements.

Fig. 2 shows the packing of the cell and illustrates the two parallel hydrogen-bonding catemers created by the acid-to-ketone hydrogen bonding among molecules screw-related in b [O···O = 2.699 (4) Å and O—H···O = 173°]. The two chains are screw-related in a, and lie with their long axes parallel, but with opposite end-to-end orientation. In spite of a relatively slight change in molecular shape, this is dramatically different from the case of the 5-α-dihydro analog, whose hydrogen bonding is of the acid-to-acid type (Lalancette et al., 1998).

Within each molecule of (I), the dihedral angle between the carboxyl (C20/C22/O2/O3) and ketone planes (C2/C3/C4/O1) is 79.3 (2)°. However, for each hydrogen bond, the intermolecular dihedral angle between these two planes is 64.4 (3)°. We characterize the geometry of hydrogen bonding to carbonyls using a combination of the H···O═C angle and the H···O═C—C torsion angle. These describe the approach of the H atom to the O atom in terms of its deviation from, respectively, C═O axiality (ideal = 120°) and planarity with the carbonyl (ideal = 0°). In (I), these angles are 128 and -3°, respectively.

Intermolecular C—H···O═C close contacts to different neighboring molecules were found, involving O1 (2.69 Å to H21A) and O2 (2.64 Å to H6B). These distances lie within the 2.7 Å range we often employ for non-bonded C—H···O packing interactions (Steiner, 1997). Using compiled data for a large number of such contacts, Steiner & Desiraju (1998) find significant statistical directionality even as far out as 3.0 Å, and conclude that these are legitimately viewed as `weak hydrogen bonds', with a greater contribution to packing forces than simple van der Waals attractions.

We categorize subtypes of catemers by describing the relationship of adjacent molecules in the chains as homochiral (screw, translation) and heterochiral (glide). Among hydrogen-bonding catemers overall, the observed prevalence within the former grouping, appropriate to (I), is screw > translation, however this is our first observation of a screw-related steroidal catemer. Among the six previous steroid keto acids whose X-ray structures we have reported, all three of the cases displaying catemeric hydrogen bonding were translational.

The KBr IR spectrum of (I) displays C═O absorptions at 1723 (COOH) and 1649 cm^-1 (ketone), consistent with known shifts produced when hydrogen bonding is removed from carboxyl C═O and added to a ketone, plus an alkene absorption at 1614 cm^-1. In CHCl₃ solution, where dimers predominate, these peaks appear, normally, at 1707 and 1660 cm^-1, with the C═C peak at 1614 cm^-1 and a large carboxyl-dilution shoulder at ca 1732 cm^-1.

S2. Experimental

Compound (I), of known absolute stereochemistry and rotation, was purchased from Steraloids Inc., Newport, RI, USA, and recrystallized from 95% ethanol (m.p. 532 K).

S3. Refinement

All H atoms were found in electron-density difference maps but were placed in calculated positions and allowed to refine as riding models. C—H distances were 0.93–0.98 Å, and the O—H group was constrained to be 0.82 Å. A torsional parameter was refined for each methyl group.

Computing details

Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. A view of compound (I) with its steroid numbering. Displacement ellipsoids are set at the 20% probability level.
	Fig. 2. A packing diagram illustrating the screw-related parallel counter-directional pair of catemers passing through the cell in the b direction. All carbon-bound H atoms have been removed for clarity. Displacement ellipsoids are set at the 20% probability level.

(+)-4-Pregnen-3-one-20β-carboxylic acid

Crystal data

C22H32O3	Dx = 1.188 Mg m^−3
Mr = 344.48	Melting point: 532 K
Orthorhombic, P21212	Mo Kα radiation, λ = 0.71073 Å
a = 9.684 (3) Å	Cell parameters from 25 reflections
b = 27.325 (7) Å	θ = 2.4–9.7°
c = 7.281 (4) Å	µ = 0.08 mm^−1
V = 1926.7 (13) Å^3	T = 296 K
Z = 4	Hexagonal rod, colourless
F(000) = 752	0.31 × 0.15 × 0.10 mm

Data collection

Siemens P4 diffractometer	1453 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.072
Graphite monochromator	θmax = 25.0°, θmin = 2.2°
2θ/θ scans	h = −11→11
Absorption correction: numerical (Sheldrick, 1997)	k = −32→32
Tmin = 0.98, Tmax = 0.99	l = −8→8
7753 measured reflections	3 standard reflections every 97 reflections
1990 independent reflections	intensity decay: Variation < 3%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.050	H-atom parameters constrained
wR(F^2) = 0.114	w = 1/[σ^2(Fo^2) + (0.0512P)^2 + 0.1332P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.04
1990 reflections	Δρmax = 0.15 e Å^−3
227 parameters	Δρmin = −0.13 e Å^−3
0 restraints	Extinction correction: SHELXTL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0048 (13)

Special details

Experimental. crystal mounted on glass fiber using epoxy resin

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.1113 (3)	0.45528 (9)	0.8176 (4)	0.0703 (9)
O2	0.2437 (3)	0.89431 (12)	0.5441 (6)	0.1049 (14)
O3	0.4631 (3)	0.90123 (10)	0.4765 (5)	0.0790 (10)
C1	0.2259 (4)	0.57278 (12)	0.9705 (5)	0.0479 (10)
C2	0.2075 (5)	0.51783 (13)	1.0002 (5)	0.0558 (11)
C3	0.1814 (4)	0.49261 (12)	0.8234 (6)	0.0517 (10)
C4	0.2499 (4)	0.51243 (13)	0.6639 (5)	0.0515 (10)
C5	0.3257 (4)	0.55335 (12)	0.6638 (5)	0.0427 (9)
C6	0.4048 (5)	0.56829 (13)	0.4963 (5)	0.0544 (11)
C7	0.3782 (4)	0.62151 (13)	0.4436 (5)	0.0512 (10)
C8	0.4060 (4)	0.65541 (11)	0.6051 (4)	0.0357 (8)
C9	0.3171 (4)	0.64046 (11)	0.7702 (4)	0.0354 (8)
C10	0.3375 (4)	0.58592 (11)	0.8304 (5)	0.0374 (8)
C11	0.3295 (4)	0.67672 (11)	0.9282 (4)	0.0411 (9)
C12	0.3068 (4)	0.72992 (11)	0.8724 (4)	0.0383 (9)
C13	0.4006 (3)	0.74492 (12)	0.7139 (4)	0.0330 (8)
C14	0.3737 (3)	0.70812 (12)	0.5584 (4)	0.0352 (8)
C15	0.4401 (4)	0.73125 (13)	0.3902 (5)	0.0456 (10)
C16	0.4247 (4)	0.78633 (13)	0.4208 (5)	0.0456 (10)
C17	0.3632 (4)	0.79328 (12)	0.6146 (5)	0.0382 (8)
C18	0.5514 (4)	0.74581 (13)	0.7735 (5)	0.0461 (9)
C19	0.4832 (4)	0.57791 (13)	0.9136 (6)	0.0528 (10)
C20	0.4040 (4)	0.84230 (12)	0.6991 (5)	0.0521 (10)
C21	0.3384 (6)	0.85185 (16)	0.8871 (6)	0.0892 (17)
C22	0.3597 (5)	0.88193 (14)	0.5670 (7)	0.0598 (11)
H3A	0.4335	0.9171	0.3894	0.118*
H1A	0.2489	0.5879	1.0871	0.057*
H1B	0.1387	0.5865	0.9298	0.057*
H2A	0.2900	0.5045	1.0567	0.067*
H2B	0.1305	0.5122	1.0828	0.067*
H4A	0.2406	0.4956	0.5536	0.062*
H6A	0.3789	0.5473	0.3946	0.065*
H6B	0.5027	0.5638	0.5188	0.065*
H7A	0.4375	0.6305	0.3416	0.061*
H7B	0.2830	0.6252	0.4042	0.061*
H8A	0.5036	0.6529	0.6393	0.043*
H9A	0.2212	0.6428	0.7281	0.042*
H11A	0.4208	0.6737	0.9820	0.049*
H11B	0.2626	0.6681	1.0220	0.049*
H12A	0.2112	0.7344	0.8364	0.046*
H12B	0.3246	0.7509	0.9771	0.046*
H14A	0.2740	0.7092	0.5359	0.042*
H15A	0.3930	0.7212	0.2789	0.055*
H15B	0.5367	0.7222	0.3812	0.055*
H16A	0.3639	0.8003	0.3290	0.055*
H16B	0.5139	0.8023	0.4122	0.055*
H17A	0.2625	0.7937	0.6006	0.046*
H18A	0.5736	0.7157	0.8349	0.069*
H18B	0.5663	0.7728	0.8557	0.069*
H18C	0.6094	0.7495	0.6674	0.069*
H19A	0.4932	0.5443	0.9494	0.079*
H19B	0.4944	0.5985	1.0192	0.079*
H19C	0.5521	0.5859	0.8237	0.079*
H20A	0.5047	0.8434	0.7120	0.063*
H21A	0.3681	0.8831	0.9322	0.134*
H21B	0.3662	0.8267	0.9714	0.134*
H21C	0.2396	0.8517	0.8754	0.134*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.088 (2)	0.0385 (15)	0.084 (2)	−0.0176 (15)	0.014 (2)	−0.0114 (16)
O2	0.064 (2)	0.089 (2)	0.162 (4)	0.0206 (18)	0.010 (3)	0.065 (3)
O3	0.071 (2)	0.0652 (19)	0.101 (3)	0.0041 (16)	0.008 (2)	0.0381 (19)
C1	0.065 (3)	0.038 (2)	0.041 (2)	−0.0078 (18)	0.004 (2)	−0.0039 (17)
C2	0.069 (3)	0.044 (2)	0.054 (2)	−0.006 (2)	0.004 (2)	0.001 (2)
C3	0.058 (2)	0.031 (2)	0.066 (2)	−0.0019 (19)	0.002 (2)	−0.005 (2)
C4	0.069 (3)	0.039 (2)	0.046 (2)	−0.007 (2)	0.000 (2)	−0.0124 (18)
C5	0.050 (2)	0.038 (2)	0.039 (2)	0.0047 (18)	−0.0006 (19)	−0.0045 (17)
C6	0.074 (3)	0.042 (2)	0.048 (2)	0.001 (2)	0.013 (2)	−0.0139 (19)
C7	0.074 (3)	0.047 (2)	0.032 (2)	−0.005 (2)	0.012 (2)	−0.0037 (18)
C8	0.0389 (19)	0.0381 (18)	0.0302 (17)	−0.0016 (16)	0.0023 (17)	−0.0036 (16)
C9	0.0379 (19)	0.0347 (18)	0.0336 (17)	−0.0021 (15)	−0.0048 (17)	0.0001 (15)
C10	0.042 (2)	0.0328 (18)	0.0379 (18)	−0.0012 (16)	−0.0012 (18)	−0.0039 (16)
C11	0.053 (2)	0.0388 (19)	0.0312 (19)	−0.0030 (17)	0.000 (2)	−0.0012 (16)
C12	0.050 (2)	0.0351 (18)	0.0299 (18)	−0.0010 (16)	0.0017 (18)	−0.0016 (15)
C13	0.0323 (18)	0.0323 (17)	0.0345 (18)	0.0010 (15)	−0.0026 (16)	0.0006 (16)
C14	0.0330 (18)	0.0420 (19)	0.0307 (17)	−0.0001 (16)	0.0000 (17)	0.0006 (16)
C15	0.052 (2)	0.049 (2)	0.036 (2)	−0.0022 (17)	0.007 (2)	0.0057 (18)
C16	0.044 (2)	0.047 (2)	0.046 (2)	−0.0012 (17)	0.001 (2)	0.0096 (19)
C17	0.0326 (18)	0.0416 (19)	0.0405 (19)	−0.0002 (16)	−0.0036 (18)	0.0057 (17)
C18	0.047 (2)	0.046 (2)	0.045 (2)	0.0001 (18)	−0.0094 (19)	0.0028 (18)
C19	0.064 (3)	0.038 (2)	0.057 (2)	0.0086 (18)	−0.006 (2)	0.000 (2)
C20	0.060 (3)	0.040 (2)	0.057 (2)	−0.0024 (19)	−0.002 (2)	0.009 (2)
C21	0.150 (5)	0.049 (3)	0.069 (3)	−0.002 (3)	0.019 (4)	−0.012 (2)
C22	0.061 (3)	0.037 (2)	0.082 (3)	0.000 (2)	0.004 (3)	0.005 (2)

Geometric parameters (Å, º)

O1—C3	1.226 (4)	C1—H1B	0.9700
O2—C22	1.185 (5)	C2—H2A	0.9700
O3—C22	1.310 (5)	C2—H2B	0.9700
C1—C2	1.528 (5)	C4—H4A	0.9300
C1—C10	1.529 (5)	C6—H6A	0.9700
C2—C3	1.482 (5)	C6—H6B	0.9700
C3—C4	1.443 (5)	C7—H7A	0.9700
C4—C5	1.338 (5)	C7—H7B	0.9700
C5—C6	1.497 (5)	C8—H8A	0.9800
C5—C10	1.509 (5)	C9—H9A	0.9800
C6—C7	1.526 (5)	C11—H11A	0.9700
C7—C8	1.521 (5)	C11—H11B	0.9700
C8—C14	1.513 (4)	C12—H12A	0.9700
C8—C9	1.534 (4)	C12—H12B	0.9700
C9—C11	1.523 (4)	C14—H14A	0.9800
C9—C10	1.566 (4)	C15—H15A	0.9700
C10—C19	1.550 (5)	C15—H15B	0.9700
C11—C12	1.525 (4)	C16—H16A	0.9700
C12—C13	1.525 (5)	C16—H16B	0.9700
C13—C18	1.524 (5)	C17—H17A	0.9800
C13—C14	1.537 (4)	C18—H18A	0.9600
C13—C17	1.549 (4)	C18—H18B	0.9600
C14—C15	1.521 (5)	C18—H18C	0.9600
C15—C16	1.529 (5)	C19—H19A	0.9600
C16—C17	1.543 (5)	C19—H19B	0.9600
C17—C20	1.526 (5)	C19—H19C	0.9600
C20—C22	1.511 (6)	C20—H20A	0.9800
C20—C21	1.531 (6)	C21—H21A	0.9600
O3—H3A	0.8200	C21—H21B	0.9600
C1—H1A	0.9700	C21—H21C	0.9600
C2—C1—C10	114.1 (3)	C7—C6—H6B	109.2
C3—C2—C1	110.7 (3)	H6A—C6—H6B	107.9
O1—C3—C4	122.6 (4)	C8—C7—H7A	109.5
O1—C3—C2	120.7 (4)	C6—C7—H7A	109.5
C4—C3—C2	116.5 (3)	C8—C7—H7B	109.5
C5—C4—C3	124.5 (3)	C6—C7—H7B	109.5
C4—C5—C6	120.6 (3)	H7A—C7—H7B	108.1
C4—C5—C10	122.3 (3)	C14—C8—H8A	108.9
C6—C5—C10	117.1 (3)	C7—C8—H8A	108.9
C5—C6—C7	112.3 (3)	C9—C8—H8A	108.9
C8—C7—C6	110.8 (3)	C11—C9—H9A	105.6
C14—C8—C7	111.7 (3)	C8—C9—H9A	105.6
C14—C8—C9	108.3 (3)	C10—C9—H9A	105.6
C7—C8—C9	110.1 (3)	C9—C11—H11A	108.7
C11—C9—C8	112.0 (3)	C12—C11—H11A	108.7
C11—C9—C10	113.5 (3)	C9—C11—H11B	108.7
C8—C9—C10	113.7 (3)	C12—C11—H11B	108.7
C5—C10—C1	110.1 (3)	H11A—C11—H11B	107.6
C5—C10—C19	107.5 (3)	C13—C12—H12A	109.3
C1—C10—C19	110.5 (3)	C11—C12—H12A	109.3
C5—C10—C9	109.1 (3)	C13—C12—H12B	109.3
C1—C10—C9	108.7 (3)	C11—C12—H12B	109.3
C19—C10—C9	111.0 (3)	H12A—C12—H12B	107.9
C9—C11—C12	114.1 (3)	C8—C14—H14A	105.7
C13—C12—C11	111.8 (3)	C15—C14—H14A	105.7
C18—C13—C12	111.1 (3)	C13—C14—H14A	105.7
C18—C13—C14	112.5 (3)	C14—C15—H15A	110.9
C12—C13—C14	106.3 (2)	C16—C15—H15A	110.9
C18—C13—C17	110.1 (3)	C14—C15—H15B	110.8
C12—C13—C17	116.3 (3)	C16—C15—H15B	110.9
C14—C13—C17	100.1 (3)	H15A—C15—H15B	108.9
C8—C14—C15	119.3 (3)	C15—C16—H16A	110.3
C8—C14—C13	115.0 (3)	C17—C16—H16A	110.3
C15—C14—C13	104.5 (3)	C15—C16—H16B	110.3
C14—C15—C16	104.5 (3)	C17—C16—H16B	110.3
C15—C16—C17	107.0 (3)	H16A—C16—H16B	108.6
C20—C17—C16	112.1 (3)	C20—C17—H17A	106.9
C20—C17—C13	120.0 (3)	C16—C17—H17A	106.9
C16—C17—C13	103.4 (3)	C13—C17—H17A	106.9
C22—C20—C17	107.4 (3)	C13—C18—H18A	109.5
C22—C20—C21	109.2 (3)	C13—C18—H18B	109.5
C17—C20—C21	113.7 (3)	H18A—C18—H18B	109.5
O2—C22—O3	122.7 (4)	C13—C18—H18C	109.5
O2—C22—C20	124.3 (4)	H18A—C18—H18C	109.5
O3—C22—C20	113.0 (4)	H18B—C18—H18C	109.5
C22—O3—H3A	109.5	C10—C19—H19A	109.5
C2—C1—H1A	108.7	C10—C19—H19B	109.5
C10—C1—H1A	108.7	H19A—C19—H19B	109.5
C2—C1—H1B	108.7	C10—C19—H19C	109.5
C10—C1—H1B	108.7	H19A—C19—H19C	109.5
H1A—C1—H1B	107.6	H19B—C19—H19C	109.5
C3—C2—H2A	109.5	C22—C20—H20A	108.8
C1—C2—H2A	109.5	C17—C20—H20A	108.8
C3—C2—H2B	109.5	C21—C20—H20A	108.8
C1—C2—H2B	109.5	C20—C21—H21A	109.5
H2A—C2—H2B	108.1	C20—C21—H21B	109.5
C5—C4—H4A	117.7	H21A—C21—H21B	109.5
C3—C4—H4A	117.7	C20—C21—H21C	109.5
C5—C6—H6A	109.2	H21A—C21—H21C	109.5
C7—C6—H6A	109.2	H21B—C21—H21C	109.5
C5—C6—H6B	109.2
C10—C1—C2—C3	−54.7 (5)	C9—C11—C12—C13	−53.8 (4)
C1—C2—C3—O1	−150.0 (4)	C11—C12—C13—C18	−67.4 (4)
C1—C2—C3—C4	33.9 (5)	C11—C12—C13—C14	55.3 (4)
O1—C3—C4—C5	179.0 (4)	C11—C12—C13—C17	165.6 (3)
C2—C3—C4—C5	−5.0 (6)	C7—C8—C14—C15	−54.1 (4)
C3—C4—C5—C6	173.6 (4)	C9—C8—C14—C15	−175.5 (3)
C3—C4—C5—C10	−5.4 (6)	C7—C8—C14—C13	−179.4 (3)
C4—C5—C6—C7	129.9 (4)	C9—C8—C14—C13	59.2 (3)
C10—C5—C6—C7	−51.0 (5)	C18—C13—C14—C8	60.8 (4)
C5—C6—C7—C8	54.1 (5)	C12—C13—C14—C8	−61.0 (4)
C6—C7—C8—C14	−177.3 (3)	C17—C13—C14—C8	177.6 (3)
C6—C7—C8—C9	−56.9 (4)	C18—C13—C14—C15	−71.9 (4)
C14—C8—C9—C11	−51.3 (4)	C12—C13—C14—C15	166.3 (3)
C7—C8—C9—C11	−173.7 (3)	C17—C13—C14—C15	44.9 (3)
C14—C8—C9—C10	178.5 (3)	C8—C14—C15—C16	−161.9 (3)
C7—C8—C9—C10	56.1 (4)	C13—C14—C15—C16	−31.7 (4)
C4—C5—C10—C1	−14.5 (5)	C14—C15—C16—C17	5.6 (4)
C6—C5—C10—C1	166.4 (3)	C15—C16—C17—C20	152.7 (3)
C4—C5—C10—C19	105.9 (4)	C15—C16—C17—C13	22.1 (4)
C6—C5—C10—C19	−73.2 (4)	C18—C13—C17—C20	−47.6 (4)
C4—C5—C10—C9	−133.7 (4)	C12—C13—C17—C20	79.9 (4)
C6—C5—C10—C9	47.2 (4)	C14—C13—C17—C20	−166.2 (3)
C2—C1—C10—C5	44.2 (4)	C18—C13—C17—C16	78.2 (3)
C2—C1—C10—C19	−74.4 (4)	C12—C13—C17—C16	−154.4 (3)
C2—C1—C10—C9	163.6 (3)	C14—C13—C17—C16	−40.4 (3)
C11—C9—C10—C5	−179.0 (3)	C16—C17—C20—C22	55.8 (4)
C8—C9—C10—C5	−49.6 (4)	C13—C17—C20—C22	177.4 (3)
C11—C9—C10—C1	60.9 (4)	C16—C17—C20—C21	176.8 (3)
C8—C9—C10—C1	−169.6 (3)	C13—C17—C20—C21	−61.7 (5)
C11—C9—C10—C19	−60.8 (4)	C17—C20—C22—O2	73.8 (6)
C8—C9—C10—C19	68.7 (4)	C21—C20—C22—O2	−49.9 (6)
C8—C9—C11—C12	50.9 (4)	C17—C20—C22—O3	−105.3 (4)
C10—C9—C11—C12	−178.8 (3)	C21—C20—C22—O3	130.9 (4)