Download citation
Download citation
link to html
The title keto acid, C20H26O4, forms carboxyl-to-ketone hydrogen-bonding catemers [O...O = 2.653 (5) Å and O—H...O = 172 (5)°], linking translationally related mol­ecules via the A-ring ketone. The two mol­ecules in the cell form two parallel counter-directional chains, screw-related in b. A total of four intermolecular C—H...O=C close contacts was found, involving both ketone functions.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102009393/fr1378sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270102009393/fr1378Isup2.hkl
Contains datablock I

CCDC reference: 192980

Comment top

The single hydrogen-bonding donor and single acceptor of a carboxylic acid generate a high predominance of dimers in the absence of other functional groups. Our interest in the crystal structures of keto acids concerns the molecular characteristics that control their five known hydrogen-bonding patterns. While acid dimers also predominate generally in keto acids, in non-racemates with significant conformational restrictions, the prevalence of acid-to-ketone catemers rises dramatically (Brunskill et al., 1999). In studying this, we have sought subject materials with terpenoid origins, and now report the crystal structure and hydrogen-bonding behavior of (+)-3,11-dioxoandrost-4-ene-17β-carboxylic acid, (I), the eighth in our series of steroidal keto acids.

Fig. 1 shows the asymmetric unit of (I) with the steroid numbering. Among the few conformational options, both methyl groups adopt the expected staggered arrangements and the carboxyl carbonyl group is turned toward C16 so that C16 lies near the carboxyl plane [torsion angle C16—C17—C20—O3 = -6.8 (5)°]. In both of the 17β-carboxy keto steroids we have previously examined, the carboxyl group is similarly oriented (Brunskill et al., 1997; 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)/1.32 (2) Å and 124.5 (14)/112.7 (17)° for these lengths and angles, in accord with typical values of 1.21/1.31 Å and 123/112° cited for highly ordered dimeric carboxyls (Borthwick, 1980). In (I), these lengths and angles are 1.192 (4)/1.311 (5) Å and 124.8 (4)/112.0 (3)°. No significant disorder was detected in either methyl group.

Fig. 2 shows the packing in the cell and illustrates the two parallel catemers created by the acid-to-ketone hydrogen bonding among translationally related molecules. This hydrogen bonding involves only the remote A-ring ketone. The conjugated ketone would be both the more basic and more sterically accessible of the two. However, the choice here may be dictated more by the forces directing packing of the nonpolar portions of these generally planar molecules than by any such competition. The two chains are screw-related in b, and lie with their long axes parallel, but with opposite end-to-end orientation. This arrangement is identical to that seen in 3-oxoandrosta-1,4-diene-17β-carboxylic acid (Thompson et al., 1999), but differs markedly from that in 3-oxoandrost-4-ene-17β-carboxylic acid, whose chains diverge (Brunskill et al., 1997).

We categorize subtypes of catemers by describing the relationship of adjacent molecules in the chains as homochiral (screw and translation) and heterochiral (glide). For hydrogen-bonding catemers overall, the observed prevalence within the former grouping, appropriate to (I), is screw > translation. Among the seven steroid keto acids whose X-ray structures we have previously reported, four cases displayed catemeric hydrogen bonding. Of these four, three were translational, including both 17β-carboxy keto steroids (Brunskill et al., 1997; Thompson et al., 1999), and one involved a screw relationship. Translational catemers are not constrained to follow any crystallographic axis. Although molecules of (I) are aligned generally lengthwise along the c axis, this does not correspond to the hydrogen-bonding axis, but follows the [101] direction.

For each hydrogen bond [O···O = 2.653 (5) Å and O—H···O angle = 172 (5)°], the dihedral angle between the carboxyl (C17/C20/O2/O3) and ketone planes (C2'/C3'/C4'/O1') is 36.9 (2)°, identical with the intramolecular dihedral angle, since the chains are translational. In addition, we characterize the geometry of hydrogen bonding to carbonyls using a combination of the H···O C angle and the H···OC—C torsion angle. These describe the approach of the H atom to the O in terms of its deviation from, respectively, CO axiality (ideal = 120°) and planarity with the carbonyl (ideal = 0°). In (I), these angles are 136 (2) and -6(3)°, respectively.

A total of four intermolecular C—H···OC close contacts to neighboring molecules was found for both ketones (see Table 2), all lying within the 2.7 Å range we normally 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.

The KBr IR spectrum of (I) displays CO absorptions at 1726 (COOH) and 645 cm-1 (enone), consistent with known shifts produced when hydrogen-bonding is, respectively, removed from carboxyl CO and added to a ketone, plus a peak at 1704 cm-1 for the 11-oxo group. In CHCl3 solution, where dimers predominate, the acid and 11-oxo absorptions merge into a single broad peak at 1705 cm-1, with a carboxyl-dilution shoulder at ca 1745 cm-1. The enone peak appears, normally, at 1664 cm-1, revealing a CC peak at 1616 cm-1, seen in the KBr spectrum only as a slight shoulder.

Experimental top

11β,21-Dihydroxy-4-pregnene-3,20-dione of known absolute stereochemistry was purchased from Steraloids Inc., Newport, Rhode Island, USA, and oxidatively cleaved by NaIO4 in aqueous dioxane. Jones oxidation of the crude product provided compound (I), of known rotation (Mason et al., 1937). Crystals suitable for X-ray analysiswere produced from acetone (m.p. 543 K).

Refinement top

All H atoms were found in electron-density difference maps but were placed in calculated positions and allowed to refine as riding models, except for the hydroxyl H atom, whose positional and displacement parameters were all allowed to refine. The vinyl H atom was fixed at a distance of 0.93 Å, the methine H atoms at 0.98 Å, the methylene H atoms at 0.97 Å, and the methyl H atoms at 0.96 Å from their respective C atoms. The Uiso value for each methylene H atom was fixed at 120% of the isotropic displacement parameter of its C atom and for each methyl H atom, at 150% of that of its C atom. The absolute configuration of (I) was not determined (see Experimental); Friedel pairs were averaged.

Computing details top

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 top
[Figure 1] Fig. 1. View of compound (I) with the steroid numbering. Displacement ellipsoids are set at the 20% probability level.
[Figure 2] Fig. 2. A packing diagram with extracellular molecules, included to illustrate the parallel screw-related pair of catemers passing counterdirectionally through the cell. All C-bound H atoms have been removed for clarity. Displacement ellipsoids are set at the 20% probability level.
'(+)-3,11-Dioxoandrost-4-ene-17β-carboxylic acid' top
Crystal data top
C20H26O4Dx = 1.225 Mg m3
Mr = 330.41Melting point: 543 K
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
a = 6.699 (2) ÅCell parameters from 36 reflections
b = 11.409 (3) Åθ = 3.5–11.3°
c = 11.764 (3) ŵ = 0.08 mm1
β = 94.98 (2)°T = 296 K
V = 895.7 (4) Å3Parallelepiped, colourless
Z = 20.38 × 0.27 × 0.14 mm
F(000) = 356
Data collection top
Siemens P4
diffractometer
1245 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.057
Graphite monochromatorθmax = 25.0°, θmin = 2.5°
2θ/θ scansh = 77
Absorption correction: numerical
(Sheldrick, 1997)
k = 1313
Tmin = 0.97, Tmax = 0.99l = 1313
3582 measured reflections3 standard reflections every 97 reflections
1657 independent reflections intensity decay: variation <3.5%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.041H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.085 w = 1/[σ2(Fo2) + (0.0103P)2 + 0.057P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max < 0.001
1658 reflectionsΔρmax = 0.11 e Å3
222 parametersΔρmin = 0.11 e Å3
1 restraintExtinction correction: SHELXTL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0187 (17)
Crystal data top
C20H26O4V = 895.7 (4) Å3
Mr = 330.41Z = 2
Monoclinic, P21Mo Kα radiation
a = 6.699 (2) ŵ = 0.08 mm1
b = 11.409 (3) ÅT = 296 K
c = 11.764 (3) Å0.38 × 0.27 × 0.14 mm
β = 94.98 (2)°
Data collection top
Siemens P4
diffractometer
1245 reflections with I > 2σ(I)
Absorption correction: numerical
(Sheldrick, 1997)
Rint = 0.057
Tmin = 0.97, Tmax = 0.993 standard reflections every 97 reflections
3582 measured reflections intensity decay: variation <3.5%
1657 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0411 restraint
wR(F2) = 0.085H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.11 e Å3
1658 reflectionsΔρmin = 0.11 e Å3
222 parameters
Special details top

Experimental. Crystal mounted on glass fiber using epoxy resin

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
xyzUiso*/Ueq
O10.5654 (5)0.4336 (3)1.0660 (3)0.1145 (12)
O20.0837 (4)0.4693 (2)0.6111 (2)0.0634 (7)
O30.0381 (5)0.6385 (3)0.1058 (2)0.0923 (9)
O40.0811 (6)0.4650 (3)0.1819 (3)0.0926 (9)
C10.2202 (6)0.4289 (3)0.8147 (3)0.0610 (10)
C20.2677 (7)0.4239 (4)0.9436 (3)0.0769 (12)
C30.4718 (7)0.4692 (4)0.9789 (3)0.0731 (11)
C40.5462 (6)0.5626 (3)0.9109 (3)0.0637 (9)
C50.4484 (5)0.6036 (3)0.8153 (3)0.0508 (9)
C60.5225 (5)0.7108 (3)0.7567 (3)0.0592 (9)
C70.5276 (5)0.6919 (3)0.6284 (3)0.0581 (10)
C80.3268 (4)0.6520 (3)0.5721 (3)0.0438 (7)
C90.2582 (4)0.5393 (2)0.6326 (3)0.0432 (7)
C100.2503 (5)0.5523 (3)0.7644 (3)0.0460 (8)
C110.0711 (5)0.4878 (3)0.5674 (3)0.0475 (8)
C120.0858 (5)0.4657 (3)0.4422 (3)0.0541 (9)
C130.1393 (5)0.5809 (3)0.3855 (3)0.0460 (8)
C140.3369 (4)0.6266 (3)0.4454 (3)0.0478 (8)
C150.3973 (5)0.7249 (3)0.3673 (3)0.0591 (10)
C160.3272 (6)0.6814 (4)0.2462 (3)0.0748 (11)
C170.1947 (5)0.5736 (3)0.2598 (3)0.0611 (10)
C180.0349 (5)0.6666 (3)0.3925 (3)0.0515 (8)
C190.0792 (5)0.6361 (4)0.7939 (3)0.0639 (10)
C200.0140 (6)0.5647 (4)0.1736 (3)0.0666 (10)
H40.212 (8)0.458 (5)0.133 (4)0.126 (18)*
H1A0.08230.40480.79620.073*
H1B0.30560.37370.77910.073*
H2A0.16960.47000.98010.092*
H2B0.25760.34340.96920.092*
H4A0.66920.59600.93510.076*
H6A0.65620.73000.78980.071*
H6B0.43560.77650.76970.071*
H7A0.56570.76460.59340.070*
H7B0.62840.63360.61540.070*
H80.22790.71400.58040.053*
H90.36420.48170.62360.052*
H12A0.04110.43650.40740.065*
H12B0.18800.40740.43210.065*
H140.43570.56390.44040.057*
H15A0.54120.73700.37540.071*
H15B0.33130.79780.38410.071*
H16A0.25180.74230.20390.090*
H16B0.44170.66080.20520.090*
H170.27720.50350.25240.073*
H18A0.06950.67110.46990.077*
H18B0.14860.63960.34430.077*
H18C0.00410.74280.36770.077*
H19A0.07860.64200.87530.096*
H19B0.04720.60560.76220.096*
H19C0.10050.71220.76250.096*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.133 (3)0.132 (3)0.0690 (19)0.045 (2)0.0405 (19)0.036 (2)
O20.0581 (15)0.0667 (16)0.0651 (15)0.0216 (14)0.0031 (12)0.0022 (13)
O30.115 (2)0.089 (2)0.0677 (17)0.002 (2)0.0210 (16)0.0205 (18)
O40.121 (3)0.081 (2)0.0706 (19)0.017 (2)0.0248 (18)0.0159 (16)
C10.074 (2)0.062 (2)0.047 (2)0.015 (2)0.0030 (18)0.0010 (18)
C20.100 (3)0.080 (3)0.051 (2)0.026 (2)0.009 (2)0.002 (2)
C30.090 (3)0.088 (3)0.040 (2)0.018 (3)0.003 (2)0.000 (2)
C40.067 (2)0.073 (2)0.049 (2)0.017 (2)0.0035 (18)0.004 (2)
C50.0543 (19)0.054 (2)0.045 (2)0.0014 (17)0.0099 (16)0.0106 (15)
C60.054 (2)0.058 (2)0.064 (2)0.0145 (19)0.0030 (18)0.0010 (18)
C70.053 (2)0.061 (2)0.059 (2)0.0069 (18)0.0024 (18)0.0082 (17)
C80.0394 (16)0.0426 (18)0.0497 (17)0.0028 (15)0.0051 (14)0.0022 (14)
C90.0451 (17)0.0393 (16)0.0451 (17)0.0054 (16)0.0033 (14)0.0025 (14)
C100.0508 (19)0.0456 (18)0.0419 (17)0.0086 (17)0.0057 (15)0.0036 (15)
C110.054 (2)0.0344 (17)0.053 (2)0.0070 (17)0.0001 (16)0.0047 (15)
C120.064 (2)0.0429 (18)0.054 (2)0.0012 (18)0.0051 (17)0.0015 (17)
C130.0488 (18)0.0445 (19)0.0445 (18)0.0088 (16)0.0037 (15)0.0070 (15)
C140.0391 (17)0.0505 (18)0.054 (2)0.0119 (15)0.0060 (15)0.0064 (17)
C150.046 (2)0.071 (2)0.062 (2)0.0029 (19)0.0102 (18)0.0155 (18)
C160.075 (3)0.088 (3)0.063 (2)0.007 (2)0.016 (2)0.019 (2)
C170.068 (2)0.067 (2)0.049 (2)0.018 (2)0.0062 (17)0.0003 (18)
C180.0437 (18)0.0492 (18)0.061 (2)0.0043 (16)0.0016 (16)0.0034 (16)
C190.053 (2)0.074 (2)0.066 (2)0.002 (2)0.0134 (18)0.012 (2)
C200.090 (3)0.067 (2)0.043 (2)0.012 (3)0.005 (2)0.003 (2)
Geometric parameters (Å, º) top
O1—C31.223 (5)O4—H41.01 (6)
O2—C111.215 (4)C1—H1A0.9700
O3—C201.192 (4)C1—H1B0.9700
O4—C201.311 (5)C2—H2A0.9700
C1—C21.524 (5)C2—H2B0.9700
C1—C101.547 (5)C4—H4A0.9300
C2—C31.487 (6)C6—H6A0.9700
C3—C41.447 (5)C6—H6B0.9700
C4—C51.336 (5)C7—H7A0.9700
C5—C61.509 (5)C7—H7B0.9700
C5—C101.525 (4)C8—H80.9800
C6—C71.528 (5)C9—H90.9800
C7—C81.517 (4)C12—H12A0.9700
C8—C141.526 (4)C12—H12B0.9700
C8—C91.557 (4)C14—H140.9800
C9—C111.528 (4)C15—H15A0.9700
C9—C101.563 (4)C15—H15B0.9700
C10—C191.555 (5)C16—H16A0.9700
C11—C121.507 (4)C16—H16B0.9700
C12—C131.530 (4)C17—H170.9800
C13—C181.530 (4)C18—H18A0.9600
C13—C141.536 (5)C18—H18B0.9600
C13—C171.558 (4)C18—H18C0.9600
C14—C151.527 (4)C19—H19A0.9600
C15—C161.542 (5)C19—H19B0.9600
C16—C171.533 (5)C19—H19C0.9600
C17—C201.514 (5)
C2—C1—C10113.1 (3)C1—C2—H2B109.2
C3—C2—C1111.9 (3)H2A—C2—H2B107.9
O1—C3—C4122.1 (4)C5—C4—H4A118.1
O1—C3—C2120.7 (4)C3—C4—H4A118.1
C4—C3—C2117.0 (4)C5—C6—H6A109.2
C5—C4—C3123.8 (3)C7—C6—H6A109.2
C4—C5—C6120.8 (3)C5—C6—H6B109.2
C4—C5—C10122.9 (3)C7—C6—H6B109.2
C6—C5—C10116.2 (3)H6A—C6—H6B107.9
C5—C6—C7112.0 (3)C8—C7—H7A109.2
C8—C7—C6112.3 (3)C6—C7—H7A109.2
C7—C8—C14111.8 (2)C8—C7—H7B109.2
C7—C8—C9109.6 (3)C6—C7—H7B109.2
C14—C8—C9109.2 (3)H7A—C7—H7B107.9
C11—C9—C8110.5 (3)C7—C8—H8108.7
C11—C9—C10115.9 (3)C14—C8—H8108.7
C8—C9—C10114.3 (2)C9—C8—H8108.7
C5—C10—C1109.7 (3)C11—C9—H9105.0
C5—C10—C19108.0 (3)C8—C9—H9105.0
C1—C10—C19110.5 (3)C10—C9—H9105.0
C5—C10—C9108.9 (2)C11—C12—H12A110.0
C1—C10—C9108.1 (3)C13—C12—H12A110.0
C19—C10—C9111.7 (3)C11—C12—H12B110.0
O2—C11—C12121.0 (3)C13—C12—H12B110.0
O2—C11—C9123.2 (3)H12A—C12—H12B108.3
C12—C11—C9115.7 (3)C8—C14—H14106.5
C11—C12—C13108.7 (3)C15—C14—H14106.5
C12—C13—C18108.4 (3)C13—C14—H14106.5
C12—C13—C14108.5 (3)C14—C15—H15A110.9
C18—C13—C14112.9 (3)C16—C15—H15A110.9
C12—C13—C17116.9 (3)C14—C15—H15B110.9
C18—C13—C17109.3 (3)C16—C15—H15B110.9
C14—C13—C17100.8 (2)H15A—C15—H15B108.9
C8—C14—C15119.0 (3)C17—C16—H16A110.3
C8—C14—C13113.8 (2)C15—C16—H16A110.3
C15—C14—C13103.6 (3)C17—C16—H16B110.3
C14—C15—C16104.1 (3)C15—C16—H16B110.3
C17—C16—C15107.1 (3)H16A—C16—H16B108.5
C20—C17—C16114.9 (3)C20—C17—H17108.0
C20—C17—C13113.4 (3)C16—C17—H17108.0
C16—C17—C13104.1 (3)C13—C17—H17108.0
O3—C20—O4123.2 (4)C13—C18—H18A109.5
O3—C20—C17124.8 (4)C13—C18—H18B109.5
O4—C20—C17112.0 (3)H18A—C18—H18B109.5
C20—O4—H4115 (3)C13—C18—H18C109.5
C2—C1—H1A109.0H18A—C18—H18C109.5
C10—C1—H1A109.0H18B—C18—H18C109.5
C2—C1—H1B109.0C10—C19—H19A109.5
C10—C1—H1B109.0C10—C19—H19B109.5
H1A—C1—H1B107.8H19A—C19—H19B109.5
C3—C2—H2A109.2C10—C19—H19C109.5
C1—C2—H2A109.2H19A—C19—H19C109.5
C3—C2—H2B109.2H19B—C19—H19C109.5
C10—C1—C2—C353.9 (5)C8—C9—C11—C1253.0 (3)
C1—C2—C3—O1151.9 (4)C10—C9—C11—C12174.9 (3)
C1—C2—C3—C432.8 (5)O2—C11—C12—C13120.3 (3)
O1—C3—C4—C5179.9 (4)C9—C11—C12—C1357.1 (4)
C2—C3—C4—C54.8 (6)C11—C12—C13—C1865.3 (4)
C3—C4—C5—C6172.4 (3)C11—C12—C13—C1457.7 (3)
C3—C4—C5—C102.8 (6)C11—C12—C13—C17170.7 (3)
C4—C5—C6—C7132.6 (4)C7—C8—C14—C1559.7 (4)
C10—C5—C6—C751.8 (4)C9—C8—C14—C15178.9 (3)
C5—C6—C7—C854.3 (4)C7—C8—C14—C13177.6 (3)
C6—C7—C8—C14176.7 (3)C9—C8—C14—C1356.2 (3)
C6—C7—C8—C955.5 (4)C12—C13—C14—C860.8 (3)
C7—C8—C9—C11172.2 (3)C18—C13—C14—C859.4 (3)
C14—C8—C9—C1149.5 (3)C17—C13—C14—C8175.8 (3)
C7—C8—C9—C1054.9 (3)C12—C13—C14—C15168.4 (3)
C14—C8—C9—C10177.6 (3)C18—C13—C14—C1571.4 (3)
C4—C5—C10—C117.8 (4)C17—C13—C14—C1545.1 (3)
C6—C5—C10—C1166.8 (3)C8—C14—C15—C16162.6 (3)
C4—C5—C10—C19102.7 (4)C13—C14—C15—C1635.0 (3)
C6—C5—C10—C1972.7 (3)C14—C15—C16—C1710.9 (4)
C4—C5—C10—C9135.8 (3)C15—C16—C17—C20141.5 (3)
C6—C5—C10—C948.8 (4)C15—C16—C17—C1316.8 (4)
C2—C1—C10—C545.4 (4)C12—C13—C17—C2079.4 (4)
C2—C1—C10—C1973.6 (4)C18—C13—C17—C2044.2 (4)
C2—C1—C10—C9163.9 (3)C14—C13—C17—C20163.3 (3)
C11—C9—C10—C5179.5 (3)C12—C13—C17—C16155.0 (3)
C8—C9—C10—C550.2 (3)C18—C13—C17—C1681.4 (3)
C11—C9—C10—C160.5 (4)C14—C13—C17—C1637.7 (3)
C8—C9—C10—C1169.3 (3)C16—C17—C20—O36.9 (5)
C11—C9—C10—C1961.3 (3)C13—C17—C20—O3112.7 (4)
C8—C9—C10—C1969.0 (3)C16—C17—C20—O4173.3 (3)
C8—C9—C11—O2124.3 (3)C13—C17—C20—O467.1 (4)
C10—C9—C11—O27.8 (4)

Experimental details

Crystal data
Chemical formulaC20H26O4
Mr330.41
Crystal system, space groupMonoclinic, P21
Temperature (K)296
a, b, c (Å)6.699 (2), 11.409 (3), 11.764 (3)
β (°) 94.98 (2)
V3)895.7 (4)
Z2
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.38 × 0.27 × 0.14
Data collection
DiffractometerSiemens P4
diffractometer
Absorption correctionNumerical
(Sheldrick, 1997)
Tmin, Tmax0.97, 0.99
No. of measured, independent and
observed [I > 2σ(I)] reflections
3582, 1657, 1245
Rint0.057
(sin θ/λ)max1)0.594
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.041, 0.085, 1.07
No. of reflections1658
No. of parameters222
No. of restraints1
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.11, 0.11

Computer programs: XSCANS (Siemens, 1996), XSCANS, SHELXTL (Sheldrick, 1997), SHELXTL.

Selected geometric parameters (Å, º) top
O3—C201.192 (4)O4—C201.311 (5)
O3—C20—C17124.8 (4)O4—C20—C17112.0 (3)
 

Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds