PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. Aug 1, 2011; 67(Pt 8): o2122.
Published online Jul 23, 2011. doi:  10.1107/S1600536811028674
PMCID: PMC3213563
21-Hy­droxy­pregna-1,4-diene-3,20-dione
S. Yousuf,a* M. Bibi,a and M. I. Choudharya
aH.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
Correspondence e-mail: dr.sammer.yousuf/at/gmail.com
Received March 27, 2011; Accepted July 17, 2011.
Abstract
The title compound, C21H28O3, is a fungal transformed metabolite of decoxycorticosterone acetate, consisting of four fused rings A, B, C and D. Ring A is nearly planar, with a maximum deviation of 0.010 (3) Å from the least-squares plane, while the trans-fused rings B and C adopt chair conformations. The five-membered ring D is in an envelope conformation. The orientation of the side chain is stabilized by an intramolecular O—H(...)O hydrogen bond. In the crystal, adjecent mol­ecules are linked by C—H(...)O hydrogen bonds into extended zigzag chains along the a axis.
Related literature
The title compound was previously reported as the transformed metabolite of 11-de­oxy­corticosterone, see: Holland et al. (1995 [triangle]). For the crystal structure of the closely related compound corticosterone, see: Campsteyn et al. (1973 [triangle]) and for that of of 11-de­oxy­corticosterone, see: Dideberg et al. (1973 [triangle]); Dey et al. (1999 [triangle]).
An external file that holds a picture, illustration, etc.
Object name is e-67-o2122-scheme1.jpg Object name is e-67-o2122-scheme1.jpg
Crystal data
  • C21H28O3
  • M r = 328.43
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-67-o2122-efi1.jpg
  • a = 7.5882 (9) Å
  • b = 11.3506 (13) Å
  • c = 10.5462 (12) Å
  • β = 102.258 (2)°
  • V = 887.64 (18) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.08 mm−1
  • T = 298 K
  • 0.36 × 0.13 × 0.12 mm
Data collection
  • Bruker SMART APEX CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2000 [triangle]) T min = 0.972, T max = 0.990
  • 5287 measured reflections
  • 1739 independent reflections
  • 1467 reflections with I > 2σ(I)
  • R int = 0.026
Refinement
  • R[F 2 > 2σ(F 2)] = 0.038
  • wR(F 2) = 0.107
  • S = 0.95
  • 1739 reflections
  • 219 parameters
  • 1 restraint
  • H-atom parameters constrained
  • Δρmax = 0.14 e Å−3
  • Δρmin = −0.13 e Å−3
Data collection: SMART (Bruker, 2000 [triangle]); cell refinement: SAINT (Bruker, 2000 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 [triangle]).
Table 1
Table 1
Hydrogen-bond geometry (Å, °)
Supplementary Material
Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811028674/zb2014sup1.cif
Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811028674/zb2014Isup2.hkl
Additional supplementary materials: crystallographic information; 3D view; checkCIF report
supplementary crystallographic information
Comment
Structural modification of a substance as a result of enzymatic or metabolic activities of a living organism is known as biotransformation. In the current biotransformational study, the structural modification of a hypertension- inducing agent, 21-hydroxyprogesterone-21-acetate also known as 11-decoxycorticosterone acetate (DOCA), was investigated by using Cunninghamella elegans to obtain the title compound, 21-hydyoxypregna-1,4-diene-3,20-dione (I) as transformed metabolite, previously obtained as a result of the biotransformation of deoxycorticosteroid [Holland et al., 1995]. The title compound posseses four fused rings A (C1–C5/C10), B (C5–C10), C (C8–C9/C11–C14) and D (C13–C17). Trans fused rings B [Q= 0.568 (3) Å, θ = 177.5 (3)° and [var phi] = 259 (13)°]and C [Q= 0.576 (3) Å, θ = 173.4 (3)° and [var phi] = 97 (2)°] are in chair conformations, whereas ring D adopts [Q= 0.444 (3)Å and [var phi] = 10.6 (4)°] an envelope conformation. Ring A found Planar in geometery. The conformation of the acetyl side on C17 is stabilized by intramolecular O2–H1O2···O3 hydrogen bonding (Fig.1). In the crystal structure, the molecules are linked by C21–H22B···O1 interaction to form extended chains in a zigzag fashion (Fig. 2, Table-1). The bond dimensions are similar to those found in structurally related corticosterone [Campsteyn et al. 1973] and 11-deoxycorticosterone (Dey et al., 1999 and Dideberg et al., 1973).
Experimental
Fungal medium was prepared by dissolving following ingredients in distilled H2O (4.0 L): glucose (40.0 g), glycerol (40.0 ml), peptone (20.0 g), potassium dihydrogen phosphate (20.0 g), and sodium chloride (20.0 g), yeast extract (20.0 g) and equally distributed in 40 conical flasks (100 ml per flask). The mouth of flasks were covered with cotton wool and autoclaved at 121 °C. The mycelia of Cunninghamella elegans (NRRL 1392) were transferred into flasks and incubated at 26 °C for three days on rotary shaker. After growth of C. elegans, 21-hydroxyprogesterone-21-acetate (1 g m, dissolved in 20 ml acetone, 0.5 ml per flask) was distributed in all the flasks and allow to grow under same conditions for 14 days, followed by the filtration and extraction with dichloromethane. The extract was dried over anhydrous sodium sulfate and evaporated to obtained brown gumy material. The gummy material was fractionated by using silica gel column chromatography (gradient petroleum ether-acetone solvent system) to obtain several fractions. The fraction obtained 25%. was finally purified by using RP-HPLC (L-80, methanol-water 2:1, retention time 32 min.) to obtain title compound (15 mg).
Refinement
H atoms on methyl, methylene, methine and oxygen were positioned geometrically with C—H = 0.96 Å, 0.97 Å, 0.93 Å and O—H = 0.90 Å respectively, and constrained to ride on their parent atoms with Uiso(H)= 1.2Ueq(CH2, CH and OH) and 1.5Ueq(CH3). The absolute configuration was assumed to be that of corticosterone (Campsteyn et al., 1973) and 11-decoxycorticosterone (Diberg et al., 1973) & Dey et al., 1999) itself; 1538 Friedel pairs were merged.
Figures
Fig. 1.
Fig. 1.
The molecular structure of (I) with displacement ellipsoids drawn at 30% probability level. The dashed lines indicates the intramolecular hydrogen bonds. Hydrogen atoms are omitted for clarity.
Fig. 2.
Fig. 2.
The crystal packing of the title compound I. Only hydrogen atoms involved in hydrogen bonding are shown.
Crystal data
C21H28O3F(000) = 356
Mr = 328.43Dx = 1.229 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
a = 7.5882 (9) ÅCell parameters from 1378 reflections
b = 11.3506 (13) Åθ = 2.0–25.5°
c = 10.5462 (12) ŵ = 0.08 mm1
β = 102.258 (2)°T = 298 K
V = 887.64 (18) Å3Block, colourless
Z = 20.36 × 0.13 × 0.12 mm
Data collection
Bruker SMART APEX CCD area-detector diffractometer1739 independent reflections
Radiation source: fine-focus sealed tube1467 reflections with I > 2σ(I)
graphiteRint = 0.026
Detector resolution: 8.33 pixels mm-1θmax = 25.5°, θmin = 2.0°
ω scanh = −9→9
Absorption correction: multi-scan (SADABS; Bruker, 2000)k = −13→13
Tmin = 0.972, Tmax = 0.990l = −8→12
5287 measured reflections
Refinement
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.107H-atom parameters constrained
S = 0.95w = 1/[σ2(Fo2) + (0.0661P)2 + 0.090P] where P = (Fo2 + 2Fc2)/3
1739 reflections(Δ/σ)max < 0.001
219 parametersΔρmax = 0.14 e Å3
1 restraintΔρmin = −0.13 e Å3
Special details
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)
xyzUiso*/Ueq
O10.5573 (4)0.6466 (3)0.9017 (2)0.0945 (9)
O20.2867 (4)0.3644 (3)−0.2454 (2)0.0913 (9)
H1O20.18950.4096−0.27880.110*
O30.0016 (3)0.4543 (3)−0.1825 (2)0.0826 (9)
C10.5718 (4)0.6862 (3)0.5714 (3)0.0618 (9)
H1A0.65790.68700.52030.074*
C20.6286 (4)0.6644 (4)0.6965 (3)0.0685 (10)
H2A0.75040.64970.72890.082*
C30.5054 (4)0.6630 (3)0.7843 (3)0.0629 (8)
C40.3171 (4)0.6834 (3)0.7260 (3)0.0567 (8)
H4A0.23380.68200.77910.068*
C50.2577 (4)0.7042 (3)0.5998 (3)0.0454 (7)
C60.0594 (4)0.7164 (3)0.5427 (3)0.0587 (8)
H6A0.03510.79270.50110.070*
H6B−0.00860.71060.61070.070*
C70.0023 (4)0.6184 (3)0.4432 (3)0.0543 (8)
H7A0.01650.54280.48700.065*
H7B−0.12410.62790.40270.065*
C80.1135 (3)0.6197 (2)0.3392 (2)0.0374 (6)
H8A0.09150.69470.29240.045*
C90.3169 (3)0.6114 (2)0.4003 (2)0.0391 (6)
H9A0.33450.53600.44650.047*
C100.3807 (3)0.7096 (3)0.5053 (2)0.0441 (7)
C110.4304 (4)0.6053 (3)0.2956 (3)0.0520 (8)
H11A0.42620.68140.25320.062*
H11B0.55490.58980.33730.062*
C120.3677 (3)0.5108 (3)0.1926 (3)0.0496 (7)
H12A0.43740.51690.12570.059*
H12B0.38890.43350.23200.059*
C130.1683 (3)0.5243 (2)0.1315 (2)0.0374 (6)
C140.0637 (3)0.5206 (2)0.2418 (2)0.0371 (6)
H14A0.09890.44720.28940.045*
C15−0.1335 (4)0.5052 (3)0.1719 (3)0.0515 (7)
H15A−0.20190.46570.22730.062*
H15B−0.18890.58090.14600.062*
C16−0.1246 (4)0.4299 (3)0.0534 (3)0.0572 (8)
H16A−0.19280.4667−0.02480.069*
H16B−0.17480.35240.06170.069*
C170.0763 (3)0.4196 (3)0.0464 (2)0.0442 (6)
H17A0.12330.34600.08930.053*
C180.1330 (5)0.6381 (3)0.0533 (3)0.0561 (8)
H18A0.16030.70440.11060.084*
H18B0.00860.64120.00940.084*
H18C0.20800.6403−0.00940.084*
C190.3717 (5)0.8342 (3)0.4439 (3)0.0665 (9)
H19A0.39050.89250.51130.100*
H19B0.25540.84570.38810.100*
H19C0.46350.84150.39430.100*
C200.1086 (4)0.4173 (3)−0.0904 (3)0.0487 (7)
C210.2832 (5)0.3690 (4)−0.1131 (3)0.0672 (9)
H22A0.38170.4181−0.06850.081*
H22B0.30130.2903−0.07670.081*
Atomic displacement parameters (Å2)
U11U22U33U12U13U23
O10.104 (2)0.128 (2)0.0422 (12)0.0043 (19)−0.0030 (12)0.0045 (16)
O20.1074 (19)0.113 (2)0.0626 (15)0.0171 (18)0.0394 (14)−0.0185 (16)
O30.0769 (16)0.123 (2)0.0423 (11)0.0197 (15)0.0010 (11)−0.0080 (13)
C10.0358 (13)0.100 (3)0.0503 (17)−0.0076 (16)0.0113 (13)−0.0282 (18)
C20.0459 (16)0.100 (3)0.0544 (18)0.0067 (18)−0.0006 (15)−0.022 (2)
C30.072 (2)0.072 (2)0.0398 (15)−0.0014 (18)0.0019 (15)−0.0067 (16)
C40.0578 (16)0.079 (2)0.0381 (14)−0.0107 (16)0.0206 (13)−0.0129 (15)
C50.0430 (13)0.0529 (17)0.0418 (14)−0.0062 (12)0.0127 (12)−0.0123 (13)
C60.0418 (14)0.086 (2)0.0511 (17)0.0021 (15)0.0167 (13)−0.0210 (17)
C70.0346 (13)0.079 (2)0.0510 (16)−0.0073 (14)0.0138 (12)−0.0163 (16)
C80.0332 (12)0.0424 (14)0.0374 (12)0.0011 (11)0.0091 (10)−0.0030 (11)
C90.0343 (12)0.0466 (14)0.0378 (13)−0.0019 (11)0.0111 (11)−0.0039 (12)
C100.0390 (13)0.0617 (18)0.0338 (13)−0.0067 (12)0.0130 (11)−0.0076 (13)
C110.0353 (13)0.081 (2)0.0430 (14)−0.0117 (13)0.0161 (12)−0.0176 (15)
C120.0365 (14)0.072 (2)0.0435 (14)0.0019 (13)0.0164 (12)−0.0132 (15)
C130.0384 (13)0.0406 (14)0.0347 (12)0.0018 (11)0.0115 (11)−0.0028 (12)
C140.0350 (13)0.0384 (13)0.0383 (13)−0.0001 (10)0.0086 (11)0.0010 (11)
C150.0371 (14)0.0630 (19)0.0541 (16)−0.0042 (13)0.0093 (12)−0.0162 (15)
C160.0489 (15)0.0660 (19)0.0572 (17)−0.0109 (15)0.0126 (14)−0.0192 (16)
C170.0481 (14)0.0418 (14)0.0423 (14)−0.0010 (13)0.0089 (12)−0.0069 (13)
C180.083 (2)0.0443 (16)0.0436 (15)−0.0050 (15)0.0185 (14)−0.0006 (13)
C190.085 (2)0.061 (2)0.0556 (19)−0.0246 (18)0.0177 (17)−0.0115 (16)
C200.0550 (15)0.0485 (16)0.0416 (14)−0.0026 (14)0.0079 (13)−0.0127 (13)
C210.075 (2)0.074 (2)0.0573 (19)0.0070 (18)0.0232 (16)−0.0122 (17)
Geometric parameters (Å, °)
O1—C31.231 (4)C11—H11A0.9700
O2—C211.402 (4)C11—H11B0.9700
O2—H1O20.9067C12—C131.522 (4)
O3—C201.202 (3)C12—H12A0.9700
C1—C21.321 (4)C12—H12B0.9700
C1—C101.493 (4)C13—C181.525 (4)
C1—H1A0.9300C13—C141.542 (3)
C2—C31.450 (5)C13—C171.562 (4)
C2—H2A0.9300C14—C151.531 (3)
C3—C41.450 (4)C14—H14A0.9800
C4—C51.332 (4)C15—C161.528 (4)
C4—H4A0.9300C15—H15A0.9700
C5—C61.504 (4)C15—H15B0.9700
C5—C101.505 (4)C16—C171.546 (4)
C6—C71.527 (4)C16—H16A0.9700
C6—H6A0.9700C16—H16B0.9700
C6—H6B0.9700C17—C201.514 (4)
C7—C81.519 (4)C17—H17A0.9800
C7—H7A0.9700C18—H18A0.9600
C7—H7B0.9700C18—H18B0.9600
C8—C141.517 (3)C18—H18C0.9600
C8—C91.544 (3)C19—H19A0.9600
C8—H8A0.9800C19—H19B0.9600
C9—C111.539 (3)C19—H19C0.9600
C9—C101.574 (4)C20—C211.500 (4)
C9—H9A0.9800C21—H22A0.9700
C10—C191.551 (5)C21—H22B0.9700
C11—C121.528 (4)
C21—O2—H1O2100.3C13—C12—H12B109.4
C2—C1—C10125.3 (3)C11—C12—H12B109.4
C2—C1—H1A117.4H12A—C12—H12B108.0
C10—C1—H1A117.4C12—C13—C18111.0 (2)
C1—C2—C3121.5 (3)C12—C13—C14107.63 (19)
C1—C2—H2A119.2C18—C13—C14111.8 (2)
C3—C2—H2A119.2C12—C13—C17116.7 (2)
O1—C3—C2122.2 (3)C18—C13—C17109.15 (19)
O1—C3—C4121.8 (3)C14—C13—C17100.0 (2)
C2—C3—C4116.0 (2)C8—C14—C15119.2 (2)
C5—C4—C3123.1 (3)C8—C14—C13113.4 (2)
C5—C4—H4A118.4C15—C14—C13104.29 (19)
C3—C4—H4A118.4C8—C14—H14A106.4
C4—C5—C6120.9 (3)C15—C14—H14A106.4
C4—C5—C10122.9 (2)C13—C14—H14A106.4
C6—C5—C10116.1 (2)C16—C15—C14104.4 (2)
C5—C6—C7108.8 (2)C16—C15—H15A110.9
C5—C6—H6A109.9C14—C15—H15A110.9
C7—C6—H6A109.9C16—C15—H15B110.9
C5—C6—H6B109.9C14—C15—H15B110.9
C7—C6—H6B109.9H15A—C15—H15B108.9
H6A—C6—H6B108.3C15—C16—C17107.3 (2)
C8—C7—C6111.6 (2)C15—C16—H16A110.3
C8—C7—H7A109.3C17—C16—H16A110.3
C6—C7—H7A109.3C15—C16—H16B110.3
C8—C7—H7B109.3C17—C16—H16B110.3
C6—C7—H7B109.3H16A—C16—H16B108.5
H7A—C7—H7B108.0C20—C17—C16114.0 (2)
C14—C8—C7112.6 (2)C20—C17—C13114.7 (2)
C14—C8—C9108.66 (19)C16—C17—C13103.9 (2)
C7—C8—C9111.0 (2)C20—C17—H17A108.0
C14—C8—H8A108.1C16—C17—H17A108.0
C7—C8—H8A108.1C13—C17—H17A108.0
C9—C8—H8A108.1C13—C18—H18A109.5
C11—C9—C8111.5 (2)C13—C18—H18B109.5
C11—C9—C10113.7 (2)H18A—C18—H18B109.5
C8—C9—C10112.4 (2)C13—C18—H18C109.5
C11—C9—H9A106.2H18A—C18—H18C109.5
C8—C9—H9A106.2H18B—C18—H18C109.5
C10—C9—H9A106.2C10—C19—H19A109.5
C1—C10—C5111.2 (2)C10—C19—H19B109.5
C1—C10—C19108.0 (3)H19A—C19—H19B109.5
C5—C10—C19109.6 (2)C10—C19—H19C109.5
C1—C10—C9109.0 (2)H19A—C19—H19C109.5
C5—C10—C9107.2 (2)H19B—C19—H19C109.5
C19—C10—C9111.9 (2)O3—C20—C21117.8 (3)
C12—C11—C9113.8 (2)O3—C20—C17123.1 (3)
C12—C11—H11A108.8C21—C20—C17119.1 (3)
C9—C11—H11A108.8O2—C21—C20112.2 (3)
C12—C11—H11B108.8O2—C21—H22A109.2
C9—C11—H11B108.8C20—C21—H22A109.2
H11A—C11—H11B107.7O2—C21—H22B109.2
C13—C12—C11111.2 (2)C20—C21—H22B109.2
C13—C12—H12A109.4H22A—C21—H22B107.9
C11—C12—H12A109.4
C10—C1—C2—C3−0.9 (6)C10—C9—C11—C12−179.4 (2)
C1—C2—C3—O1−177.6 (4)C9—C11—C12—C1353.7 (3)
C1—C2—C3—C41.6 (6)C11—C12—C13—C1866.5 (3)
O1—C3—C4—C5178.4 (4)C11—C12—C13—C14−56.2 (3)
C2—C3—C4—C5−0.9 (5)C11—C12—C13—C17−167.6 (2)
C3—C4—C5—C6175.7 (3)C7—C8—C14—C1553.7 (3)
C3—C4—C5—C10−0.6 (5)C9—C8—C14—C15177.0 (2)
C4—C5—C6—C7−117.8 (3)C7—C8—C14—C13177.0 (2)
C10—C5—C6—C758.7 (4)C9—C8—C14—C13−59.6 (3)
C5—C6—C7—C8−56.2 (3)C12—C13—C14—C861.7 (3)
C6—C7—C8—C14178.0 (2)C18—C13—C14—C8−60.5 (3)
C6—C7—C8—C956.0 (3)C17—C13—C14—C8−175.93 (19)
C14—C8—C9—C1152.3 (3)C12—C13—C14—C15−167.1 (2)
C7—C8—C9—C11176.6 (2)C18—C13—C14—C1570.7 (3)
C14—C8—C9—C10−178.8 (2)C17—C13—C14—C15−44.7 (2)
C7—C8—C9—C10−54.4 (3)C8—C14—C15—C16161.2 (3)
C2—C1—C10—C5−0.5 (5)C13—C14—C15—C1633.4 (3)
C2—C1—C10—C19119.7 (4)C14—C15—C16—C17−8.4 (3)
C2—C1—C10—C9−118.5 (4)C15—C16—C17—C20−144.8 (3)
C4—C5—C10—C11.3 (4)C15—C16—C17—C13−19.3 (3)
C6—C5—C10—C1−175.1 (3)C12—C13—C17—C20−80.5 (3)
C4—C5—C10—C19−118.0 (3)C18—C13—C17—C2046.4 (3)
C6—C5—C10—C1965.5 (3)C14—C13—C17—C20163.8 (2)
C4—C5—C10—C9120.4 (3)C12—C13—C17—C16154.4 (2)
C6—C5—C10—C9−56.1 (3)C18—C13—C17—C16−78.8 (3)
C11—C9—C10—C1−59.5 (3)C14—C13—C17—C1638.7 (3)
C8—C9—C10—C1172.8 (2)C16—C17—C20—O321.1 (4)
C11—C9—C10—C5−179.9 (2)C13—C17—C20—O3−98.5 (3)
C8—C9—C10—C552.3 (3)C16—C17—C20—C21−160.2 (3)
C11—C9—C10—C1959.9 (3)C13—C17—C20—C2180.2 (3)
C8—C9—C10—C19−67.8 (3)O3—C20—C21—O2−5.9 (5)
C8—C9—C11—C12−51.2 (3)C17—C20—C21—O2175.3 (3)
Hydrogen-bond geometry (Å, °)
D—H···AD—HH···AD···AD—H···A
O2—H1O2···O30.911.982.602 (4)124
C21—H22B···O1i0.972.533.415 (5)152
Symmetry codes: (i) −x+1, y−1/2, −z+1.
Footnotes
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: ZB2014).
References
  • Bruker (2000). SADABS, SMART and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Campsteyn, H., Dupont, L., Dideberg, O. & Mandel, N. (1973). Acta Cryst. B29, 1726–1728.
  • Dey, R., Roychowdhury, S., Roychowdhury, P. & Righi, L. (1999). J. Chem. Crystallogr. 29, 1271–1275.
  • Dideberg, O., Campsteyn, H. & Dupont, L. (1973). Acta Cryst. B29, 103–112.
  • Holland, H. L., Nguyen, D. H. & Pearson, N. M. (1995). Steroids, 60, 646–649. [PubMed]
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]
Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of
International Union of Crystallography