(22E,24R)-5α-Ergosta-2,22-dien-6-one

Liu-qing Sheng; Fang Zeng; Fei Chen; Chun-nian Xia

doi:10.1107/S1600536811002388

. 2011 Jan 29;67(Pt 2):o507. doi: 10.1107/S1600536811002388

(22E,24R)-5α-Ergosta-2,22-dien-6-one

Liu-qing Sheng ^a,^*, Fang Zeng ^b, Fei Chen ^a, Chun-nian Xia ^b

PMCID: PMC3051496 PMID: 21523158

Abstract

In the title molecule, C₂₈H₄₄O, two six-membered rings have regular chair conformations, while the six-membered ring containing the C=C double bond exhibits a distorted chair conformation. The five-membered ring adopts an envelope conformation. In the crystal, weak intermolecular C—H⋯O interactions link molecules into chains along the b axis. The absolute configuration was assigned to correspond with that of the known chiral centres in a precursor molecule.

Related literature

For details of the synthesis, see: McMorris & Patil (1993 ▶). For the crystal structure of the related compound (22E,24R)-3α,5-cyclo-5α-ergosta-22-en-6-one, see: Sheng et al. (2011 ▶).

Experimental

Crystal data

C₂₈H₄₄O
M _r = 396.63
Monoclinic,
a = 9.812 (3) Å
b = 7.578 (2) Å
c = 16.130 (5) Å
β = 92.832 (4)°
V = 1197.8 (6) Å³
Z = 2
Mo Kα radiation
μ = 0.06 mm⁻¹
T = 123 K
0.58 × 0.34 × 0.33 mm

Data collection

Rigaku AFC10/Saturn724+ diffractometer
10906 measured reflections
2908 independent reflections
2598 reflections with I > 2σ(I)
R _int = 0.030

Refinement

R[F ² > 2σ(F ²)] = 0.042
wR(F ²) = 0.091
S = 1.03
2908 reflections
268 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.14 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2008 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811002388/cv5027sup1.cif

e-67-0o507-sup1.cif^{(25.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811002388/cv5027Isup2.hkl

e-67-0o507-Isup2.hkl^{(139.8KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1A⋯O1ⁱ	0.99	2.59	3.574 (3)	173

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Symmetry code: (i) Inline graphic .

Acknowledgments

This project was supported by the Science Foudation for Excellent Youth Scholars of the Department of Education of Zhejiang Province (grant No. G0901116050610). The authors acknowledge Professor Kai-bei Yu at the State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, for the data collection.

supplementary crystallographic information

Comment

In continuation of our structural study of brassinolide analogs (Sheng et al., 2011), we present here the crystal structure of the title compound, (I). In (I) (Fig. 1), ring A shows a distorted chair confirmation, and atoms C1, C2, C3 and C4 are coplanar with the r.m.s. deviation of 0.007 (1) Å for the C=C bond; atoms C5 and C10 deviate at 0.329 (4) Å and -0.423 (4) Å from this mean plane, respectively. Rings B and C have regular chair conformation each; while ring D has an envelope conformation. Weak intermolecular C—H···O interactions (Table 1) link the molecules related by translation along the axis b into chains.

Experimental

(22E,24R)-5α-Ergosta-2,22-dien-6-one was synthesized as a powder according to the known method (McMorris et al., 1993). Crystals of (I) suitable for structure analysis were obtained by slow evaporation from a mixture of acetone and 95% ethanol (volume proportion, 1:1) as colourless prisms.