Crystallography Reports, Vol. 46, No. 3, 2001, pp. 415–418. From Kristallografiya, Vol. 46, No. 3, 2001, pp. 465–468.Original English Text Copyright © 2001 by Rajnikant, V. Gupta, Firoz, Shafiullah, R. Gupta.

STRUCTURE OF ORGANIC COMPOUNDS

Structure Analysis of 3b-Chloro-6-Nitrocholest-5-ene1 Rajnikant*2, V. K. Gupta*, J. Firoz**, Shafiullah**, and R. Gupta*

* X-ray Crystallography Laboratory, Post-Graduate Department of Physics, University of Jammu, Jammu Tawi, 180 006 India

** Steroid Research Laboratory, Department of Chemistry, Aligarh Muslim University, Aligarh, 202 002 India

e-mail: rajni_kant_verma@hotmail.comReceived March 15, 2000; in final form, August 8, 2000

Abstract—The crystal structure of the title compound (C27H44NO2Cl) is determined by X-ray structure anal-ysis. The compound crystallizes in the orthorhombic space group P212121 with the unit cell parameters a =7.207(1) Å, b = 11.292(1) Å, and c = 32.373(5) Å. The structure is solved by direct methods and refined to R =0.060. Rings A and C exist in the chair conformation. Ring B adopts a half-chair conformation, and ring D is a13β envelope. The A/B ring junction is quasi-trans, while the B/C and C/D ring systems are trans fused aboutthe C(8)–C(9) and C(13)–C(14) bonds, respectively. Molecules are linked together by the C–H···O hydrogenbonds. © 2001 MAIK “Nauka/Interperiodica”.

12 INTRODUCTIONThe X-ray structure analysis of the title compound

is a continuation of our crystallographic investigationson steroids [1–6].

EXPERIMENTALSynthesis. The compound to be studied was pre-

pared as follows. Sodium nitrite NaNO2 (3.0 g) wasgradually (over a period of 3 h) added to a well-stirredmixture of 3β-chloro-cholest-5-ene (12 g), glacial ace-tic acid (80 ml), and nitric acid (25 ml, d = 1.52 g/cm3)at a temperature below 20°C. After the addition ofsodium nitrite, the mixture was further stirred about1 h. Then, ice cold water (200 ml) was added and theyellowish precipitate thus obtained was filtered off anddried in air. Recrystallization from methanol gave 3β-chloro-6-nitrocholest-5-ene (8.5 g) as needles (mp =424–425 K). The chemical structure (Fig. 1) was deter-mined on the basis of IR, UV, NMR, and mass spectraldata [7].

X-ray diffraction analysis. Three-dimensionalintensity data for the steroidal molecule were collectedon an Enraf–Nonius CAD4 diffractometer (CuKα radi-ation, ω/2θ scan mode). Two strong reflections moni-tored every 100 reflections showed no significantchange in the intensity, thus confirming the stability ofthe crystal toward X-rays. A total of 2247 reflectionswere measured, of which 1789 (0 < h < 7, 0 < k < 13,0 < l < 37) reflections were treated as observed. Thedata were corrected for Lorentz and polarizationeffects. No absorption and extinction corrections wereapplied.

1 This article was submitted by the authors in English.2 Author for correspondence.

1063-7745/01/4603- $21.00 © 20415

The structure has been solved by direct methodsusing SHELXS86 software package [8]. The isotropicrefinement of the structure was carried out by the least-squares method using SHELXL93 software package[9] followed by the anisotropic refinement of all thenon-hydrogen atoms. Among the 44 hydrogen atoms,29 atoms were located from the difference Fourier map,and their positions and isotropic thermal parameterswere refined. The coordinates of the remaining15 hydrogen atoms were determined geometrically.The final R-factor converged to R = 0.060. Atomic scat-tering factors were taken from the International Tablesfor X-ray Crystallography (1992, vol. C, Tables 4.2.6.8and 6.1.1.14). All the calculations were performed on aPentium computer. The crystallographic data are sum-marized in Table 1.

RESULTS AND DISCUSSION

The fractional coordinates and equivalent isotropicthermal parameters for non-hydrogen atoms are givenin Table 2. Endocyclic torsion angles are listed inTable 3. A general view of the molecule with atomicnumbering scheme is shown in Fig. 2 [10].

ClNO2

C8H17

Fig. 1. Chemical structure of 3β-chloro-6-nitrocholest-5-ene.

001 MAIK “Nauka/Interperiodica”

416

RAJNIKANT

et al

.

Table 1. Crystal data and other experimental details

Crystal habit Yellowish needlesChemical formula C27H44NO2ClMolecular weight 450.1Unit cell parameters, Å a = 7.207(1)

b = 11.292(1)c = 32.373(5)

Unit cell volume, Å3 2634.56Crystal system OrthorhombicSpace group P212121Density (calcd.), Mg m–3 1.135No. of molecules per unit cell (Z) 4Radiation CuKαWavelength (λ), Å 1.5418Absorption coefficient (µ), mm–1 1.44F(000) 984Crystal size, mm 0.30 × 0.20 × 0.15Refinement of unit cell: 25 reflections, 8.4° < θ < 17.3°θ range for entire data collection 2° < θ < 63°No. of measured reflections 2247No. of unique reflections 2231No. of observed reflections 1789 [Fo > 4σ(Fo)]No. of parameters refined 397Final R-factor 0.060wR 0.181

Weighting scheme 1/[σ2( ) + (0.1630P)2 + 2.86P], where P = [ + 2 ]/3Final residual electron density –0.21 < ∆ρ < 0.23 eÅ–3

(∆/σ)max in the final cycle 0.365 (for x H(25))Flack X parameter 0.04(6)

Fo2 Fo

2 Fc2

Table 2. Atomic coordinates and equivalent isotropic thermal parameters (Å2)

Atom x y z Atom x y z

Cl(1) 0.7411(4) 0.4673(2) 0.0737(1) 0.138(1) C(13) 1.5149(9) 0.4366(5) –0.1230(2) 0.077(2)C(1) 1.1679(9) 0.4149(4) –0.0076(2) 0.077(2) C(14) 1.4294(7) 0.4965(4) –0.1608(2) 0.064(1)C(2) 1.0243(11) 0.3895(5) 0.0266(2) 0.092(2) C(15) 1.3039(9) 0.4094(5) –0.1836(2) 0.077(2)C(3) 0.9104(11) 0.4969(5) 0.0341(2) 0.092(2) C(16) 1.3195(8) 0.6038(4) –0.1437(2) 0.071(1)C(4) 0.8104(11) 0.5360(6) –0.0055(2) 0.092(2) C(17) 1.2736(11) 0.6769(6) –0.1821(2) 0.087(2)C(5) 0.9440(8) 0.5566(4) –0.0399(2) 0.072(2) C(18) 1.4342(10) 0.6560(6) –0.2116(2) 0.083(2)C(6) 0.9484(9) 0.6535(4) –0.0615(2) 0.081(2) C(19) 1.5597(8) 0.5590(4) –0.1911(2) 0.070(2)N(1) 0.8249(10) 0.7502(4) –0.0513(2) 0.103(2) C(20) 1.6641(8) 0.4844(5) –0.2237(2) 0.075(2)O(1) 0.8620(11) 0.8160(5) –0.0245(3) 0.158(4) C(21) 1.7702(10) 0.3819(5) –0.2051(2) 0.099(2)O(2) 0.6891(13) 0.7646(7) –0.0703(2) 0.157(4) C(22) 1.7884(9) 0.5622(5) –0.2506(2) 0.094(2)C(7) 1.0716(12) 0.6836(5) –0.0979(2) 0.087(2) C(23) 1.8805(12) 0.5005(6) –0.2867(3) 0.113(3)C(8) 1.1634(8) 0.5720(4) –0.1142(2) 0.064(2) C(24) 2.0217(11) 0.5697(5) –0.3093(2) 0.100(2)C(9) 1.2395(8) 0.4994(4) –0.0777(2) 0.066(2) C(25) 2.1263(11) 0.5005(6) –0.3415(2) 0.097(2)C(10) 1.0837(7) 0.4559(3) –0.0488(2) 0.066(2) C(26) 2.2452(12) 0.4065(7) –0.3239(2) 0.131(3)C(11) 0.9728(12) 0.3531(5) –0.0685(3) 0.085(3) C(27) 2.2407(19) 0.5831(8) –0.3670(3) 0.163(4)C(12) 1.3726(9) 0.3999(5) –0.0912(2) 0.078(2)

* Ueq = (1/3) .

Ueq* Ueq

*

Uijai* a j

* ai a j⋅j

∑i∑

CRYSTALLOGRAPHY REPORTS Vol. 46 No. 3 2001

STRUCTURE ANALYSIS OF 3β-CHLORO-6-NITROCHOLEST-5-ENE 417

Cl(1)

C(3)

C(4)C(5)

C(2)C(1)

C(19)

C(10)

C(6)C(7)

N(1)

O(1)

O(2)

C(8)

C(9)

C(11)C(12)

C(18)

C(13)

C(17)

C(20)C(22)

C(16)

C(15)

C(14)

C(24)

C(23)C(21)

C(26)

C(25)

C(27)

DC

BA

Fig. 2. A general view of the molecule and atomic numbering scheme with thermal ellipsoids at a 50% probability.

The observed bond lengths and angles are in goodagreement with the corresponding values obtained inthe case of 5-ene steroidal molecules [11]. The meanvalue of the ë(sp3)–C(sp3) bonds [1.524(9) Å] agreeswith the value given in [12], even though the bondlengths C(2)–C(3) [1.484(9) Å], C(16)–C(17)[1.568(9) Å], C(23)–C(24) [1.477(10) Å], C(25)–C(26) [1.478(11) Å], and C(25)–C(27) [1.494(13) Å]show some significant deviations. The bond anglesC(12)–C(13)–C(17) [118.0(5)°], C(14)–C(13)–C(17)

CRYSTALLOGRAPHY REPORTS Vol. 46 No. 3 2001

[100.5(4)°], C(8)–C(14)–C(15) [118.6(5)°], andC(13)–C(17)–C(20) [119.0(5)°] exhibit significantdeviations from the ideal tetrahedral value (109.4°).These deviations are common to steroids as a result ofthe strain induced by ring junctions, side chains, andbond unsaturations. The bond length C(5)–C(6) isequal to 1.299(7) Å, which indicates a double-bondcharacter.

Ring A has a chair conformation with the asymme-try parameters ∆Cs[C(3)–C(10)] = 4.14 and ∆C2[C(2)–

Table 3. Endocyclic torsion angles (deg) (e.s.d.’s are given in parentheses)

C(2)–C(1)–C(10)–C(5) 49.1(6) C(14)–C(8)–C(9)–C(11) –45.7(6)

C(10)–C(1)–C(2)–C(3) –57.4(7) C(8)–C(9)–C(10)–C(5) –44.9(6)

C(1)–C(2)–C(3)–C(4) 58.6(7) C(8)–C(9)–C(11)–C(12) 45.1(7)

C(2)–C(3)–C(4)–C(5) –56.3(7) C(9)–C(11)–C(12)–C(13) –52.4(7)

C(3)–C(4)–C(5)–C(10) 51.0(7) C(11)–C(12)–C(13)–C(14) 57.2(6)

C(4)–C(5)–C(10)–C(1) –46.8(6) C(12)–C(13)–C(14)–C(8) –61.3(6)

C(6)–C(5)–C(10)–C(9) 12.1(7) C(14)–C(13)–C(17)–C(16) –39.8(5)

C(10)–C(5)–C(6)–C(7) 3.3(9) C(17)–C(13)–C(14)–C(15) 44.4(5)

C(5)–C(6)–C(7)–C(8) 14.4(9) C(13)–C(14)–C(15)–C(16) –31.4(6)

C(6)–C(7)–C(8)–C(9) –45.7(7) C(14)–C(15)–C(16)–C(17) 6.2(7)

C(7)–C(8)–C(9)–C(10) 63.6(6) C(15)–C(16)–C(17)–C(13) 21.5(6)

C(9)–C(8)–C(14)–C(13) 56.7(6)

418 RAJNIKANT et al.

C(3)] = 1.55 [13]. Ring B adopts a half-chair conforma-tion with the asymmetry parameter ∆C2[C(5)–C(6)] =1.7. Ring C has a chair conformation with its best rota-tional axis bisecting the C(9)–C(11) and C(13)–C(14)bonds and the asymmetry parameter ∆C2[C(9)–C(11)] = 4.75. The best mirror plane passes through theC(9) and C(13) atoms, with ∆Cs[C(9)–C(13)] = 3.44.Ring D is a distorted envelope with the phase pseudor-otation angle ∆ = 19.67° and the maximum torsionangle ϕ = 45.06° [14]. The asymmetry parameter∆Cs[C(13)] which gives a distortion from the ideal mir-ror symmetry bisecting the C(15)–C(16) bond, is equalto 7.72. The C(13) atom is disposed 0.665(5) Å abovethe plane defined by the other four ring atoms.

One bifurcated intramolecular hydrogen bond isobserved for C(4)–H(42)···N(1) [2.839(8) Å] and C(4)–H(42)···O(1) [3.242(9) Å]. There are two intermolecu-lar hydrogen bonds [(i) C(1)–H(11)···O(1a),H(11)···O(1), 2.63(4) Å; C(1)···O(1), 3.503(8) Å; CHO,151(4)°; (ii) C(3)–H(3)···O(2a), H(3)···O(2), 2.65(6) Å;C(3)···O(2), 3.558(11) Å; CHO, 175(5)°; symmetrycode: (a) 1/2 + x, 1/2 – y, –z] which contribute to the sta-bilization of the crystal structure.

ACKNOWLEDGMENTSRajnikant acknowledges the financial support

received from the University Grants Commission, Gov-ernment of India, under the DSA Research Program,project no. F/530/1/DSA/95(SAP-I).

REFERENCES1. V. K. Gupta, Rajnikant, K. N. Goswami, and K. K. Bhu-

tani, Cryst. Res. Technol. 29, 77 (1994).

C

2. V. K. Gupta, K. N. Goswami, K. K. Bhutani, andR. M. Vaid, Mol. Mater. 4, 303 (1994).

3. V. K. Gupta, Rajnikant, K. N. Goswami, et al., ActaCrystallogr., Sect. C: Cryst. Struct. Commun. C50, 798(1994).

4. A. Singh, V. K. Gupta, Rajnikant, and K. N. Goswami,Cryst. Res. Technol. 29, 837 (1994).

5. A. Singh, V. K. Gupta, Rajnikant, et al., Mol. Mater. 4,295 (1994).

6. A. Singh, V. K. Gupta, K. N. Goswami, et al., Mol.Mater. 6, 53 (1996).

7. J. Firoz, PhD Thesis (Aligarh Muslim Univ., Aligarh,1998).

8. G. M. Sheldrick, SHELXS86: Program for the Solutionof Crystal Structures (Univ. of Göttingen, Göttingen,1986).

9. G. M. Sheldrick, SHELXL93: Program for the Refine-ment of Crystal Structures (Univ. of Göttingen, Göttin-gen, 1993).

10. C. K. Johnson, ORTEP-II: A Fortran Thermal EllipsoidPlot Program for Crystal Structure Illustrations, ReportORNL-5138 (Oak Ridge National Laboratory, Tennes-see, 1976).

11. J. F. Griffin, W. L. Duax, and G. M. Weeks, Atlas of Ste-roid Structures (Plenum, New York, 1984), Vol. 2, p. 21.

12. Tables of Interatomic Distances and Configurations inMolecules and Ions, Ed. by L. E. Sutton (The ChemicalSociety, London, 1965), Chem. Soc. Spec. Publ. No. 18.

13. W. L. Duax, C. M. Weeks, and D. C. Rohrer, Topics inStereochemistry, Ed. by E. L. Eliel and N. Allinger(Wiley, New York, 1976), Vol. 9, p. 271.

14. C. Altona, H. J. Geise, and C. Romers, Tetrahedron 24,13 (1998).

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