electronic reprint - Department of Crystal and Structural Chemistry

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electronic reprint - Department of Crystal and Structural Chemistry

electronic reprintActa Crystallographica Section EStructure ReportsOnlineISSN 1600-5368(1E,3S,4aR,12aR)-3-Isopropenyl-8-methoxy-3,4,4a,5,6,11,12,12a-octahydro-1(2H)-chrysenoneoximeHuub Kooijman and Anthony L. SpekCopyright © International Union of CrystallographyAuthor(s) of this paper may load this reprint on their own web site provided that this cover page is retained. Republication of this article or itsstorage in electronic databases or the like is not permitted without prior permission in writing from the IUCr.Acta Cryst. (2003). E59, o121–o123 Kooijman and Spek ¯ C 23 H 29 NO 2


organic papersActa Crystallographica Section EStructure ReportsOnlineISSN 1600-5368(1E,3S,4aR,12aR)-3-Isopropenyl-8-methoxy-3,4,4a,5,6,11,12,12a-octahydro-1(2H)-chrysenone oximeHuub Kooijman* andAnthony L. SpekBijvoet Center for Biomolecular Research,Department of Crystal and Structural Chemistry,Utrecht University, Padualaan 8, 3584 CHUtrecht, The NetherlandsThe title compound, C 23 H 29 NO 2 , has two independent moleculesin the asymmetric unit, differing in the conformation ofthe propylene side chain. Hydrogen bonding of the oximemoiety joins the independent molecules into a dimer, withgraph-set R 2 2[6].Received 20 December 2002Accepted 23 December 2002Online 10 January 2003Correspondence e-mail:h.kooijman@chem.uu.nlKey indicatorsSingle-crystal X-ray studyT = 150 KMean (C±C) = 0.007 AÊR factor = 0.057wR factor = 0.156Data-to-parameter ratio = 8.1CommentThe crystal structure of the title compound, (I), was determinedto con®rm, beyond any doubt, the stereochemistryaround ring junction C4aÐC12a of this (unnatural) d-homosteroidskeleton (Drach et al., 2003). The con®guration ofatom C3 was known to be R. In both independent molecules(see below), the con®gurations of atoms C4a and C12a werefound to be S and R, respectively.For details of how these key indicators wereautomatically derived from the article, seehttp://journals.iucr.org/e.# 2003 International Union of CrystallographyPrinted in Great Britain ± all rights reservedThe title compound crystallizes with two independentmolecules in the asymmetric unit. An atomic displacementellipsoid plot is given in Fig. 1, together with the adoptedlabelling scheme for atoms and rings. The molecule labelledC1±C20 will be referred to as molecule 1. The labels of molecule2 are obtained by adding 50 to the numerical part of thelabel of the corresponding atom in molecule 1. The independentmolecules differ only slightly in conformation. Fig. 2shows a plot of the superposition of the two molecules usingthe quaternion transformation method (Mackay, 1984). Theindependent molecules are related by a 172 rotation alongthe vector [ 0.02, 1.00, 0.00], see Fig. 3. The most obviousdifference is the orientation of the isopropenyl moiety, as canbe expressed by the torsion angles C2ÐC3ÐC15ÐC17 andC52ÐC53ÐC65ÐC67, which are 22.7 (7) and 2.8 (7) ,respectively. There is also a small difference in the orientationof the oxime H atom, as is indicated by the torsion angles C1ÐN13ÐO14ÐH14 (160 ) and C51ÐN63ÐO64ÐH64 (140 ).The conformation of the steroid skeleton in bothindependent molecules is the same. Ring B adopts a screwboatconformation, with the local twofold rotation axisrunning through the midpoint of the bond C10AÐC10B[relevant asymmetry parameters (Duax & Norton, 1975) areActa Cryst. (2003). E59, o121±o123 DOI: 10.1107/S1600536802023693 Kooijman and Spek C 23 H 29 NO 2 o121electronic reprint


organic papersTable 1Selected geometric parameters (A Ê , ).O14ÐN13 1.419 (5)N13ÐC1 1.288 (6)O18ÐC8 1.373 (5)O18ÐC19 1.420 (7)C4BÐC10B 1.344 (6)O64ÐN63 1.428 (5)N63ÐC51 1.265 (6)O68ÐC58 1.372 (6)O68ÐC69 1.423 (7)C54BÐC60B 1.346 (6)O14ÐN13ÐC1 113.0 (4) O64ÐN63ÐC51 114.3 (4)Table 2Hydrogen-bonding geometry (A Ê , ).DÐHA DÐH HA DA DÐHAO14ÐH14N63 0.96 1.92 2.772 (5) 147O64ÐH64N13 0.84 2.06 2.773 (5) 142Due to the absence of signi®cant anomalous scatterers, the absolutecon®guration could not be determined ab initio. The chirality waschosen in agreement with the well known stereochemistry of atomC3. For 3152 of the 3787 unique re¯ections reported above, theintensities of the Friedel-related re¯ections were measured. Friedelopposites were merged before re®nement. H atoms bonded to Catoms were introduced in calculated positions, and were riding ontheir carrier atoms during re®nement. The oxime H atom could belocated in a difference Fourier map. To improve the data/parameterratio, the oxime H was not re®ned, but was included in the model inriding mode on the oxime O atom.Data collection: COLLECT (Nonius, 1998); cell re®nement:DENZO (Otwinowski & Minor, 1997); data reduction: DENZO;program(s) used to solve structure: SHELXS86 (Sheldrick, 1985);program(s) used to re®ne structure: SHELXL97 (Sheldrick, 1997);molecular graphics: PLATON (Spek, 2002); software used to preparematerial for publication: PLATON.We thank Professor Dr Aede de Groot and Ir Floor SarabeÁrof the Laboratory of Organic Chemistry, WageningenUniversity, for the provision of the crystals. This work wassupported in part (ALS) by the Council for the ChemicalSciences of the Netherlands Organization for Scienti®cResearch (CW-NWO).ReferencesBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem.Int. Ed. Engl. 34, 1555±1573.Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354±1358.Drach, F., Charnikhova, T., SarabeÁr, F. C. E., Jansen, B. J. M. & de Groot, Ae.(2003). J. Org. Chem. In preparation.Duax, W. L. & Norton, D. A. (1975). In Atlas of Steroid Structures. New York:Plenum.Mackay, A. L. (1984). Acta Cryst. A40, 165±166.Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands.Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276,Macromolecular Crystallography, Part A, edited by C. W. Carter Jr andR. M. Sweet, pp. 307±326. New York: Academic Press.Sheldrick, G. M. (1985). SHELXS86. University of GoÈ ttingen, Germany.Sheldrick, G. M. (1997). SHELXL97. University of GoÈ ttingen, Germany.Spek, A. L. (2002). PLATON. Utrecht University, The Netherlands. Internet:http://www.Cryst.Chem.uu.nl/PLATON/.Acta Cryst. (2003). E59, o121±o123 Kooijman and Spek C 23 H 29 NO 2 o123electronic reprint

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