E. Elamparuthi, T. Linker, A. Kelling
2009
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Zeitschrift für Kristallographie - New Crystal Structures
Abstract
C29H33NO7, orthorhombic, P2\2i2\ (no. 19), a = 24.738(1) Â, b = 10.5120(8) Â, c = 10.3749(6) Â, V= 2697.9 Â, Z = 4, RgJF) = 0.042, wRreffF) = 0.105, 7"= 210 K. Source of material The title compound was synthesized by radical addition of nitromethane to tri-O-benzyl-D-galactal in the presence of cerium(IV) ammonium nitrate (CAN) [1]. The deprotonation of the CH-acidic precursor with potassium hydroxide prior to oxidation was important, which facilitated the radical generation remarkably. After isolation of the pure galacto isomer by column chromatography (cyclohexane/ethyl acetate 6:1), the product (50 mg) was mixed with ethyl acetate (2 ml) and hexane (1 ml), and toluene (2 ml) was added slowly at room temperature until a clear solution resulted. Colorless single crystals were obtained after slowly volatilizing the solvents at room temperature for four days. Experimental details All of the hydrogen atoms were located from the difference fourier map and included in the refinement with {/¡so(H) = 1.2 Ueq(C). Discussion C-branched carbohydrates are important analogs of the naturally occurring saccharides and possess promising aspects as enzyme inhibitors. The title compound opens an easy access to Cfunctionalized glycosylamines by reduction of the nitro group [1]. The absolute configuration results from the parent galacto configured starting material, but the relative configuration, especially at the anomeric position, had to be established. From the coupling constants in the *H NMR spectrum the ̂ -galacto configuration was proposed, but the crystal structure now proves this alignment unequivocally. Thus, all stereogenic centers have the R configuration. Furthermore, the conformation of the sugar ring in the solid state was quite interesting, adopting an almost ideal chair form, with all substituents, except the 4-position, in an equatorial orientation. The absolute values of torsion angles are in the range of 55.5(2)° 64.2(3)°. They are quite similar to those reported for the ancestor compound methyl ß-D-galactopyranoside with endocyclic torsion angles of 52.37° 65.75° [2]. Ilie average length for the C—C bonds of 1.525(3) Â is the same as in the reference compounds within the standard deviation (ßD-galactopyranoside [2] and /3-D-galactose both 1.523 Â [3]). The bond lengths at the anomeric centre are clearly different (endocyclic: CI—Ol 1.414(3) Â, exocyclic: Cl—02 1.391(3) À). The other both exocyclic C—O bond lengths are significantly longer (1.424(3) Â for C3—03, 1.425(3) Â for C4—04 Â). These different C—O bond lengths at the anomeric centre are typically for such pyranoside ring systems and were also reported in the literature (endocyclic: 1.436(4) Â [2], 1.422(4) Â [3]; exocyclic: 1.400(4) Â [2], 1.396(4) Â [3]. The C3/4—Oeq/ax bond lengths do not differ within the standard deviation: C3—03eq 1.424(3) Â, C4—04ax 1.425(3) Â. The dihedric angles between the galactose moiety and the phenyl rings are 43.48(3)° (C10C15), 70.19(8)° (C17-C22) and 73.1(1)° (C24-C29). The torsion angles are 168.6(2)° for the methoxy group (C2-C1-02-C7) and 73.33(3)° for the nitromethyl substituent (C1-C2-C8-N1), respectively. The torsion angles of the benzyl moieties are 88.7(3)° for Cl 1-C10-C9-03, -171.1(2)° for C18-C17-C1604 and -71.7(4)° for C25-C24-C23-05, respectively. Table 1. Data collection and handling. Crystal: Wavelength: μ· Difiractometer, scan mode: 20max: Nfhklhaasusai, N(hkl)amqac: Criterion for /ote, Nfhkl) N(param)ntiuKd'· Programs: colorless prism, size 0.1 χ 0.4 χ 0.9 mm Mo Ka radiation (0.71073 A) 0.89 cm" STOEIPDS Π, ω 49.9° 34572,4728 /obs > 2 a(Iobs), 3556 435 SHELXS-97 [4], SHELXL-97 [5] Correspondence author (e-mail: us@chem.uni-potsdam.de) 68 C 2 9 H 3 3 N O 7 Table 2. Atomic coordinates and displacement parameters (in À). Table 2. Continued. Atom Site χ y ζ Cls0 Atom Site χ y ζ U& H(l) 4a 0.215(1) 0.747(2) 0.957(3) 0.059 H(2) 4a 0.228(1) 0.872(2) 0.705(3) 0.056 H(3) 4a 0.273(1) 0.934(2) 0.959(3) 0.054 H(4) 4a 0.2174(9) 1.117(2) 0.960(2) 0.052 H(5) 4a 0.178(1) 0.939(2) 1.045(3) 0.056 H(6A) 4a 0.098(1) 1.047(3) 0.887(3) 0.062 H(6B) 4a 0.083(1) 0.977(3) 1.011(3) 0.062 H(7A) 4a 0.176(1) 0.555(3) 0.948(3) 0.084 H(7B) 4a 0.120(1) 0.617(3) 0.900(3) 0.084 H(7C) 4a 0.138(1) 0.507(3) 0.803(3) 0.089 H(8A) 4a 0.325(1) 0.817(2) 0.727(3) 0.062 H(8B) 4a 0.309(1) 0.720(3) 0.846(3) 0.062 H(9A) 4a 0.350(1) 1.054(3) 0.967(3) 0.072 H(9B) 4a 0.309(1) 1.178(3) 0.937(3) 0.072 H(ll) 4a 0.433(1) 1.036(3) 0.841(3) 0.089 H(12) 4a 0.498(2) 1.129(4) 0.717(4) 0.119 H(13) 4a 0.484(1) 1.327(3) 0.600(4) 0.109 H(14) 4a 0.408(1) 1.422(4) 0.649(4) 0.098 H(15) 4a 0.334(1) 1.322(3) 0.775(3) 0.075 H(16A) 4a 0.245(1) 1.209(3) 0.716(3) 0.079 H(16B) 4a 0.206(1) 1.267(3) 0.825(3) 0.079 H(18) 4a 0.220(1) 1.441(3) 0.640(3) 0.081 H(19) 4a 0.168(1) 1.542(4) 0.468(3) 0.101 H(20) 4a 0.081(1) 1.444(4) 0.400(4) 0.112 H(21) 4a 0.058(2) 1.242(4) 0.507(4) 0.126 H(22) 4a 0.109(1) 1.142(4) 0.649(3) 0.095 H(23A) 4a 0.084(1) 1.262(3) 1.155(3) 0.075 H(23B) 4a 0.054(1) 1.130(3) 1.147(3) 0.075 H(25) 4a 0.080(2) 1.397(4) 0.958(4) 0.127 H(26) 4a 0.022(3) 1.450(6) 0.810(7) 0.186 H(27) 4a -0.058(2) 1.375(4) 0.738(5) 0.139 H(28) 4a -0.080(2) 1.183(4) 0.844(4) 0.110 H(29) 4a -0.024(1) 1.121(3) 1.011(3) 0.081 Table 3. Atomic coordinates and displacement parameters (in Â). Atom Site X y ζ Un t/22 t/33 t/12 Un t/23 C(l) 4a 0.2004(1) 0.7744(2) 0.8670(3) 0.056(1) 0.034(1) 0.057(2) -0.003(1) 0.005(1) -0.001(1) C(2) 4a 0.24390(9) 0.8463(2) 0.7922(3) 0.053(1) 0.033(1) 0.055(1) 0.000(1) 0.003(1) 0.001(1) C(3) 4a 0.25910(9) 0.9613(2) 0.8755(2) 0.049(1) 0.034(1) 0.051(1) -0.001(1) 0.002(1) -0.003(1) C(4) 4a 0.20886(9) 1.0432(2) 0.8983(2) 0.052(1) 0.0334(9) 0.044(1) -0.0007(9) -0.004(1) -0.004(1) C(5) 4a 0.16505(9) 0.9616(2) 0.9604(3) 0.054(1) 0.038(1) 0.047(1) 0.001(1) 0.002(1) -0.003(1) C(6) 4a 0.1116(1) 1.0289(2) 0.9723(3) 0.050(1) 0.045(1) 0.059(2) -0.000(1) 0.004(1) -0.007(1) C(7) 4a 0.1522(2) 0.5814(2) 0.8688(4) 0.088(2) 0.041(1) 0.082(2) -0.015(1) 0.026(2) 0.001(1) C(8) 4a 0.2935(1) 0.7662(2) 0.7681(3) 0.059(1) 0.038(1) 0.059(2) 0.004(1) 0.003(1) -0.003(1) C(9) 4a 0.3330(1) 1.1056(3) 0.8974(3) 0.063(2) 0.055(1) 0.063(2) -0.016(1) 0.000(1) -0.011(1) C(10) 4a 0.37663(9) 1.1679(2) 0.8196(3) 0.047(1) 0.052(1) 0.062(2) -0.008(1) -0.006(1) -0.016(1) C(ll) 4a 0.4260(1) 1.1098(3) 0.7988(4) 0.059(2) 0.064(2) 0.099(3) -0.001(1) -0.004(2) -0.028(2) C(12) 4a 0.4653(1) 1.1702(5) 0.7241(4) 0.047(2) 0.123(3) 0.127(3) -0.013(2) 0.013(2) -0.069(3) C(13) 4a 0.4552(2) 1.2878(4) 0.6726(4) 0.086(2) 0.102(3) 0.086(2) -0.038(2) 0.018(2) -0.030(2) C(14) 4a 0.4074(2) 1.3439(4) 0.6929(3) 0.095(2) 0.082(2) 0.068(2) -0.033(2) 0.004(2) 0.001(2) C(15) 4a 0.3680(1) 1.2866(3) 0.7644(3) 0.060(2) 0.059(2) 0.068(2) -0.008(1) -0.003(1) -0.009(1) C(16) 4a 0.2055(1) 1.2178(2) 0.7511(3) 0.085(2) 0.041(1) 0.071(2) -0.015(1) -0.021(2) 0.012(1) C(17) 4a 0.1703(1) 1.2755(2) 0.6507(2) 0.071(2) 0.045(1) 0.048(1) 0.004(1) -0.005(1) -0.003(1) C(18) 4a 0.1853(1) 1.3919(2) 0.5993(3) 0.107(2) 0.042(1) 0.053(2) 0.009(1) -0.002(2) -0.003(1) C(19) 4a 0.1529(2) 1.4539(3) 0.5105(3) 0.138(3) 0.057(2) 0.058(2) 0.031(2) -0.001(2) 0.003(2) C(20) 4a 0.1064(2) 1.3997(4) 0.4698(4) 0.111(3) 0.093(2) 0.076(2) 0.046(2) -0.005(2) 0.015(2) C(21) 4a 0.0911(2) 1.2836(5) 0.5186(4) 0.077(2) 0.139(3) 0.098(3) 0.006(2) -0.025(2) 0.018(3) C(22) 4a 0.1229(1) 1.2207(3) 0.6094(3) 0.070(2) 0.083(2) 0.084(2) 0.001(2) -0.017(2) 0.016(2) C(23) 4a 0.0703(1) 1.1943(3) 1.0933(3) 0.063(2) 0.063(2) 0.062(2) 0.021(1) 0.003(1) -0.008(1) C(24) 4a 0.03398(9) 1.2449(2) 0.9904(3) 0.052(1) 0.042(1) 0.062(2) 0.004(1) 0.004(1) 0.002(1) C(25) 4a 0.0469(2) 1.3532(4) 0.9256(5) 0.089(2) 0.090(2) 0.137(3) -0.030(2) -0.020(2) 0.052(3) C(26) 4a 0.0110(3) 1.3992(5) 0.8330(7) 0.179(5) 0.119(4) 0.167(5) -0.014(4) -0.032(4) 0.098(4) C(27) 4a -0.0362(2) 1.3373(5) 0.8079(5) 0.108(3) 0.128(4) 0.112(3) 0.032(3) -0.040(3) 0.019(3) C(28) 4a -0.0487(2) 1.2350(4) 0.8728(4) 0.072(2) 0.106(3) 0.096(3) 0.007(2) -0.020(2) -0.014(2) C(29) 4a -0.0141(1) 1.1879(3) 0.9627(3) 0.066(2) 0.061(2) 0.074(2) -0.011(1) -0.003(2) -0.001(2) N(l) 4a 0.28530(9) 0.6660(2) 0.6680(2) 0.076(1) 0.042(1) 0.052(1) 0.001(1) 0.011(1) -0.0037(9) 0(1) 4a 0.15412(6) 0.8518(1) 0.8830(2) 0.0527(9) 0.0373(7) 0.060(1) -0.0023(7) 0.0071(8) -0.0069(8) 0(2) 4a 0.18514(7) 0.6682(1) 0.7958(2) 0.073(1) 0.0338(7) 0.066(1) -0.0131(7) 0.0155(9) -0.0064(7) 0(3) 4a 0.30103(6) 1.0293(1) 0.8116(2) 0.0483(8) 0.0404(7) 0.058(1) -0.0065(7) 0.0010(8) -0.0090(7) 0(4) 4a 0.18912(7) 1.0917(1) 0.7790(2) 0.0625(9) 0.0339(7) 0.0503(9) -0.0041(7) -0.0081(8) 0.0014(7) 0(5) 4a 0.11980(6) 1.1402(2) 1.0472(2) 0.0545(9) 0.0532(9) 0.070(1) 0.0123(8) -0.0089(9) -0.0216(9) 0(6) 4a 0.25927(8) 0.6887(2) 0.5712(2) 0.086(1) 0.0505(9) 0.052(1) -0.0017(8) 0.005(1) 0.0053(8) 0(7) 4a 0.3071(1) 0.5639(2) 0.6865(2) 0.132(2) 0.057(1) 0.106(2) 0.040(1) -0.025(2) -0.017(1)