A. Ramazani, A. Morsali, Ν. Noshiranzadeh
2002
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Zeitschrift für Kristallographie - New Crystal Structures
Abstract
C13H1 iBiOs, triclinio, PI (No. 2), a = 6.2993(7) Â, b = 9.737(1) Â, c = 11.142(1) Â, a = 104.313(3)°, β = 103.523(3)°, γ = 92.473(3)°, V = 640.1 Â, Z= 2, Rg[(F) = 0.036, wR^F) = 0.102, Γ =293 Κ. Source of material Dimethyl 6-bromo-2//-1 -benzopyran-2,3-dicarboxylate was synthesized in accordance with our new procedure [1]. The solution of title compound (0.4 g) in methanol (30 ml) left in room * Correspondence author (e-mail: a-ramazani@mail.znu.ac.ir) temperature for ten days. The colourless crystals were filtered off, washed with cold methanol (6 ml) and dried in vacuum over P4O10 (mp 412 K; yield 85%). Elemental analyses were consistent with the composition CnHnBrOs (found: C, 48.25%; H, 3.21%; calc. : C, 48.13%; H, 3.39%). Melting points were measured on an Electrothermal 9100 apparatus and are uncorrected. Elemental analyses were performed using a Heraeus CHN-O-Rapid analyser. Discussion 2ΗΛ -Benzopyran derivatives are important intermediates in the synthesis of many natural products and medicinal agents including some potassium-channel activating drugs [1-7], A feature common to all these compound is the presence of a strongly electron-withdrawing substituent at 6-position of the 2//-1-benzopyran ring [1], In the recent years, there has been increasing interest in the determination of X-ray crystal structures of biologically active compounds [7-9], In the structure of title molecule (upper figure), the covalent bonds are found to be normal (relevant bond lengths : ¿(Bri—C6) = 1.899(2) Â,d(01—C9)= 1.379(2) Â,d(01—Cl) = 1.430(2) Â, <¿(02—CIO) = 1.198(2) Â, d(03—C10) = 1.330(3) Â, d(03—C12) =1.451(3) Â, d (04—Ci l ) = 1.203(2) Â, d(05—Cl 1) = 1.343(3) Â, d(05—C13) =1.444(3) Â, d(Cl—Cl) = 1.516(3) Â, d(C 1 —C10)= 1.530(3) Â,d(C2—C3) = 1.332(3)Â, d(C2—Cl 1) = 1.475(3) Â, d(C3—C4) = 1.453(3) Â; angles at the O atoms : 114.40(14)° at Ol, 115.62(17)° at 03 and 115.67(17)° at 05) and are almost the same as in the previous reports [7-9]. The methyl groups at 03 and 05 are approximately in the planes 03-C10-02 (¿C12-03-C10-02 = 0.3(3)°) and 05-C11-04 (¿C13-05-C11-04 = -0.3(3)°), respectively, that agrees well with a participation of 03 and 05 in the electron donation to the carbonyl groups. The torsion angle ¿C3-C2-C11-04 = -172.7(2)°, shows clearly that the carbonyl group (Cll to 04) and C=C double bond (C3=C2) share approximately a common plane with S-trans conformation, probably is as a result of π-systems conjugations. Intermolecular ring stacking is observed in the structure, probably it is a result of the presence of parallel aromatic benzene rings in the crystal network (lower figure). Intermolecular electrostatic attractive interactions between Bri and 02 atoms (d(Brl —02) = 3.249(2) Â) are also observed in the crystal structure. This is probably a result of the presence of electron-poor (02) and electron-rich (S2) atoms in suitable positions of the crystal network. These intermolecular interactions appear to be plausible factors in the stabilization of the crystal packing. 596 C n H i i B i O s Table 2. Atomic coordinates and displacement parameters (in À). Atom Site χ ν ; Ι/, so Table 1. Data collection and handling. H(1A) 2 / -0.0339 1.5966 0.3962 0.040 H(3A) li 0.5022 1.4462 0.3079 0.042 Crystal: colourless plate, size 0.1 χ 0.4 χ 0.4 mm H(5A) 21 0.4523 1.1797 0.1804 0.046 Wavelength: Mo Ka radiation (0.71073 Â) H(7A) 21 -0.0438 0.9283 0.2113 0.055 μ· 32.24 cm" 1 H(8A) li -0.1836 1.1269 0.3170 0.049 Diffractometer, scan mode: Broker SMART 1000 CCD, φΐω H(12A) 21 -0.1527 1.7027 0.0124 0.091 Ιθπαχ'· 60° H(12B) 2/ -0.3633 1.6407 0.0414 0.091 WlW.)measured, N(hkl)miquc: 5527, 3666 H(12C) 2/ -0.2145 1.5373 -0.0238 0.091 Criterion for lobs, N(hkl)p: W > 2 a(/obJ, 2648 H(13A) 2ί 0.8090 1.8515 0.4078 0.085 /VCparam Wined: 174 H(13B) 2/ 0.6728 1.8907 0.5103 0.085 Programs: SHELXTL-97 [10), SADABS [11] H(13C) li 0.5815 1.9107 0.3729 0.085 Table 3. Atomic coordinates and displacement parameters (in Â). Atom Site X y ζ Un U22 t/33 U12 Un U2i Β κ η 2i 0.31293(4) 0.87488(2) 0.08663(3) 0.0766(2) 0.0384(1) 0.0731(2) 0.0160(1) 0.0316(1) 0.0050(1) 0(1) 2/ -0.0416(2) 1.3886(1) 0.3678(1) 0.0447(7) 0.0340(7) 0.0387(7) 0.0061(6) 0.0208(6) 0.0116(5) 0(2) 2 i -0.2778(2) 1.4142(2) 0.1409(2) 0.0431(8) 0.0434(8) 0.0497(9) -0.0029(6) 0.0019(7) 0.0094(7) 0(3) 2i -0.0861(2) 1.6216(2) 0.1626(2) 0.0478(8) 0.0497(9) 0.0455(9) -0.0062(7) -0.0007(6) 0.0223(7) 0(4) 2i 0.2551(3) 1.7935(2) 0.4332(2) 0.0553(9) 0.0349(8) 0.072(1) 0.0020(7) 0.0237(8) 0.0009(7) 0(5) 2/ 0.5553(2) 1.7089(2) 0.3785(2) 0.0388(8) 0.0334(7) 0.070(1) -0.0007(6) 0.0131(7) 0.0097(7) C(l) li 0.0065(3) 1.5175(2) 0.3352(2) 0.0373(9) 0.0297(8) 0.0349(9) 0.0050(7) 0.0146(7) 0.0078(7) C(2) 2i 0.2491(3) 1.5455(2) 0.3441(2) 0.0359(9) 0.0329(9) 0.0314(9) 0.0027(7) 0.0082(7) 0.0085(7) C(3) li 0.3553(3) 1.4333(2) 0.3084(2) 0.0310(9) 0.0354(9) 0.040(1) 0.0021(7) 0.0106(7) 0.0107(8) C(4) li 0.2409(3) 1.2904(2) 0.2702(2) 0.0341(9) 0.0313(9) 0.038(1) 0.0058(7) 0.0111(7) 0.0119(7) C(5) li 0.3236(3) 1.1700(2) 0.2062(2) 0.037(1) 0.0363(9) 0.045(1) 0.0092(8) 0.0139(8) 0.0117(8) C(6) 2i 0.2116(4) 1.0373(2) 0.1819(2) 0.049(1) 0.0331(9) 0.044(1) 0.0103(8) 0.0135(9) 0.0088(8) C(7) li 0.0248(4) 1.0193(2) 0.2247(2) 0.051(1) 0.032(1) 0.054(1) 0.0000(9) 0.013(1) 0.0113(9) C(8) li -0.0590(3) 1.1377(2) 0.2875(2) 0.042(1) 0.039(1) 0.047(1) 0.0004(8) 0.0164(9) 0.0134(9) C(9) 2 i 0.0450(3) 1.2721(2) 0.3059(2) 0.0368(9) 0.0336(9) 0.0320(9) 0.0050(7) 0.0104(7) 0.0105(7) C(10) 2 i -0.1370(3) 1.5088(2) 0.2016(2) 0.0306(9) 0.0347(9) 0.039(1) 0.0075(7) 0.0137(7) 0.0080(8) C( l l ) 2 i 0.3484(3) 1.6950(2) 0.3901(2) 0.038(1) 0.0351(9) 0.037(1) 0.0022(8) 0.0072(8) 0.0100(8) C(12) 2 i -0.2150(4) 1.6259(3) 0.0376(3) 0.060(2) 0.069(2) 0.052(2) 0.000(1) -0.005(1) 0.029(1) C(13) 2 i 0.6637(4) 1.8525(2) 0.4209(3) 0.046(1) 0.039(1) 0.078(2) -0.0080(9) 0.006(1) 0.015(1) Acknowledgment. Support of this investigation by Zanjan University Research Council (ZURC4950) is gratefully acknowledged.