M. Crozet, M. Giorgi, T. Terme
Apr 1, 2005
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Zeitschrift für Kristallographie - New Crystal Structures
Abstract
Ci2Hi4N206S, monoclinic, P12i/cl (no. 14), a = 8.0170(1) A, b = 23.6730(4) A, c = 8.8300(1) A, β = 115.759(1)°, V= 1509.3 A, Z = 4, Rgt(F) = 0.048, wRretfF) = 0.134, T= 293 K. Source of material The synthesis of diethyl 2-(2-methyl-5-nitrothiazol-4-ylmethylene)malonate has been already reported [1]. diethyl malonate, thus confirming our suggestion about the presence of a strong conjugating effect all along the molecule. Interestingly, the packing modes of both structures differ significantly though the major difference of both compounds is only the position of the methyl on the heterocycle. Whereas the molecules in [2] interact through weak hydrogen bonds, in die title structure the presence of the methyl on carbon C3 favor the formation of a C-H—π interaction with the heterocycle of an adjacent molecule (symmetry code \-x,-y,2-z). The distance between the centroid of the nitrothiazole ring and H5A atom of the methyl is 2.94 A and the C5-H24C-centroid angle is 136.0°. Moreover the two oxygen atoms of the nitro group are involved in weak hydrogen bonds with the methyl of a symmetry-related molecule (symmetry code -1 +x,y-1 +z) and one ethyl of the malonate of a second symmetry-related molecule (symmetry code Ι-χ,Υι+y, 1 Yi-z). Thus the molecules of the title compound are organized in the crystal in layers parallel to the b,c plane. Table 1. Data collection and handling. Crystal: Wavelength: μ· Diffractometer, scan mode: 20max* NfhkiUyx·· Criterion for /at», N(hkl)gc. N(param)nfuxa: Programs: colorless prism, size 0.4 χ 0.5 χ 0.5 mm Mo Ka radiation (0.71073 A) 2.42 cm 1 Bruker-Nonius KappaCCD, φ 57.38° 11241,3560 /obs > 2 oflabs). 3236 190 SIR92 [3], SHELXL-97 [4] Table 2. Atomic coordinates and displacement parameters (in A). Experimental details Η atoms on the C5 atom were placed in geometrically idealized positions. During the refinement they were allowed to rotate freely about the C—C bond with C—Η distances restrained to 0.96 A and ί / ^ Η ) = 1.5 Ueq(C). Discussion The title structure is comparable with that of diethyl 2-(l-methyl5-nitro-ltf-imidazol-4-ylmethylene)malonate [2]. The main intramolecular structural features reported for the latter structure are also available for title structure, e.g. coplanarity of the nitro group, five-membered-ring, methylene and one ester arm of the * Correspondence author (e-mail: patrice.vanelle@pharmacie.univ-mrs.fr) Atom Site X y ζ Uiso H(5A) 4e 0.2160 -0.0011 0.3901 0.089 H(5B) 4e 0.1893 0.0646 0.3744 0.089 H(5C) 4e 0.1062 0.0295 0.4761 0.089 H(10) 4e 0.8169 -0.0019 1.0934 0.051 H(15A) 4e 0.2616 -0.1399 0.5966 0.092 H(15B) 4e 0.1324 -0.1320 0.6996 0.092 H(16A) 4e 0.4051 -0.2206 0.7368 0.170 H(16B) 4e 0.1902 -0.2300 0.6506 0.170 H(16C) 4e 0.2926 -0.2177 0.8441 0.170 H(20A) 4e 0.8631 -0.1857 1.3604 0.088 H(20B) 4e 1.0143 -0.2019 1.2776 0.088 H(21A) 4e 0.6738 -0.2567 1.1813 0.166 H(21B) 4e 0.8671 -0.2811 1.3050 0.166 H(21C) 4e 0.8246 -0.2689 1.1173 0.166