Zeitschrift für Naturforschung / C / 36 (1981)
نویسندگان
چکیده
4-Thiouridine, Crystal Packing Forces, Molecular Structures 4-thiouridine crystallizes from butyric acid in the form of yellow needles, monoclinic space group P2 j with a = 10.136 (3), b = 4.843 (2 ), c = 11.257 (3) A, ß = 93.91 (5) °. The crystal structure was solved on the the basis of 895 X-ray counter data using direct methods and refined to a reliability index of R = 5.6%. 4-thiouridine is in the anti conformation, the torsion angle 0(1')-C(1')-N(1)-C(6) being 26.5°. Pseudorotation parameters Tmax = 41.1° and P = 15.7° refer to C(3')-endo (3E) envelope form of the ribose. The conformation about the C(5')-0(5') bond is gauche, gauche. The present structure is compared with the previous one, crystallized from water as sesquihydrate and existing as the syn conformer (W. Saenger and K. H. Scheit, J. Mol. Biol. 50, 153-169 (1970). The influence of crystal packing forces on flexible molecules such as nucleosides is discussed.
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Zeitschrift für Naturforschung / C / 38 (1983)
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