The crystal and molecular structure of inosine

Abstract

The structure of inosine (C10N4OsH12) which crystallizes in the space group P21 with one molecule per asymmetric unit and with unit-cell dimensions: a=4.818+0.005, b= 10-45+0.01, c= 10.97+0.01/l, and ,8= 90043 ' + 2", has been determined from X-ray intensity data collected from linear and four-circle diffractometers. The structure was solved by a Patterson function interpretation method and the positional and thermal parameters were refined by the method of least squares, using anisotropic thermal parameters for the non-hydrogen atoms. The final R value for the 1298 observed reflexions was 0.046 and the standard deviations in the bond lengths and angles are about 0.004 ~ and 0-3 ° respectively. The purine ring in inosine is planar, but both O(10) and C(I') are significantly displaced from this plane. The dihedral angle between the base and sugar planes is 71.0 ° and the glycosidic torsion angle, ~0CN is

Dependence of 13C NMR Chemical Shifts on Conformations of RNA Nucleosides and Nucleotides

“…This is designated polymorph B. Finally, dehydration of commercial inosine or inosine dihydrate in an oven at 100°C for 24 h gives anhydrous monoclinic inosine (polymorph C), which has a single distinct molecule in the unit cell (32). The identity of all three polymorphs was confirmed by X-ray powder diffraction.…”

Structure of hypoxanthine

“…As expected, the C(5)-N(7)-C(8) bonding angle, for example, is increased by about 3-4 ° upon protonation at N(7). On the other hand, the N (7) (6) 127.4 (2) 127.9 (2) C(2)-N(1)-H (1) 116 (2) 119 ( (2) 118 (1) 126 (I) N(7)--C(8) --H(8) 121 (1) 126 ( (8) 126 (1) 121 (l) C0)--N(9)--H (9) 117 (2) 123 (2) C(8)--N(9)--H (9) 136 (2) 130 (2) average bond lengths and angles of the two independent molecules in hypoxanthine are not definitely different from those observed in the nucleoside inosine (representing a 9-substituted hypoxanthine) or in inosine dihydrate (Munns & Tollin, 1970;Thewalt, Bugg & Marsh, 1970). The purine ring is approximately planar in both molecules of hypoxanthine with maximum deviations of 0.013 ]k for N(1) in molecule A and of 0.016 A for N(I) and C (6) The molecular packing in the unit cell is shown in Fig.…”

The molecular and crystal structure of 5,6-dihydro-2-thiouridine, C9H14N2O5S

“…The variation of the energy with rotation about C(4')-C(5') indicates that for C(Y)-endo and C(2')-endo sugars the gauche-gauche, gauche-trans, and transgauche orientations are equally favourable and all three have been observed in nucleosides, although the gauche-gauche is the most common (Wilson & Rahman, 1971). In the structure of inosine I (Munns & Tollin, 1970) containing C(Y)-endo pucker, a gauchetrans conformation with ~0oc= 169 ° was observed.…”