Crystallographic evidence for intramolecular C−H...O interactions in principal nucleosides. Refinement of the crystal structure of thymidine
Tóm tắt
An analysis of crystallographic data for the major nucleosides has shown that their molecules (except for guanosine) exhibit specific intramolecular C−H...O interactions, which are weak hydrogen bonds. In purine nucleosides these interactions are rare and rather weak. For pyrimidine nucleosides, in addition to the previously known intramolecular interaction C6−H6...O5′, we have revealed the intramolecular interactions C1′−H1′...O2 and C6−H6...O1′. The three interactions make approximately equal contributions to the stabilization of the anti-conformation in pyrimidine nucleosides and make this conformation prevailing. To enhance the reliability of the results of studying the C−H...O interactions in thymidine, we performed an additional, more exact, X-ray diffraction analysis of the substance.
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