Cyclic uridine-3',5'-phosphate: molecular structure.

The crystal structure of the triethylammonium salt of cyclic uridine-3',5'-phosphate was solved by use of the tangent formula to refine phase angles based upon the positions of six of the atoms. The two independent uracil rings are planar and in the keto form. The base-sugar torsion angles are in the anti range. The sugar puckering is C3'-endo, and the ribose conformation about the C5'-C4' bond is transgauche.