2-({3-[(2R,4S,5R)-4-Hydr-oxy-5-hydroxy-methyl-2,3,4,5-tetra-hydro-furan-2-yl]-5-methyl-2,6-dioxo-1,2,3,6-tetra-hydro-pyrimidin-1-yl}meth-yl)isoindoline-1,3-dione.

The title compound, C(19)H(19)N(3)O(7), is a thymidine derivative and serves as an inter-mediate in the synthesis of a (99m)Tc radiolabeled nucleoside analog. Inter-molecular O-H⋯O hydrogen bonding is observed between the hydr-oxy functionalities of the ribose unit themselves as well as between a hydr-oxy group and an O atom of the phthalimide group of an adjacent mol-ecule. The mol-ecules are stacked on top of each other in the direction of the a axis. The crystal packing is further stabilized by weak intra- and inter-molecular C-H⋯O hydrogen bonds. The absolute configuration of the compound is known from the synthesis.