Gemcitabine hydro­chloride (2′-deoxy-2′,2′-di­fluoro­cytidine hydro­chloride), C₉H₁₂N₃F₂O₄⁺·Cl⁻, is a β-nucleoside that is of pharmaceutical interest as an antitumor agent. The N atom of the cytidine ring is protonated due to salt formation. The sugar residue adopts a C3′-endo and C4′-exo conformation. In the asymmetric unit, gemcitabine cations and chloride ions are linked by N—HCl hydrogen bonds. In the crystal structure, screw-related gemcitabine cations are linked by O—HO hydrogen bonds to form molecular columns along the c axis and adjacent columns are interlinked by N—HCl and O—HCl hydrogen bonds.

In the title compound, C₃₃H₂₆Cl₃N₃OS, the oxadiazole, piperidine and benzothia­pezine rings adopt envelope, chair and twist-boat conformations, respectively. In the crystal, the mol­ecular aggregation is characterized by chains of centrosymmetrically related pairs connected through ClCl inter­actions [3.533 (2) Å], extending parallel to (202).

The asymmetric unit of the title compound, C₃₀H₂₇F₂N₃O₂, contains two independent mol­ecules. The pyrrolidine five-membered ring assumes an envelope conformation (with the CH₂ atom at the flap) in one mol­ecule and a twisted conformation in the other one. In both independent mol­ecules, the 4-piperidinone rings adopt a similar twisted chair conformation. In the crystal, the two independent mol­ecules form an R₂²(8) dimer through a pair of N—HO hydrogen bonds; the R₂²(8) dimers are connected via weak C—HO hydrogen bonds, leading to a chain extending along the c axis.