Tetrahydrofuran thf

Sodium hypochlorite (NaClO, 14%), sodium hydrogen phosphate (NaH₂PO₄), sodium chloride (NaCl), calcium chloride dihydrate (CaCl₂∙2H₂O), magnesium sulfate heptahydrate (MgSO₄∙7H₂O), sodium hydrogen carbonate (NaHCO₃), potassium nitrate (KNO₃), sodium nitrate (NaNO₃), calcium carbonate (CaCO₃), magnesium chloride hexahydrate (MgCl₂∙6H₂O), potassium sulfate (K₂SO₄), sodium sulfate (Na₂SO₄), calcium sulfate dihydrate (CaSO₄∙2H₂O), boric acid (H₃BO₃, 0.5%), hydrogen peroxide (H₂O₂, 30%), and chloride acid (HCl, 0.1 M) were purchased from Scharlab S.L., Barcelona, Spain. The ultrapure water (Milli-Q) used in the experiments was obtained from Millipore, Molsheim, France, equipment (conductivity less than 0.055 µS cm⁻¹).
Polyvinyl chloride (PVC, Mw 112,000 g mol⁻¹) was supplied by ATOCHEM, Madrid, Spain. Tetrahydrofuran (THF) was purchased from Scharlab S.L. Amberlite^® IRA-402 (Cl⁻ form, total exchange capacity ≥ 1.0 mol L⁻¹) was supplied by Merck Life Science, Darmstadt, Germany, S.L.U.

Heparin sodium (150 I.U./mg min) and 4-Nitrophenyl chloroformate (NPC) were supplied by Acros Organics (Geel, Belgium). Poloxamer 407 (Mw 12,600 g/mol), iron(II) chloride tetrahydrate (FeCl₂·4H₂O, 99%), iron(III) chloride hexahydrate (FeCl₃·6H₂O, 97%), oleic acid (OA, 99%), 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDC), and DOX (98–102%) were purchased from Sigma-Aldrich (St Louis, MO, USA). Tetrahydrofuran (THF) was obtained from Scharlau (Sentmenat, Spain). Diethyl ether was received from Fisher Scientific (Houston, TX, USA). All chemicals and solvents were of analytical grade and used without further purification.

All chemical reagents and solvents were obtained from Sigma-Aldrich (Munich, Germany), Scharlab (Barcelona, Spain) and Eurisotop (Saint-Aubin, France). Tetrahydrofuran (THF, ≥99.9% (GC), Scharlab, Barcelona, Spain) was dried using a drying agent (calcium hydride, CaH₂, 95%, Aldrich, Munich, Germany), degassed by three freeze-degas-thaw cycles and distillated under reduced pressure at 323 K. (±)-Epichlorohydrin (ECH, ≥99% (GC), Sigma Aldrich) was purified by distillation following the same procedure explained before for the purification of THF. The purification of tris(pentafluorophenyl)borane (B(C₆F₅)₃, 95%, Sigma Aldrich) was performed by sublimation under reduced pressure at 333 K using a cold finger condenser. Dichloromethane (CH₂Cl₂, anhydrous, Sigma Aldrich) was degassed by bubbling Argon for 30 min prior to use. (+)-Sodium l-ascorbate (BioXtra, ≥99% (NT), Sigma Aldrich), N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA, 99%, Sigma Aldrich), Propargyl ether (98%, Sigma Aldrich), N,N-dimethylformamide (DMF, anhydrous, ≥99.8%, Scharlab), sodium azide (NaN₃, ≥99.5%, Sigma Aldrich), and methanol (MeOH, ≥99.9%, Scharlab) were used as received. Copper (I) bromide (CuBr, 98%, extra pure, Acros Organics, Fair Lawn, NJ, USA) was purified following the Keller and Wycoff method [16 (link)].