Dibutyltin dilaurate

Dichloromethane (CH₂Cl₂), chloroform (CHCl₃, 99.94%), tetrahydrofuran (THF) (C₄H₈O, 99.94%) and ammonium hydroxide (NH₄OH, 24.06%) were received from Lach-Ner s.r.o., Neratovice, Czech Republic. α-bromoisobutyryl bromide (C₄H₆Br₂O, >98.0%), 3-thiopheneethanol (C₆H₈OS, 98.0%) and N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA) (C₉H₂₃N₃, >99.0%) were recieved from Tokyo Chemical Industry, Tokyo, Japan. Nitromethane (CH₃NO₂, 98+%), copper(I) bromide (CuBr, 98%), dibutyltin dilaurate (DBTDL, [CH₃(CH₂)₃]₂Sn[O₂C(CH₂)₁₀CH₃], iron(III) chloride, anhydrous (FeCl₃, 98%) and ethyl isocyanate (C₃H₅NO, 98%) were received from Alfa Aesar, Haverhill, MA, USA. Triethylamine (C₆H₁₅N, 99%), 3,4-ethylenedioxythiophene (EDOT, 99.0%) silica gel (SiO₂) and 2-hydroxyethyl acrylate (C₅H₈O₃, 97%) were received from Acros Organics, Geel, Belgium. Magnesium sulfate (MgSO₄, 99.4%) was received from VWR Chemicals, Leuven, Belgium. Acetone (C₃H₆O, 98.0%) and ethanol (C₂H₅OH, 96.0%) were received from Gram-mol, Zagreb, Croatia. Methanol (CH₃OH, 99.9%) was received from Carlo Erba Reagents, Val-de-Reuil, France and diethyl eter (C₄H₁₀O) was received from Macron Fine Chemicals, Radnor, PA, USA. All the solvents were used as received.

l-Lysine ethyl ester diisocyanate (LDI) was purchased from Alfa Aesar Co. Dibutyltin dilaurate (DBTDL), triethylene glycol monomethyl ether (mOEG₃), p-toluenesulfonic acid monohydrate (TsOH) were purchased from Tokyo Chemical Industry. l-Tartaric acid and d-tartaric acid were purchased from Nacalai Tesque, Inc. Anhydrous tetrahydrofuran (THF) and anhydrous N,N-dimethylformamide (DMF) were purchased from Kanto Chemical Co., Inc. Diethyl ether and benzene were purchase from Wako Pure Chemical Industries. The chiral diol monomer, l-OEG₃TA and d-OEG₃TA, were synthesized following the literature procedure^{21 (link)} by condensation between tartaric acid and mOEG₃ using TsOH as an acid catalyst.

All reagents were commercially available materials and were used without further purification. Maleic anhydride (≥98%) and dibutyltin dilaurate (95%) were provided by Alfa Aesar (Haverhill, MA, USA). Furan (≥99%) was obtained from Fluka. Hydroquinone (≥99%), 2-hydroxypropyl acrylate (HPA) (mixture of the isomers, 95%), 2-hydroxyethyl methacrylate (HEMA) (97%), hexamethylene diisocyanate (for synthesis), polyethylene glycol PEG 1000 (for synthesis), and 2-hydroxypropyl methacrylate (HPMA) (mixture of hydroxypropyl and 2-hydroxypropyl methacrylates, ≥97%) were purchased from Sigma-Aldrich (Steinheim am Albuch, Germany). Furfuryl alcohol (98%) and isophorone diisocyanate (98%) were provided by Acros Organics (Geel, Belgium). 2-hydroxyethyl acrylate (HEA) was kindly donated by Cognis Performance Chemicals (Hythe, UK). Chempur (Piekary Śląskie, Poland) provided analytical-grade ethanolamine and triethanolamine. Diethyl ether (99.5%) and anhydrous ethanol p.a. (99.8%) were provided by Avantor Performance Materials Poland S.A. (POCH, Gliwice, Poland). Acetone, isopropanol, xylene, toluene, and dichloromethane of high purity were purchased from StanLab (Lublin, Poland).