4 aminobenzenesulfonamide

A 10 wt% dimethylformamide (DMF) dispersion of the PFSA polymer with equivalent weight of 1100 in the Li⁺ form (MF-4SC, Plastpolymer, Saint-Petersburg, Russia) and multiwall CNTs (Taunit S12, NanoTechCenter, Tambov, Russia) were used. Nitric acid (special purity, >70%), acetone (reagent grade, >99.75%), hydrochloric acid (special purity, 35–38%), and potassium chloride (reagent grade) were bought in Chimmed (Moscow, Russia). D-glucose (Ph Eur, hydrated form, Merck, Darmstadt, Germany), p-toluenesulfonic acid (97.5%, Acros Organics, Geel, Belgium), ethanol (95%, Ferein, Minsk, Belarus), and 3-aminopropyl)trimethoxysilane (97%, Alfa Aesar, Ward Hill, MA, USA) were used. N-[(4-aminophenyl)sulfonyl]acetamide (>99%) and 4-aminobenzenesulfonamide (>99%) were supported from Sigma-Aldrich (Saint-Louis, MO, USA). Sulfacyl sodium-SOLOpharm eye drops (Grotex, Saint-Petersburg, Russia) were analyzed. The deionized water with resistance 18.2 MΩ and pH 5.41 ± 0.05 was obtained using a Simplicity^® Water Purification System (MerckMillipore, Darmstadt, Germany).

Commercially available reagents were used without additional purification unless otherwise stated. 4,5-dichlorophthalic anhydride, 4-aminobenzenesulfonamide, and 4-(2-aminoethyl)benzenesulfonamide were purchased from Sigma-Aldrich (Sydney, Australia). ¹H-NMR (400 MHz) and ¹³C-NMR (101 MHz) spectroscopy was obtained using a Gemini 400-MR NMR spectrometer (Varian, Palo Alto, CA, USA), using DMSO-d₆ as NMR solvent. Low-resolution ESI-MS was measured on an amaZon SL (Bruker Daltonics, Bremen, Germany). High resolution ESI-MS was performed on an Apex Ultra Fourier Transform Ion Cyclotron Resonance 7 T Mass Spectrometer (Bruker Daltonics, Bremen, Germany). The mass spectra were obtained by direct infusion electrospray ionization and are reported as mass to charge ratio (m/z) and relative intensity (%). The estimated purity for the synthesised inhibitors is > 93%, with the final yield approximately 70%. HPLC was performed using a CBM-20A Shimadzu HPLC system (Kyoto, Japan), with an Ascentis C18 HPLC column (particle size: 10 μm, length: 25 cm, internal diameter: 4.6 mm) purchased from Sigma-Aldrich (Sydney, Australia). The inhibition assay data was modelled with a nonlinear regression fit of the log[inhibitor] vs. normalised response (using a variable slope) in GraphPad Prism v7.02 software [40 ], and the IC₅₀ is reported with 95% confidence intervals.