0.2 mm precoated silica gel aluminium sheets 60 f 254

The uncorrected melting points were determined using a Reichert Kofler hot-stage apparatus. ¹H NMR and ¹³C NMR spectra were recorded on a Bruker AVANCE 400 (¹H, 400 MHz, ¹³C, 100 MHz) in DMSO-d₆, MeOD or CDCl₃. Chemical shifts are expressed in δ (ppm) and coupling constants (J) in Hertz. Magnesium sulphate was used as the drying agent. Evaporations were made in vacuo (rotating evaporator). Analytical TLCs have been carried out on Merck 0.2 mm precoated silica gel aluminium sheets (60 F-254). Silica gel 60 (230–400 mesh) was used for column chromatography. Purity of the target compounds 1–9 was determined using a Shimadzu LC-20AD SP liquid chromatograph equipped with a DDA Detector (λ = 254 nm) using a column C18 (250 mm × 4.6 mm, 5 µm, Shim-pack); the mobile phase, delivered at isocratic flow, consisted of 70% of acetonitrile and 30% H₂O (0.1% NH₃); flow rate 1 ml/min. All the compounds showed percent purity ≥ 95%. Reagents, starting materials, and solvents were purchased from commercial suppliers and used as received. The intermediate N-benzyl-5-methoxy-1H-indole 10 was prepared according to the reported procedure³⁷ (link).

Melting points were determined using a Reichert Köfler hot-stage apparatus and are uncorrected. Routine ¹H-NMR and ¹³C spectra were recorded in DMSO-d₆ on a Bruker 400 spectrometer operating at 400 MHz. Evaporation was performed in vacuo (rotary evaporator). Analytical TLC analyses were carried out on Merck 0.2 mm precoated silica gel aluminium sheets (60 F-254). Purity of the target inhibitors, 6a–g, was determined by HPLC analysis, using a Merck Hitachi D-7000 liquid chromatograph (UV detection at 242 nm) and a Discovery C18 column (250 mm × 4.6 mm, 5 μm, Supelco), with a gradient of 40% water and 60% methanol and a flow rate of 1.4 mL/min. All the compounds showed percent purity values ≥95%. 4-Aminobenzenethiol, 3-aminobenzenethiol, benzonitrile, 4-chlorobenzonitrile, 4-bromobenzonitrile and all the suitably substituted phenylisocyanates, used to obtain the target inhibitors, were from Sigma-Aldrich and Fluka.