In the same way as that described in Example 2, Step 4, using Intermediate 2 (150 mg, 0.62 mmol), methanesulphonyl chloride (96 μL, 1.24 mmol), triethylamine (172 μL, 1.24 mmol) and THF (80 mL), followed by more triethylamine (86 μL, 0.62 mmol) and methanesulphonyl chloride (48 μL, 0.62 mmol). The resultant crude mesylate was then treated with 1-benzylpiperazine-2-thione (255 mg, 1.24 mmol), K2CO3 (257 mg, 1.9 mmol), sodium iodide (93 mg, 0.62 mmol) and iso-propanol (20 mL). The crude produce was chromatographed on silica gel, eluting with CH2Cl2 :MeOH:NH3 (95:5:1), to give the title compound (104 mg) as a pale yellow foam, contaminated with some 1-benzylpiperazin-2-thione. The mixture of thioamides (104 mg) was dissolved in CH2Cl2 (25 mL) and treated with di-tert-butyldicarbonate (50 mg, 0.23 mmol). The mixture was stirred at room temperature for 2 h then the solvent removed in vacuo. The residue was chromatographed on silica gel, eluting with CH2Cl2 :MeOH (95:5), to afford the title compound (47 mg, 18%) as a colourless solid, mp. (MeOH) 201-203° C. C24H26N6S. 0.3(H2O) requires: C, 66.12; H, 6.15; N, 19.28%. Found: C, 66.09; H, 5.92; N, 19.23%. 1H NMR (360 MHz, d6 -DMSO) δ1.81-1.92 (2H, m), 2.42 (2H, t, J=7.1 Hz), 2.70-2.76 (4H, m), 3.37-3.42 (2H, m), 3.61 (2H, s), 7.27-7.38 (7H, m), 7.47 (1H, d, J=8.6 Hz), 7.77 (1H, s), 9.01 (2H, s), 11.07 (1H, br s). MS (ES+) (431, M+1).
