[4-[5-[3-amino-6-[4-(dimethylcarbamoyl)phenyl]pyrazin-2-yl]-1,3,4-oxadiazol-2-yl]phenyl]methyl acetate (118 mg, 0.2445 mmol) was suspended in methanol (2 mL) and treated with NaOH (489.0 μL of 1 M, 0.4890 mmol). The resulting mixture was stirred at 55° C. for 1 h. The reaction mixture was cooled to room temperature and then neutralised with HCl (978.0 μL of 1 M, 0.9780 mmol), filtered and washed with acetonitrile. The resulting yellow powder was heated in acetonitrile (5 mL), cooled and filtered to give a pale yellow powder. This was purified by column chromatography on silica gel eluting with 5% MeOH/CH2Cl2 to give the product as a pale yellow powder (73 mg, 70%); 1H NMR (400 MHz, DMSO) d 2.98-3.02 (m, 6H), 4.64 (d, 2H), 5.44 (t, 1H), 7.54-7.62 (dd, 4H), 7.78 (br s, 2H), 8.12-8.18 (dd, 4H) and 8.98 (s, 1H) ppm; MS (ES+) 417.23
