A mixture of methyl 2-[4-[2-[4-(4-pyridyl)piperazin-1-yl]-acetyl]phenoxy]isobutyrate (50 mg), 48% w/v hydrobromic acid (0.74 ml), dioxane (1 ml) and water (3 ml) was heated at 95° C. for 4 hours. The solution was cooled, diluted with water and freeze-dried to give the title compound, 40 mg, as a pale yellow solid: m.p. 163°-167° C.; NMR (D2O) δ 8.40 (2H, d), 8.16 (2H, d), 7.40 (2H, d), 7.21 (2H, d), 5.21 (2H, s), 4.32 (4H, b), 3.89 (4H, bt), 1.86 (6H, s); m/e 384 (M+H)+ ; calculated for C21H25N3.2HBr.2H2O: C, 43.3; H, 5.3; N, 7.2. found: C, 43.6; H, 5.3; N, 7.3%.
