Hydrochloric Acid → 6-Methyl-2-(2-((pyridin-3-yloxy)methyl)piperazin-1-yl)benzo[d]oxazole hydrochloride

4 M HCl in 1,4-dioxane (6 mL, 24 mmol) was added to a solution of tert-butyl 4-(6-methylbenzo[d]oxazol-2-yl)-3-((pyridin-3-yloxy)methyl)piperazine-1-carboxylate di-TFA salt (91.1 mg, 0.140 mmol) in MeOH (1 mL). After 2 h, the reaction mixture was concentrated under reduced pressure and purified by HPLC (5 to 50% MeCN/0.1% TFA in H2O/0.1% TFA gradient). The fractions containing the desired product were brought to pH 12 with 1 N NaOH, and brine (20 mL) was added. This was extracted with EtOAc (3 x). The combined organics were dried over Na2SO4, filtered, and concentrated under reduced pressure, yielding 33.0 mg of the free-base of the desired product. The material was dissolved in MeOH (1 mL) and 4 M HCl in 1,4-dioxane (0.025 mL) was added. The mixture was concentrated under reduced pressure to give 35.5 mg (70%) of the desired product as the hydrochloride salt. LC-MS: RT=4.40 min, [M+H]+=325.1.