Hydrochloric Acid → (5-Bromothiophen-2-yl)(2-((pyridin-3-yloxy)methyl)piperazin-1-yl)methanone dihydrochloride

4 M HCl in 1,4-dioxane (6 mL, 24 mmol) was added to a solution of tert-butyl 4-(5-bromothiophene-2-carbonyl)-3-((pyridin-3-yloxy)methyl)piperazine-1-carboxylate (192.6 mg, 0.399 mmol) in MeOH (1 mL). After 1 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 desired chromatography fractions were concentrated under reduced pressure, dissolved in MeOH (1 mL), and treated with 4 M HCl in 1,4-dioxane (6 mL). This was concentrated under reduced pressure, yielding 108 mg (59%) of the desired product as a white solid. LC-MS: RT=4.16 min, [M+H]+=382.0.