Oxalic Acid → Oxalate

Participants

Reaction Steps

(4-{3-[Benzothiazol-2-yl-(1-methyl-piperidin-4-yloxy)-methyl]-phenylsulfanyl}-butyl)-carbamic acid tert-butyl ester (140 mg) is dissolved in dichloromethane (1 mL) and trifluoroacetic acid (0.4 mL) is added. The reaction mixture is stirred at room temperature for 1 hour. The mixture is evaporated to dryness. The residue is basified by adding a solution of saturated sodium carbonate to pH 10 and the aqueous phase is extracted with dichloromethane. The pooled organic extracts are dried over magnesium sulfate and concentrated under reduced pressure. The residue is purified by chromatography (gradient dichloromethane/methanol/ammonia from 100/0/0 to 90/10/1). The residue is added to oxalic acid (1 equivalent) in acetone (0.5 ml), and the precipitate is filtered and dry to give 4-{3-[benzothiazol-2-yl(1-methylpiperidin-4-yloxy)methyl]phenylsulfanyl}butylamine, oxalate melting at 108° C.

Provenance & Evidence