Triethylamine → 1-{[4-(Aminomethyl)piperidin-1-yl)methyl]cyclobutanecarboxylic acid 4-methylbenzenesulfonate

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Reaction Steps

In a 500 mL, 3-necked round bottom flask under N2, a mixture of 1-[(4-{[(tert-butoxycarbonyl)amino]methyl}piperidin-1-yl)methyl]cyclobutane carboxylic acid (30 g, 92 mmol, Step 6) in THF (150 mL) was stirred at room temperature for 10 min. To this suspension, a solution of p-TsOH H2O (52.4 g, 276 mmol) in THF (150 mL) was added at room temperature. After stirring at that temp for 10 min, the resulting solution was heated under reflux condition for 3 hrs. After cooling down to room temperature, Et3N (28.1 mL, 202 mmol) was added very slowly during the period of 1 h with seeding. The white precipitate was formed during the addition of Et3N. The resulting white suspension was stirred at room temperature for 6 h and it was filtered and the obtained solid was washed with THF (100 mL×2), dried at 50° C. for 5 h to give 35 g (96%) of the titled compound as white powder

Provenance & Evidence