Water → Tert-butyl 4-(methylsulfonyl)piperazine-1-carboxylate

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Reaction Steps

Methanesulfonyl chloride (34.38 ml, 443 mmol, 1.1 equiv.) was added slowly to a solution of 1-(tert-butoxycarbonyl)piperazine 6 (BOC-piperazine, 75 g, 403 mmol, 1.0 equiv.) and triethylamine (67.4 ml, 483 mmol, 1.2 equiv.) in methylene chloride (750 ml) while maintaining the internal temperature below 20° C. The solution was stirred at ambient temperature for 24 hours. The solution was poured onto a mixture of ice and water (1.5 L). The phases were separated and the aq. phase was extracted with methylene chloride (800 ml×2). The organic phases were combined, dried over MgSO4, filtered and concentrated to give tert-butyl 4-(methylsulfonyl)piperazine-1-carboxylate 7 as an off-white solid (105 g). 1H NMR (400 MHz, CDCl3) δ 1.45 (s, 9H), 2.75 (s, 3H), 3.15 (m, 4H), 3.50 (m, 4H).

Provenance & Evidence