Hydrochloric Acid → HCID 20735186, compound

Participants

Reaction Steps

To an ice-cold solution of tert-butyl 4-(1-methyl-1H-imidazol-4-ylsulfonyl)piperazine-1-carboxylate (36, 6.0 g, 18.18 mmol) in 1,4-dioxane (30 mL) was slowly added concentrated HCl (30 mL) drop wise over 30 minutes. The reaction mixture was warmed to room temperature and stirred for 2 h. The reaction mixture was concentrated under vacuum, azeotroped with toluene (3×100 mL) and the resultant solids dissolved in H2O (100 mL). The aqueous mixture was washed with CH2Cl2 (2×100 mL) then carefully neutralized with solid K2CO3 (15 g). The aqueous mixture was then extracted with CH2Cl2 (4×100 mL) and combined organic extracts were washed with brine (1×50 mL), dried (Na2SO4), filtered and concentrated under reduced pressure to afford 1-(1-methyl-1H-imidazol-4-ylsulfonyl)piperazine (37) as off-white foam (3.8 g, 90%): 1H NMR (400 MHz, CDCl3) δ (dd, J=1.1 Hz, 16.8 Hz, 2H), 3.80-3.75 (m, 5H), 3.74-3.65 (m, 2H), 3.37-3.1 (m, 2H), 3.0-3.25 (m, 2H); MS (ESI+) m/z 231 (M+H).

Provenance & Evidence