Trifluoroacetic acid → HCID 67764603, compound

Participants

Reaction Steps

N-tert-butyloxycarbonylpiperazine (1.0 g, 5.34 mmol) was dissolved in 5 mL of THF: water (1:1) and cooled in an ice bath. Triethylamine (1.45 mL, 10.68 mmol), followed by diethylchlorophosphate (1.16 mL, 8.01 mmol) in 5 mL of ether were added, and stirred at 0° C. for 1 hour and at room temperature for 2 hours. Solvents were removed and 40 mL of ethyl acetate was added to the residue. The ethyl acetate layer was washed with brine (30 mL×3) and dried over anhydrous sodium surf ate. After filtered, the filtrate was concentrated in vacuo to yield 1.5 g of N-tert-butyloxycarbonyl--N'-diethylphosphoryl-piperazine in 88% yield as an oil. MS m/z M+H=323, M+NH4 =340. H1 -NMR (in CDCl3) δ=1.32 (t, 6H, 2×CH3), 1.48 (s, 9H, Boc), 3.1 (m, 4H, piperazine), 3.37 (t, 4H, piperazine), 4.05 (m, 4H, 2×OCH2). The obtained N-tert-butyloxycarbonyl--N'-diethylphosphoryl-piperazine (1.5 g, 4.66 mmol) was dissolved in I 0 mL of 10% trifluoroacetic acid in methylene chloride and stirred at room temperature for 30 minutes. Solvent and trifluoroacetic acid were removed to obtain 1.6 g of N-diethylphosphorylpiperazine trifluoroacetic acid salt in quantitative yield. MS m/z M+H=223, H1 -NMR (in MeOH-d4) δ=1.35 (m, 6H, 2×CH3), 3.19 (m, 4H, piperazine), 3.37 (m, 4H, piperazine), 4.05 (m, 4H, 2×OCH2).

Provenance & Evidence