o-(1-Piperazinyl)phenol → Tert-butyl 4-(2-hydroxyphenyl)piperazine-1-carboxylate
Reaction equation
[OH:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[N:8]1[CH2:13][CH2:12][NH:11][CH2:10][CH2:9]1.[C:14]([O:18][C:19](=O)[O:20]C(C)(C)C)([CH3:17])([CH3:16])[CH3:15]>O1CCCC1>[OH:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[N:8]1[CH2:13][CH2:12][N:11]([C:19]([O:18][C:14]([CH3:17])([CH3:16])[CH3:15])=[O:20])[CH2:10][CH2:9]1Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 60 °C
Procedure
To a stirred suspension of 1-(2-hydroxyphenyl)piperazine 19 (1.78 g, 0.01 mol) in 20 mL tetrahydrofuran (in a round bottom flask fitted with a gas bubbler) was added a solution of di-tert-butylcarbonate (2.62 g, 0.012 mol) in 10 mL tetrahydrofuran at room temperature. Soon it became a clear solution and a gas was evolved. The resulting mixture was heated at 60° C. for 6 h. The progress of the reaction was monitored by thin layer chromatography (TLC). The solvent was evaporated, the residue was dissolved in 100 mL ethyl acetate and washed with 100 mL water, dried over sodium sulphate (Na2SO4) and evaporated to give tert-Butyl 4-(2-hydroxyphenyl)piperazine-1-carboxylate 20 which was purified by triturating with hexanes. White solid, 2.5 g (92%). 1H NMR (400 MHz, CDCl3): δ 1.49 (s, 9H); 2.81(t, J=4.8 Hz, 4H); 3.58 (t, J=4.8 Hz, 4H); 6.84-6.88 (m, 1H); 6.94-6.99 (m, 1H); 7.06-7.12 (m, 2H).
Workup
- customfitted with a gas bubbler)
- customThe solvent was evaporated
- dissolutionthe residue was dissolved in 100 mL ethyl acetate
- washwashed with 100 mL water
- dry with materialdried over sodium sulphate (Na2SO4)
- customevaporated
Sources & evidence
- ORD record
- ord-88bd87917f334f35ab291224959aa25c
- Source dataset
- uspto-grants-2012_06
- Patent number
- US08207163B2
Reaction notes
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