o-(1-Piperazinyl)phenol → Tert-butyl 4-(2-hydroxyphenyl)piperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence