2-Chloroethyl chloroformate → HCID 58730268, compound

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Reaction Steps

2-chloroethyl chloroformate (429 mg, 3 mmol) was added slowly to a mixture of tert-butyl 1-piperazinecarboxylate obtained as step (ii) in Example 2 (559 mg, 3 mmol) and diisopropylethylamine (407 mg, 3.15 mmol) in CHCl3 (25 ml) at 0° C. The mixture was stirred for 2 h at room temperature. CHCl3 (50 ml) was then added and the solution was washed with 5% NaHCO3 (3×50 ml), brine (2×50 ml), and then dried over Na2SO4. The solution was filtered and evaporated to dryness. The residue was dissolved in CH2Cl2 (25 ml) at room temperature, and propargylamine (0.205 ml, 165 mg, 3 mmol) was added. After 24 h of stirring at room temperature, the solvent was removed by vacuum, and to the residue was added 20 ml of a solution of TFA:H2O:TES:thioanisole (85:5:5:5). The mixture was then stirred at room temperature for 2 h. The solution was evaporated to dryness in vacuum. The resulted residue was dissolved in water (10 ml) and then basified with Na2CO3 (pH 11), and extracted with Et2OAc (3×50 ml). The organic layer was washed with brine (2×50 ml) and dried over Na2SO4 overnight. Evaporation in vacuum gave the title compound H1: (251 mg, 40% total yield). H1 NMR (250 MHz, CDCl3+D2O) 2.26 (m, 1H), 3.11 (s 2H), 3.29 (dd, J=10.21, 7.45 Hz, 2H), 4.29 (d, J=11.23, 7.12 Hz, 2H), 2.55 (dd, J=4.73, 4.50 Hz, 4H), 2.93 (dd, J=4.96, 4.84 Hz, 4H). Mass spectrometry: calculated for C10H17N3O2 m/z [M+H]+=212.26, found [M+H]+=212.22.

Provenance & Evidence