Methyl chloroformate → (R)-tert-butyl 3-((R)-(5-chloro-2-methylphenyl)(2-(methoxycarbonylamino)ethoxy)methyl)piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of (R)-tert-butyl 3-((R)-(2-aminoethoxy)(5-chloro-2-methylphenyl)methyl)piperidine-1-carboxylate (6.2 g, 16.2 mmol) and DMAP (0.2 g, 1.62 mmol) in dry CH2Cl2 (70 mL), Et3N (8 g, 81 mmol) was added. The resulting mixture was cooled to 0-5° C. in ice-water bath, a solution of methyl chloroformate (3.1 g, 32.4 mmol) in dry CH2Cl2 (30 mL) was added dropwise. After addition, the reaction mixture was stirred for 1-2 hr at 0-5° C. The reaction was quenched with water. The aqueous layer was extracted with CH2Cl2 (3×30 mL), the combined organic layers were washed with brine, then dried over Na2SO4, filtered and concentrated to give the crude product, which was firstly purified by column chromatography and then by preparative HPLC to give (R)-tert-butyl 3-((R)-(5-chloro-2-methylphenyl)(2-(methoxycarbonylamino)ethoxy)methyl)piperidine-1-carboxylate (1.5 g). 1H NMR (CD3OD, 400 MHz) δ 7.30 (s, 1H), 7.20-7.10 (d, 2H), 4.81 (s, 1H), 4.46-4.30 (d, 1H), 4.29-4.15 (d, 1H), 3.95-3.83 (d, 1H), 3.62 (s, 3H), 3.30 (s, 4H), 2.90-2.65 (dd, 2H), 2.30 (s, 3H), 1.70 (s, 1H), 1.59 (s, 1H), 1.41 (s, 9H), 1.35-1.20 (m, 3H).

Provenance & Evidence