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

Temperature

2.5 °C

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).

1. additionAfter addition
2. customThe reaction was quenched with water
3. extractionThe aqueous layer was extracted with CH2Cl2 (3×30 mL)
4. washthe combined organic layers were washed with brine
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated
8. customto give the crude product, which
9. customwas firstly purified by column chromatography

ORD record

ord-5ab96aa12c314666b762c0dc80142615

Source dataset

uspto-grants-2012_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08198453B2