Isopropyl chloroformate → HCID 10965615, compound

Temperature

0 °C

At about 0° C., isopropyl chloroformate (86.05 g, 702.16 mmol, 1.00 equiv.) was added dropwise, over a period of 60 minutes, to a stirred mixture of (S)-2-(tert-butoxycarbonylamino)propanoic acid (118 g, 623.65 mmol, 1.00 equiv.), tetrahydrofuran (500 mL), and triethylamine (63.63 g, 628.82 mmol, 1.00 equiv.). The resulting mixture was then stirred at about 0° C. for about 2 hours, and then the solids were removed by filtration. The resulting filtrate was then added to a hydroxylamine solution (formed by first stirring a mixture of sodium hydroxide (37.6 g, 940.00 mmol, 1.50 equiv.), methanol (500 mL), and hydroxylamine hydrochloride (65 g, 935.39 mmol, 1.50 equiv) at about 0° C. for about 2 hours, and then removing the resulting solids by filtration). The resulting mixture was stirred at about 0° C. for about 2 hours, the solids were removed by filtration, and the resulting filtrate was concentrated in vacuo. The resulting residue was purified by silica gel column chromatography (ethyl acetate/petroleum ether (1:1)) to give the title product as a white solid (70 g; yield=55%). 1H NMR (300 MHz, CDCl3) δ: 5.18 (b, 1H), 4.21 (m, 1H), 2.06 (s, 1H), 1.46 (s, 9H), 1.40 (d, J=7.2 Hz, 3H).

1. customthe solids were removed by filtration
2. additionThe resulting filtrate was then added to a hydroxylamine solution (
3. customformed
4. stirringby first stirring
5. customremoving the resulting solids
6. filtrationby filtration)
7. stirringThe resulting mixture was stirred at about 0° C. for about 2 hours
8. customthe solids were removed by filtration
9. concentrationthe resulting filtrate was concentrated in vacuo
10. customThe resulting residue was purified by silica gel column chromatography (ethyl acetate/petroleum ether (1:1))

ORD record

ord-a9ebdcecc7ac411f8f89f964ef57759d

Source dataset

uspto-grants-2014_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08802850B2