Water → N-t-butyloxycarbonyl-O-(3-nitro-2-pyridyl)-L-serine

Temperatur

0 °C

To a stirring solution of N-t-butyloxycarbonyl-L-serine (2.26 g) in N,N-dimethylformamide (15 mL) under argon at −20° C. was slowly added sodium hydride (60% oil dispersion, 0.88 g gross weight). The resulting mixture was warmed to 0° C. for 1 h, then recooled to −20° C. before a solution of 2-chloro-3-nitropyridine (1.6 g) in N,N-dimethylformamide (10 mL) was added over 10 min. The resulting red solution was stirred at −20° C. for 1 h. Water (100 mL) was then added, and the mixture was washed with diethyl ether (30 mL twice). The aqueous layer was adjusted to pH 7 with 1.0 M aqueous hydrochloric acid and extracted with ethyl acetate (30 mL three times). The combined extracts were washed with brine (50 mL), dried over anhydrous sodium sulfate, and evaporated under vacuum. The resulting residue was purified by silica gel chromatography eluting with ethyl acetate-hexane (1:2) to obtain N-t-butyloxycarbonyl-O-(3-nitro-2-pyridyl)-L-serine (2.46 g).

1. customat −20° C.
2. additionwas added over 10 min
3. washthe mixture was washed with diethyl ether (30 mL twice)
4. extractionextracted with ethyl acetate (30 mL three times)
5. washThe combined extracts were washed with brine (50 mL)
6. dry with materialdried over anhydrous sodium sulfate
7. customevaporated under vacuum
8. customThe resulting residue was purified by silica gel chromatography
9. washeluting with ethyl acetate-hexane (1:2)

ORD-Eintrag

ord-29042cdc7dcd480dae656ad35e772398

Quelldatensatz

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07425550B2