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

Temperature

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 record

ord-0855fb1c75354af99d14871d375e7943

Source dataset

uspto-grants-2006_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07098235B2