Sodium Bicarbonate → (S)-5-((((2-azidobenzyl)oxy)carbonyl)amino)-2-((tert-butoxycarbonyl)amino)pentanoic acid

2-Azidobenzyl (4-nitrophenyl) carbonate (Compound tk13) (458 mg, 1.459 mmol) was added to a suspension of Boc-Orn-OH (Compound tk56) (308 mg, 1.326 mmol) and sodium bicarbonate (278 mg, 3.32 mmol) in 1,4-dioxane (3 mL)-water (2 mL). The reaction mixture was stirred at room temperature for 20.25 hours and then cooled in an ice bath and diluted with ethyl acetate and water, and a saturated aqueous potassium bisulfate solution (1.5 mL) was added to the resulting mixture. The mixture was extracted with ethyl acetate (×2), and the organic phase was washed with water (10 mL×2) and brine (10 mL) and dried over sodium sulfate. Following concentration under reduced pressure, the resulting crude product was purified by normal-phase silica gel column chromatography (hexane/ethyl acetate) to afford (S)-5-((((2-azidobenzyl)oxy)carbonyl)amino)-2-((tert-butoxycarbonyl)amino)pentanoic acid (Compound tk61) (556.0 mg, quant.).

1. temperaturecooled in an ice bath
2. extractionThe mixture was extracted with ethyl acetate (×2)
3. washthe organic phase was washed with water (10 mL×2) and brine (10 mL)
4. dry with materialdried over sodium sulfate
5. concentrationconcentration under reduced pressure
6. customthe resulting crude product was purified by normal-phase silica gel column chromatography (hexane/ethyl acetate)

ORD record

ord-ce0eba71f6f44238975779f83ceb4b43

Source dataset

uspto-grants-2016_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09409952B2