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

Participants

Reaction Steps

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.).

Provenance & Evidence