Boc-Orn(Boc)-OH, is an amino acid building block used in peptide synthesis. With a growing peptide drug market the fast, reliable synthesis of peptides is of great importance.
The general procedure for the synthesis of (2S)-2,5-bis[(tert-butoxycarbonyl)amino]pentanoic acid from di-tert-butyl dicarbonate and L-ornithine hydrochloride was as follows: (S)-2,5-diaminopentanoic acid hydrochloride (1a) (337 mg, 2 mmol), di-tert-butyl dicarbonate ((Boc)2O) (1310 mg, 6 mmol), and triethylamine (Et3N) ( 404 mg, 4 mmol) were dissolved in a solvent mixture of 20 mL of acetone and 10 mL of water. The reaction mixture was stirred at room temperature for 12 hours. Upon completion of the reaction, the solvent and triethylamine were removed using a rotary evaporator. The residue was extracted with dichloromethane (20 mL x 3). The organic phases were combined and concentrated to give the target product (2S)-2,5-bis[(tert-butoxycarbonyl)amino]pentanoic acid (2a) as a colorless liquid in 96% yield.
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