Synthesis
Benzyl chloroformate (1.63 mL, 11.45 mmol) was added slowly and dropwise to a stirred suspension of 6-aminohexanoic acid (1 g, 7.62 mmol) and K2CO3 (2.1 g, 15.2 mmol) in THF (20 mL). The reaction mixture was stirred at room temperature for 16 hours. Upon completion of the reaction, the reaction was quenched with ethyl acetate and deionized water. The aqueous phase was separated and the pH of the aqueous phase was adjusted to 2 with 4N HCl and subsequently extracted twice with ethyl acetate (10 mL). The organic phases were combined, dried with anhydrous Na2SO4, filtered and concentrated under reduced pressure. The resulting crude product of Cbz-6-aminohexanoic acid was used directly in the next reaction without further purification in 99% yield.
References
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[2] Bioorganic and Medicinal Chemistry Letters, 2017, vol. 27, # 15, p. 3332 - 3336
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[4] Synthetic Communications, 2004, vol. 34, # 13, p. 2415 - 2424
[5] Chemistry - A European Journal, 2008, vol. 14, # 27, p. 8169 - 8176