188348-00-7

peptide synthesis

reaction type: Boc solid-phase peptide synthesis

General procedure for the synthesis of tert-butyl (R)-(1-cyclohexyl-2-hydroxyethyl)carbamate from (R)-2-((tert-butoxycarbonyl)amino)-2-cyclohexylacetic acid: N-(tert-butoxycarbonyl)cyclohexylglycine (2.0 g, 7.77 mmol) was dissolved in anhydrous THF (10 mL) and the solution was cooled to 0 °C. Borane-THF solution (1 M solution of THF, 15.5 mL, 15.5 mmol) was added slowly under stirring. After addition, the reaction mixture was gradually warmed to room temperature and stirring was continued for 2 hours. Upon completion of the reaction, the reaction was carefully quenched with methanol (5 mL), followed by evaporation of the volatiles under reduced pressure. The organic layer was separated by partitioning the residue between water and ethyl acetate. The organic layer was washed sequentially with saturated aqueous sodium bicarbonate, brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to afford the target product tert-butyl-(1-cyclohexyl-2-hydroxyethyl)carbamate (1.26 g, 66.7% yield). Mass spectrum (chemical ionization) m/z 144.20 (MH+-BOC).

[1] Journal of Medicinal Chemistry, 2004, vol. 47, # 14, p. 3483 - 3486
[2] Patent: WO2005/7164, 2005, A1. Location in patent: Page 28-29
[3] Patent: WO2005/7165, 2005, A1. Location in patent: Page 36
[4] Bioorganic and Medicinal Chemistry Letters, 2004, vol. 14, # 4, p. 865 - 868