N-α-Boc-propargyl-lysine-OH synthesis

Yield:-

Reaction Conditions:

in tetrahydrofuran;NaOH;ethyl acetate;

Steps:

3 (S)-2-(tert-butoxycarbonylamino)-6-((prop-2-ynyloxy)carbonylamino)hexanoic acid (9)

Boc-Lys-OH (500 mg, 2.03 mmol) was dissolved in 1 M NaOH (5 mL) and THF (5 mL) and cooled to 0° C. Propargyl chloroformate (158.4 mL, 192.5 mg, 1.62 mmol) was added dropwise over 5 minutes and the reaction was allowed to stir for 10 hours at room temperature. The solution was then cooled to 0° C. again, washed with ice-cold Et₂O (50 mL), acidified with ice-cold 1 M HCl (50 mL), and was extracted with ice-cold EtOAc (2*30 mL). The combined organic layers were dried over Na₂SO₄ and the solvents were evaporated to clean give 9 (442 mg, 1.35 mmol) as a white foam in 83% yield. ¹H NMR (CDCl₃): δ=1.33-1.80 (m, 14H), 2.45 (s, 1H), 3.15 (m, 2H), 4.23 (m, 1H), 4.62-4.68 (m, 2H), 5.25-5.55 (m, 2H), 6.20-6.47 (m, 1H), 11.03 (s, 1H). ¹³C NMR (CDCl₃): δ=22.5, 28.5, 29.3, 32.1, 40.8, 52.6, 53.2, 74.8, 78.5, 80.3, 156.0, 157.3, 176.7. HRMS: m/z calcd for C₁₅H₂₄N₂O₆ [M+Na]⁺: 351.15266. found: 351.15245.

References:

US2012/77948,2012,A1