Hydrochloric Acid → HCID 71470358, compound

Participants

Reaction Conditions

Reaction Steps

L-Boc-Lys(Boc)-OH (0.31 g, 0.91 mmol) and compound (19) (0.20 g, 0.46 mmol) were dissolved in 2 mL of pyridine. The solution was cooled to −25° C. and phosphorus oxychloride (0.14 g, 0.91 mmol) was added dropwise with vigorous stirring. After stirring for 30 min. at -25° C., the reaction mixture was stirred at room temperature for 10 h. The reaction mixture was quenched with ice/water and extracted with EtOAc. The organic layer was washed with sat. NaHSO4 three times, dried with Na2SO4 and was concentrated in vacuo. The crude product was subjected to chromatography with CH3CN:CH2Cl2=1:40 and the Boc-protected product was obtained in 26% yield. Into the solution of the Boc-protected lysine conjugate (85 mg, 0.11 mmol) in THF was gaseous HCl bubbled at 0° C. for 1 hr and the solution was stirred for 1 hour at room temperature. The solvent was evaporated and the desired product (46 mg, 65%) was purified by recrystallization with EtOH: 1H-NMR (300 MHz, CD3OD) δ 8.07 (dd, J=6.3 Hz, J=3.0 Hz, 1H), 7.69 (m, 2H), 4.26 (dd, J=7.5 Hz, J=5.4 Hz, 1H), 2.98 (t, J=H7.2 Hz, 2H), 2.01-2.21 (m, 2H), 1.75-1.81 (m, 2H), 1.60-1.75 (m, 2H).

Provenance & Evidence