Triethylamine → tert-butyl (1S)-1-[(4-benzyl-2-vinyl-1-piperazinyl)carbonyl]-3-butenylcarbamate

Participants

Reaction Steps

(2S)-2-[(tert-butoxycarbonyl)amino]-4-pentenoic acid (466 mg, 2.17 mmol) and 1-benzyl-3-vinylpiperazine (436 mg, 2.17 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiinide hydrochloride (HOBT, 622 mg, 3.26 mmol) were combined with anhydrous CH2Cl2 (10 mL) at room temperature. Et3N (0.74 mL, 5.43 mmol) was added in one portion. The resulted solution was maintained at room temperature for 18 h at which time it was concentrated in vacuo to a volume of approximately 5 mL. Then the solution was purified by silica gel chromatography (SGC) eluting with 2:1 hex-EtOAc. The title compound (a pair of diastereomers) was obtained (171 mg, 20%) as a pale-yellow oil. 1H NMR (300 MHz, CDCl3) δ 7.31 (s, 5H), 5.99-5.82 (m, 1H), 5.81-5.65 (m, 1H), 5.50-5.00 (m, 6H), 4.75-4.23 (m, 2H), 3.70-3.37 (m, 3H), 3.11-2.79 (m, 2H), 2.59-2.00 (m, 4H), 1.42 (s, 9H) ppm. MS (CI) 400.6 (M+H).

Provenance & Evidence