Methylamine → [2-[2-Cyclopropylmethyl-4-(1-methylcarbamoyl-2-naphthalen-2-yl-ethyl)-3-oxo-piperazin-1-yl]-1-(4-fluorobenzyl)-2-oxo-ethyl]-carbamic acid tert-butyl ester

Participants

Reaction Steps

To a solution of 2-{4-[2-tert-butoxycarbonylamino-3-(4-fluorophenyl)-propionyl]-3-cyclopropylmethyl-2-oxo-piperazin-1-yl}-3-naphthalen-2-yl-propionic acid, 16, (114 mg, 0.18 mmol)) in DMF (2 mL) are added methylamine (2M, 0.11 mL, 0.22 mmol), 1-hydroxybenzotriazole (53 mg, 0.39 mmol), N-methylmorpholine (63 mg, 0.62 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (41 mg, 0.21 mmol) consecutively. The reaction mixture is stirred for 3 hours, quenched with aqueous NH4Cl and extracted several times with ethyl acetate. The combined extracts are dried over Na2SO4, filtered and concentrated in vacuo to a residue, which is purified over silica gel (hexanes/ethyl acetate, 1:4) to afford 108 mg (93% yield) of the desired product. 1H NMR (300 MHz, CD3OD, Rotamers) δ 7.73–7.86 (m, 3H), 7.70 (s, 1H), 7.38–7.52 (m, 3H), 7.14–7.30 (m, 2H), 6.91–7.04 (m, 2H), 5.54–5.72 (m, 1H), 4.50–4.78 (m, 2H), 4.28–4.40 (m, 0.3H), 4.03–4.15 (m, 0.7H), 3.72–3.81 (m, 0.3H), 3.58–3.68 (m, 0.3H), 3.42–3.53 (m, 2H), 3.12–3.32 (m, 2H), 2.70–3.00 (m, 6H), 1.41 (s, 5H), 1.34 (s, 4H), 0.66–1.30 (m, 2H), −0.60–−0.12 (m, 4.3H), −0.80–−0.68 (m, 0.7H); MS (ESMS) m/z 631.3 (M+H)+.

Provenance & Evidence