1,2-Dibromoethane → 2-[3-Cyclopropylmethyl-4-(2-nitro-benzene-sulfonyl)-2-oxo-piperazin-1-yl]-3-naphthalen-2-yl-propionic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-[3-cyclopropyl-2-(2-nitro-benzenesulfonylamino)-propionylamino]-3-naphthalen-2-yl-propionic acid methyl ester, 12, (3.46 g, 6.59 mmol) and 1,2-dibromoethane (12.38 g, 65.9 mmol) in DMF (40 mL) is added potassium carbonate (9.10 g, 65.8 mmol). The reaction mixture is stirred for 15 hours at 65° C., cooled and quenched with aqueous NH4Cl solution. The mixture is then extracted several times with EtOAc and the combined extracts dried over Na2SO4 and concentrated in vacuo. The resulting residue is purified over silica gel (hexanes/EtOAc, 1:2) to afford 3.57 g (98% yield) of the desired product. 1H NMR (300 MHz, CD3OD) δ 8.01–8.08 (m, 1H), 7.58–7.84 (m, 7H), 7.43–7.52 (m, 2H), 7.35 (dd, J=8.4 Hz, 1H), 5.38 (dd, J=11.7, 4.8 Hz, 1H), 4.33–4.44 (m, 1H), 3.76–3.88 (m, 1H), 3.69 (s, 3H), 3.21–3.66 (m, 4H), 2.99–3.14 (m, 1H), 1.40–1.53 (m, 1H), 1.02–1.16 (m, 1H), −0.14–−0.02 (m, 3H), −0.34–−0.20 (m, 2H); MS (ESMS) m/z 552.2 (M+H)+.

Provenance & Evidence