1-Hydroxybenzotriazole → (E)-N-(benzofuran-5-ylmethyl)-N-methyl-3-(7-oxo-5,6,7,8-tetrahydro-1,8-naphthyridin-3-yl)acrylamide

Participants

Reaction Conditions

Reaction Steps

To a solution of benzofuran-5-yl-N-methylmethanamine (297 mg, 1.84 mmol), 3-(7-oxo-5,6,7,8-tetrahydro-[1,8]naphthyridin-3-yl)-acrylic acid hydrochloride (474 mg, 1.86 mmol), HOBt (252 mg, 1.86 mmol) and DIPEA (1.32 mL, 7.58 mmol) in anhydrous DMF (30 mL) was added EDC hydrochloride (357 mg, 1.86 mmol). The mixture was stirred overnight at 40° C. Water (70 mL) was added and the solution was stirred for 1 h. The reaction mixture was extracted with ethyl acetate (3×100 mL). Combined organic layers were washed with water (50 mL) and brine (50 mL) and concentrated to give a red solid which was purified by column chromatography (silica gel, 5% MeOH/CH2Cl2) to afford (E)-N-(benzofuran-5-ylmethyl)-N-methyl-3-(7-oxo-5,6,7,8-tetrahydro-1,8-naphthyridin-3-yl)acrylamide (381 mg, 57%) as a red solid and a mixture of amide rotomers: 1H NMR (400 MHz, DMSO-d6) δ 10.64-10.62 (m, 1H), 8.36-8.33 (m, 1H), 8.07 (s, 1H), 7.97 (s, 1H), 7.59-7.49 (m, 3H), 7.38-7.17 (m, 2H), 6.94 (m, 1H), 4.89-4.69 (m, 2H), 3.10-2.85 (m, 5H), 2.54-2.52 (m, 2H); ESI MS m/z 362 [C21H19N3O3+H]+.

Provenance & Evidence