1-Hydroxybenzotriazole → (E)-N-(benzo[b]thiophen-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 benzo[b]thiophen-5-yl-N-methylmethanamine (260 mg, 1.47 mmol), 3-(7-oxo-5,6,7,8-tetrahydro-[1,8]naphthyridin-3-yl)-acrylic acid hydrochloride (377 mg, 1.48 mmol), HOBt (200 mg, 1.48 mmol) and DIPEA (1.05 mL, 6.03 mmol) in anhydrous DMF (24 mL) was added EDC hydrochloride (284 mg, 1.48 mmol). The mixture was stirred overnight at 40° C. Water (50 mL) was added and the solution was stirred for 1 h. The reaction mixture was extracted with ethyl acetate (3×80 mL). Combined organic layers were washed with water (50 mL) and brine (50 mL) and concentrated to give an orange solid which was purified by column chromatography (silica gel, 5% MeOH/CH2Cl2) to afford (E)-N-(benzo[b]thiophen-5-ylmethyl)-N-methyl-3-(7-oxo-5,6,7,8-tetrahydro-1,8-naphthyridin-3-yl)acrylamide (430 mg, 78%) as a pink solid and a mixture of amide rotomers: 1H NMR (400 MHz, DMSO-d6) δ 10.67-10.64 (m, 1H), 8.37-8.33 (m, 1H), 8.08-8.05 (m, 1H), 8.00-7.95 (m, 1H), 7.75-7.71 (m, 2H), 7.56-7.52 (m, 1H), 7.45-7.43 (m, 1H), 7.37-7.22 (m, 2H), 4.93-4.73 (m, 2H), 3.12-2.86 (m, 5H), 2.54-2.51 (m, 2H); ESI MS m/z 378 [C21H19N3O2S+H]+.

Provenance & Evidence