Sodium Hydroxide → (e)-6-{2-[Methyl-(3-methyl-benzo[b]thiophen-2-ylmethyl)carbamoyl]vinyl}-2-oxo-1,2-dihydro-[1,8]naphthyridine-3-carboxylic acid sodium salt

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To a suspension of (E)-6-{2-[methyl-(3-methyl-benzo[b]thiophen-2-ylmethyl)carbamoyl]vinyl}-2-oxo-1,2-dihydro-[1,8]naphthyridine-3-carboxylic acid ethyl ester (349 mg, 0.76 mmol) in MeOH (10 mL) and CH2Cl2 (5 mL) was added NaOH (1.53 mL of a 0.995 M solution in H2O, 1.53 mmol) dropwise. The mixture was stirred at room temperature overnight. The solid was collected by filtration and then dried under vacuum at 50° C. for 2 d. Trituration with 5:1 MeCN/H2O gave the title compound (85 mg, 25%) as an off-white solid and as a mixture of amide rotamers: 1H NMR (300 MHz, DMSO-d6+TFA-d) δ 9.15 (s, 1H), 8.85 (s, 2H), 7.88 (d, J=7.5 Hz, 1H), 7.76-7.58 (m, 2H), 7.46-7.34 (m, 3H), 5.15-4.92 (m, 2H), 3.20-2.98 (m, 3H), 2.44 (s, 3H); MS (ESI) m/e 434 (M−Na+2H)+.

Provenance & Evidence