2-Thiophenecarbonyl chloride → 1-Benzyl-2-oxo-4-[4-(thiophene-2-carbonyl)-piperazin-1-yl]-1,2-dihydro-[1,8]-naphthyridine-3-carbonitrile

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Reaction Steps

2-Thiophene carbonyl chloride (0.16 mL, 1.5 mmol) was added to a stirred solution of 1-benzyl-2-oxo-4-piperazin-1-yl-1,2-dihydro-[1,8]-naphthyridine-3-carbonitrile (9) (345 mg, 1 mmol) in pyridine at 0° C. The solution was allowed to come at room temperature and further stirred overnight at room temperature. The solution was poured into ice water and the solids formed were filtered, washed by water, and dried. The crude product was purified by flash chromatography eluting with linear gradients of 0-3% MeOH in CH2Cl2 to yield 273 mg (45%) of 1-benzyl-2-oxo-4-[4-(thiophene-2-carbonyl)-piperazin-1-yl]-1,2-dihydro-[1,8]-naphthyridine-3-carbonitrile (10) as white solids. MP: 263° C.; 1H-NMR (DMSO-d6): δ 3.75 (m, 4H), 3.94 (m, 4H), 5.58 (s, 2H), 7.15 (dd, J=3.5, 4.8 Hz, 1H), 7.19-7.29 (m, 5H), 7.40 (dd, J=4.8, 8.0 Hz, 1H), 7.52 (dd, J=4.0, 5.2 Hz, 1H), 8.35 (dd, J=1.6, 8.0 Hz, 1H), 8.72 (dd, J=1.6, 8.0 Hz, 1H); EIMS: 456 (M+1). Anal. C25H21N5O2S (C,H,N).

Provenance & Evidence