4-(6-Nitropyridin-3-yl)-3-oxopiperazine-1-carboxylic acid tert-butyl ester → Tert-butyl 4-(6-aminopyridin-3-yl)-3-oxopiperazine-1-carboxylate

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Reaction Steps

A 250-mL Parr reactor bottle was purged with nitrogen and charged with 10% palladium on carbon (50% wet, 100 mg dry weight) and a solution of 2c (500 mg, 1.55 mmol) in ethanol (20 mL). The bottle was attached to Parr hydrogenator, evacuated, charged with hydrogen gas to a pressure of 45 psi and shaken for 4 h. After this time, the hydrogen was evacuated, and nitrogen was charged into the bottle. Celite 521 (1.0 g) was added, and the mixture was filtered through a pad of Celite 521. The filter cake was washed with ethanol (2×30 mL), and the filtrate was concentrated under reduced pressure to afford a 95% yield of 2d (430 mg) as an amber film: 1H NMR (500 MHz, CDCl3) δ 7.98 (d, 1H, J=2.5 Hz), 7.38 (dd, 1H, J=8.5, 2.01 Hz), 6.52 (d, 1H, J=8.5 Hz), 4.54 (s, 1H), 4.26 (s, 2H), 3.78 (t, 2H, J=5.5 Hz), 3.67 (t, 2H, J=5.0 Hz), 1.50 (s, 9H); MS (ESI+) m/z 293.1 (M+H).

Provenance & Evidence