2-Hydroxy-3-Nitro-6-Chloropyridine synthesis

Yield:92138-35-7 80%

Reaction Conditions:

Stage #1: 2-amino-6-chloro-3-nitropyridinewith sulfuric acid at 0; for 0.166667 h;
Stage #2: with sodium nitrite in water at 0; for 0.666667 h;

Steps:

5

Intermediate 5 6-Chloro-3-nitropyridin-2(l//)-one To ice cold concentrated sulphuric acid was added 6-chloro-3 -nitro-pyridin-2-ylamine (Intermediate 4, 5 g, 28 mmol), and the reaction mixture was stirred for 10 min at 0 ⁰C. A solution OfNaNO₂ (4 g, 58 mmol in 30 mL of water) was added slowly over a period of 10 min maintaining the temperature at 0⁰C, then the mixture was stirred for 30 min at the same temperature. The reaction mixture was poured onto ice cold water (150 mL), the precipitate that formed was collected by filtration, washed with cold water (2x50 mL) and dried under vacuum to provide 6-chloro-3-nitropyridin-2(lf/)-one in 80% yield (4 g, 23 mmol) as yellow color solid. MS (ES): 172.9 (M-I) for C₅H₃ClN₂O₃.¹H-NMR (DMSO-d_6, 400 MHz): δ 7.06 (d, J= 8.3 Hz, IH), 8.40-8.43 (m, IH).

References:

WO2009/27732,2009,A1 Location in patent:Page/Page column 70