Nitric Acid → 2-Amino-5-chloro-3-nitropyridine

Temperature

55 °C

Concentrated H2SO4 (97%, 300 mL) was placed in a 500 mL three-neck round-bottom flask. The flask was equipped with an internal thermometer, a glass funnel and stopper, and placed in a salt/ice bath. When the internal temperature reached 5° C., 2-amino-5-chloropyridine (101) (77.2 g, 0.600 mol) was added over 1 h with stirring. The suspension was then stirred at room temperature to dissolve the rest of the solid. The resulting solution was heated to 55° C. HNO3 (70%, 40.5 mL, d=1.41, 0.634 mol) was added dropwise through an addition funnel as to maintain the internal temperature at 57°±3° C. The reaction solution was poured over ice (1.5 kg), and the resulting mixture partially neutralized with 40% NaOH (~600 mL). The mixture was filtered to leave a yellow/orange solid. This solid was washed by resuspension in water (600 mL). The mixture was filtered, and the resulting solid was dried in the oven for 48 h to yield the title compound as an orange/yellow solid (66.3 g, 63.8%), mp 184°-6° C. (Lit., 190°-3° C., Vaughan et al., J. Amer. Chem. Soc. 71:1885 (1949)); 1H NMR (CDCl3): δ6.69 (bs, 2H), 8.33 (d, J=1.5 Hz, 1H), 8.43 (d, J=1.5 Hz, 1H).

1. customThe flask was equipped with an internal thermometer, a glass funnel and stopper
2. customreached 5° C.
3. stirringThe suspension was then stirred at room temperature
4. dissolutionto dissolve the rest of the solid
5. temperatureto maintain the internal temperature at 57°±3° C
6. filtrationThe mixture was filtered
7. customto leave a yellow/orange solid
8. washThis solid was washed by resuspension in water (600 mL)
9. filtrationThe mixture was filtered
10. customthe resulting solid was dried in the oven for 48 h

ORD record

ord-bd3c16d6a9364f62bc974a5d6654ce70

Source dataset

uspto-grants-1998_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05801183