Nitric Acid → 2,6-Difluoro-3-nitrobenzaldehyde

Temperature

5 °C

To stirring 69% nitric acid (6.48 ml, 93.59 mmol) cooled to 5° C. was added concentrated sulfuric acid (4.16 ml, 78.11 mmol) dropwise, keeping the internal temperature below 8° C. After complete addition stirring was continued for 15 minutes. This mixture was added to a solution of 2,6-difluorobenzaldehyde (10 g, 70.37 mmol) in concentrated sulfuric acid (50 ml) dropwise keeping the internal temperature below 10° C. After complete addition the mixture was stirred at 5° C. for 15 minutes then allowed to warm to room temperature over 90 minutes. The reaction mixture was poured onto ice-water (400 ml) and the resulting solid stirred for 1 hour. The solid was collected by filtration, washed with water and dried under vacuum to yield the title compound (9.27 g, 70%). 1H NMR (DMSO-d6, 300 MHz): 10.21 (1 H, t, J=1.02 Hz), 8.52 (1 H, ddd, J=9.38, 8.60, 5.51 Hz), 7.51 (1 H, td, J=9.53, 1.76 Hz).

1. customthe internal temperature below 8° C
2. additionAfter complete addition
3. customthe internal temperature below 10° C
4. additionAfter complete addition the mixture
5. stirringwas stirred at 5° C. for 15 minutes
6. temperatureto warm to room temperature over 90 minutes
7. additionThe reaction mixture was poured onto ice-water (400 ml)
8. stirringthe resulting solid stirred for 1 hour
9. filtrationThe solid was collected by filtration
10. washwashed with water
11. customdried under vacuum

ORD record

ord-f4458c7c2cc04a2888743232e2db4434

Source dataset

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08841462B2