Nitric Acid → 1,2-Difluoro-4-nitrobenzene
Reaction equation
[N+:1]([O-:4])(O)=[O:2].S(=O)(=O)(O)O.[F:10][C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=1[F:17]>>[F:10][C:11]1[CH:16]=[C:15]([N+:1]([O-:4])=[O:2])[CH:14]=[CH:13][C:12]=1[F:17]Participants
4
Conditions
- Temperature
- -12 °C
Procedure
This material is prepared as described by R. W. Taft, G. B. Klingensmith, and S. Ehrenson, (J. Am. Chem. Soc., 87, 3620 (1965)). To a stirred mixture of 5.0 ml of concentrated nitric acid and 13.9 ml of concentrated sulfuric acid cooled to -12° C. is added 9.7 g (0.085 mole) of 1,2-difluorobenzene. A slight exotherm is observed and the mixture is cooled to -20° C. whereupon it solidifies. The mixture is stirred for 45 minutes at -5° to 0° and is then allowed to warm slowly to room temperature. After 1 hour the mixture is poured onto ice, and the mixture extracted with diethyl ether (3×75 ml). The combined ether extracts are washed with water, 10% aqueous Na2CO3, and water again. The ether solution is dried (MgSO4) and concentrated in vacuo without external heating to give the crude product (11.9 g), which is distilled (kugelrohr apparatus) to give 10.2 g of colorless liquid. The nmr spectrum of this material is consistent with the structure.