Bromoform → 5-Bromo-4-nitro-1-(2,3,5,6-tetrafluoro-4-trifluoromethyl-phenyl)-pyrazole
Reaction equation
C(ON=O)(C)(C)C.N[C:9]1[N:13]([C:14]2[C:19]([F:20])=[C:18]([F:21])[C:17]([C:22]([F:25])([F:24])[F:23])=[C:16]([F:26])[C:15]=2[F:27])[N:12]=[CH:11][C:10]=1[N+:28]([O-:30])=[O:29].C(Br)(Br)[Br:32]>>[Br:32][C:9]1[N:13]([C:14]2[C:19]([F:20])=[C:18]([F:21])[C:17]([C:22]([F:25])([F:24])[F:23])=[C:16]([F:26])[C:15]=2[F:27])[N:12]=[CH:11][C:10]=1[N+:28]([O-:30])=[O:29]Participants
Procedure
21.6 ml (0.18 mol) of t-butylnitrite are added dropwise to 20.6 g (0.06 mol) of 5-amino-4-nitro-1-(2,3,5,6-tetrafluoro-4-trifluoromethyl-phenyl)-pyrazole in 100 ml (1.125 mol) of bromoform in the course of 10 minutes, while stirring, whereupon the temperature of the reaction mixture rises to 50° C. When the addition has ended, the mixture is stirred at the reflux temperature for a further two hours and is concentrated in vacuo, the residue is taken up in methylene chloride, the mixture is washed several times with saturated sodium bicarbonate solution, 2n-hydrochloric acid and water and dried over sodium sulphate and the solvent is stripped off in vacuo. 22 g (89.9% of theory) of 5-bromo-4-nitro-1-(2,3,5,6-tetrafluoro-4-trifluoromethyl-phenyl)-pyrazole are obtained as a brown oil.
Workup
- customrises to 50° C
- additionWhen the addition
- stirringthe mixture is stirred at the reflux temperature for a further two hours
- concentrationis concentrated in vacuo
- washthe mixture is washed several times with saturated sodium bicarbonate solution, 2n-hydrochloric acid and water
- dry with materialdried over sodium sulphate
Sources & evidence
- ORD record
- ord-369411d8c0124181964c83686fc0f8d1
- Source dataset
- uspto-grants-1988_11
- Patent number
- US04787930
Reaction notes
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