1,2-Dibromo-1,1,2,2-tetrafluoroethane → 7-Bromo-6-chloro-3-(2-fluorophenyl)-1,2,4-triazolo[4,3-b]pyridazine

HRID 1369437

Reaction equation

HRID 1369437 reaction equation
[Cl:1][C:2]1[C:3]([Si](C)(C)C)=[CH:4][C:5]2[N:6]([C:8]([C:11]3[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=3[F:17])=[N:9][N:10]=2)[N:7]=1.[Br:22]C(F)(F)C(F)(F)Br>CCCC[N+](CCCC)(CCCC)CCCC.C1C=CC([Sn-](F)(F)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1COCC1.ClCCl>[Br:22][C:3]1[C:2]([Cl:1])=[N:7][N:6]2[C:8]([C:11]3[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=3[F:17])=[N:9][N:10]=[C:5]2[CH:4]=1

Participants

6

Reactant 2

HCID 313011,2-Dibromo-1,1,2,2-tetrafluoroethaneHCID 154861756-Chloro-3-(2-fluorophenyl)-7-(trimethylsilyl)-[1,2,4]triazolo[4,3-b]pyridazine

Product 1

HCID 154861767-Bromo-6-chloro-3-(2-fluorophenyl)-1,2,4-triazolo[4,3-b]pyridazineYield 88%

Reagents, catalysts & solvents 3

HCID 1784490421-Butanaminium, N,N,N-tributyl-, (TB-5-11)-difluorotriphenylstannate(1-) (1:1)CatalystHCID 6344DichloromethaneSolventHCID 8028TetrahydrofuranSolvent

Procedure

Tetrabutylammonium difluorotriphenylstannate (6.8 g, 10.8 mmol) was added to a suspension of 6-chloro-3-(2-fluorophenyl)-7-(trimethylsilyl)-1,2,4-triazolo[4,3-b]pyridazine (3.17 g, 9.88 mmol), prepared as in Example 25 Step c), and 1,2-dibromotetrafluoroethane (6.0 ml, 50 mmol) in anhydrous THF (75 ml) and the mixture was stirred at room temperature under nitrogen for 18 h. The mixture was diluted with dichloromethane (100 ml), filtered and the filtrate was concentrated. Flash column chromatography on silica gel, eluting with 50-100% EtOAc-hexane, gave 7-bromo-6-chloro-3-(2-fluorophenyl)-1,2,4-triazolo[4,3-b]pyridazine (2.84 g, 88%) as an off-white solid; 1H NMR (360 MHz, CDCl3) δ7.31 (1H, dd, J=10 and 10 Hz), 7.36 (1H, ddd, J=8, 8 and 1 Hz), 7.57-7.63 (1H, m), 7.87 (1H, ddd, J=7, 7 and 2 Hz), 8.49 (1H, s); MS (ES+) m/e 327/329/331 [MH]+.

Workup

  1. filtrationfiltered
  2. concentrationthe filtrate was concentrated
  3. washFlash column chromatography on silica gel, eluting with 50-100% EtOAc-hexane

Sources & evidence

ORD record
ord-bfe563adb7d34089ba47ecc4ceee669c
Source dataset
uspto-grants-2003_06
Patent number
US06579875B1

Linked notes

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