1,2-Dibromoethane → 7-Fluoro-5-nitro-2,3-dihydrobenzo[b][1,4]dioxine

HRID 1054444Notes

Reaction equation

HRID 1054444 reaction equation
C([O-])([O-])=O.[K+].[K+].[F:7][C:8]1[CH:13]=[C:12]([OH:14])[C:11]([OH:15])=[C:10]([N+:16]([O-:18])=[O:17])[CH:9]=1.Br[CH2:20][CH2:21]Br>CN(C=O)C.C(OCC)(=O)C>[F:7][C:8]1[CH:9]=[C:10]([N+:16]([O-:18])=[O:17])[C:11]2[O:15][CH2:21][CH2:20][O:14][C:12]=2[CH:13]=1

Participants

6

Reactant 3

HCID 78391,2-DibromoethaneHCID 11430Potassium CarbonateHCID 688163705-Fluoro-3-nitrobenzene-1,2-diol

Product 1

HCID 688171507-Fluoro-5-nitro-2,3-dihydrobenzo[b][1,4]dioxineYield 99%

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 8857Ethyl AcetateSolvent

Procedure

K2CO3 (15.27 g, 110.6 mmol) was added to a solution of 5-fluoro-3-nitrobenzene-1,2-diol (5 g, 28.9 mmol) in DMF (35 mL) followed by the addition of 1,2-Dibromoethane (13.63 g, 6.25 mL, 72.5 mmol) and stirring was continued at 80° C. for 2 h. Reaction mixture was diluted with ethyl acetate, washed with cold water, dried over anhydrous sodium sulphate and concentrated under reduced pressure to afford the crude, which was purified by MPLC (silica gel, Mobile Phase: ethyl acetate in n-Hexane 0 to 5% as eluant) to afford 7-fluoro-5-nitro-2,3-dihydrobenzo[b][1,4]dioxine (Int-26) (5.7 g, 85% yield) as pale yellow solid. 1H NMR (300 MHz, CDCl3) δ 7.3-7.2 (1H, dd), 6.9-6.8 (1H, dd), 4.4 (4H, s) ppm.

Workup

  1. customReaction mixture
  2. washwashed with cold water
  3. dry with materialdried over anhydrous sodium sulphate
  4. concentrationconcentrated under reduced pressure
  5. customto afford the crude, which
  6. customwas purified by MPLC (silica gel, Mobile Phase: ethyl acetate in n-Hexane 0 to 5% as eluant)

Sources & evidence

ORD record
ord-ecd71a84c7fe4fe9aa8a3f60bc7be679
Source dataset
uspto-grants-2016_07
Patent number
US09394305B2

Reaction notes

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