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

HRID 2167731Notes

Reaction equation

HRID 2167731 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]dioxine

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-51) as pale yellow solid. 1H NMR (300 MHz, CDCl3) δ ppm 7.3-7.2 (1H, dd), 6.9-6.8 (1H, dd), 4.4 (4H, s).

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-86495fda2f3741e191132791a323e774
Source dataset
uspto-grants-2015_06
Patent number
US09045478B2

Reaction notes

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