Water → 5-Nitro-2,3-dihydro-1,4-benzodioxine

HRID 1487198Notes

Reaction equation

HRID 1487198 reaction equation
[N+:1]([C:4]1[CH:9]=[CH:8][CH:7]=[C:6]([OH:10])[C:5]=1[OH:11])([O-:3])=[O:2].C(=O)([O-])[O-].[K+].[K+].Br[CH2:19][CH2:20]Br.O>CN(C=O)C>[N+:1]([C:4]1[C:5]2[O:11][CH2:20][CH2:19][O:10][C:6]=2[CH:7]=[CH:8][CH:9]=1)([O-:3])=[O:2]

Participants

6

Reactant 4

HCID 962WaterHCID 78391,2-DibromoethaneHCID 11430Potassium CarbonateHCID 4675622Nitrocatechol

Product 1

HCID 122313185-Nitro-2,3-dihydro-1,4-benzodioxineYield 62.2%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
110 °C

Procedure

To a solution of 3-nitrobenzene-1,2-diol (11 g, 0.071 mol) in N,N′-dimethylformamide (500 mL) was added potassium carbonate (29 g, 0.0.213 mol) followed by 1,2-dibromoethane (14.7 g, 0.078 mol). The mixture was heated at 110° C. for 2 hours. After cooled to room temperature, the mixture was poured into water and then extracted with ether. The organic phases were combined and dried over anhydrous sodium sulfate, filtrated and concentrated to give a crude product, which was purified by silica gel column chromatography (petroleum ether/ethyl acetate 20/1) to afford the product 5-nitro-2,3-dihydrobenzo[b][1,4]dioxine (8 g, yield 62%). 1H NMR (400 MHz, CDCl3) δ ppm 7.48-7.50 (dd, 1H, J=1.6 Hz, 8.4 Hz), 7.09-7.12 (dd, 1H, J=1.6 Hz, 8.4 Hz), 6.88-6.92 (t, 1H, J=8.4 Hz), 4.40-4.42 (m, 2H), 4.34-4.36 (m, 2H).

Workup

  1. temperatureAfter cooled to room temperature
  2. extractionextracted with ether
  3. dry with materialdried over anhydrous sodium sulfate
  4. filtrationfiltrated
  5. concentrationconcentrated
  6. customto give a crude product, which
  7. customwas purified by silica gel column chromatography (petroleum ether/ethyl acetate 20/1)

Sources & evidence

ORD record
ord-7876a5b48d954ac8a30c29b61e52f297
Source dataset
uspto-grants-2016_08
Patent number
US09428508B2

Reaction notes

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