Sodium Carbonate → 7-bromo-2,3-dihydro-1,4-benzodioxin-6-amine

HRID 639013Notes

Reaction equation

HRID 639013 reaction equation
[O:1]1[C:6]2[CH:7]=[CH:8][C:9]([NH2:11])=[CH:10][C:5]=2[O:4][CH2:3][CH2:2]1.[Br:12]N1C(=O)CCC1=O.C(=O)([O-])[O-].[Na+].[Na+]>O1CCCC1.S(=O)(=O)(O)O>[Br:12][C:8]1[C:9]([NH2:11])=[CH:10][C:5]2[O:4][CH2:3][CH2:2][O:1][C:6]=2[CH:7]=1

Participants

6

Reactant 3

HCID 10340Sodium CarbonateHCID 67184N-bromobutanimideHCID 891481,4-Benzodioxan-6-ylamine

Product 1

HCID 49832297-bromo-2,3-dihydro-1,4-benzodioxin-6-amineYield 115.6%

Reagents, catalysts & solvents 2

HCID 1118Sulfuric AcidCatalystHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

A solution of 2,3-dihydro-benzo[1,4]dioxin-6-ylamine (80 g, 530 mmol, 1 eq) in tetrahydrofuran (1000 mL) at −78° C. was treated with concentrated sulfuric acid (50 drops) then N-bromosuccinimide (94.2 g, 530 mmol, 1 eq) was added over 0.5 hour. After the addition the mixture was stirred at −78° C. for 1 hour then treated with solid sodium carbonate (12 g, 113 mmol, 0.21 eq). The mixture was evaporated and the residue partitioned between ether and water. The organic extract was dried, filtered and evaporated to give to oil that was chromatographed on silica gel eluting with dichloromethane to afford oil (141 g, 92%). LC/MS (ES) m/z 230 (MH+ 91%); 1H-NMR (400 MHz, d6-DMSO), 6.85 (1H, s, CHCNH2), 6.34 (1H, s, CHCBr), 4.79 (2H, s, NH2), 4.16 (4H, dd, J=16, 2×(CH2O))

Workup

  1. additionAfter the addition the mixture
  2. customThe mixture was evaporated
  3. customthe residue partitioned between ether and water
  4. extractionThe organic extract
  5. customwas dried
  6. filtrationfiltered
  7. customevaporated
  8. customto give to oil that
  9. customwas chromatographed on silica gel eluting with dichloromethane

Sources & evidence

ORD record
ord-5f69fbe819ab4a0f98d02cfe685acf79
Source dataset
uspto-grants-2010_04
Patent number
US07691850B2

Reaction notes

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