Hydrogen Bromide → 7-Bromobenzo[d][1,3]dioxole-4-carboxylic acid

HRID 2182738Notes

Reaction equation

HRID 2182738 reaction equation
N[C:2]1[C:7]2[O:8][CH2:9][O:10][C:6]=2[C:5]([C:11]([OH:13])=[O:12])=[CH:4][CH:3]=1.N([O-])=O.[Na+].[BrH:18]>O.[Cu]Br>[Br:18][C:2]1[C:7]2[O:8][CH2:9][O:10][C:6]=2[C:5]([C:11]([OH:13])=[O:12])=[CH:4][CH:3]=1

Participants

6

Reactant 3

HCID 260Hydrogen Bromide2×HCID 219488227-Amino-1,3-dioxaindane-4-carboxylic acidHCID 23668193Sodium Nitrite

Product 1

HCID 219488907-Bromobenzo[d][1,3]dioxole-4-carboxylic acid

Reagents, catalysts & solvents 2

HCID 24593copper(I) bromideCatalystHCID 962WaterSolvent3×

Procedure

1.95 g of 7-amino-benzo[1,3]dioxole-4-carboxylic acid in 25 ml of hydrobromic acid (48%) and 20 ml of water are mixed at 0° C. with a solution of 760 mg of sodium nitrite in 4.2 ml of water. It is stirred for 15 minutes and then added to a solution of 2.07 g of copper(I) bromide in 5.5 ml of hydrobromic acid (48%). It is heated for 30 minutes to 100° C., added to water and extracted with ethyl acetate. It is washed with brine, dried with sodium sulfate and concentrated by evaporation in a vacuum. 2.88 g of 7-bromo-benzo[1,3]dioxole-4-carboxylic acid is obtained as a brown solid. The latter is reacted in 50 ml of DMF at 0° C. with 4.08 g of cesium carbonate and 0.8 ml of methyl iodide. It is stirred for 4 hours at room temperature, added to water, and extracted with ethyl acetate. It is washed several times with water and brine, dried and concentrated by evaporation in a vacuum. 1.81 g of 7-bromo-benzo[1,3]dioxole-4-carboxylic acid methyl ester is obtained as a red solid. The latter is dissolved in 5 ml of ether, and 10 ml of THF is added to a solution of 5.06 ml of methylmagnesium chloride (3 M in THF) and 6 ml of ether at room temperature. After 3.5 hours, the batch is added to 1N hydrochloric acid, extracted with ethyl acetate, washed with brine, dried and concentrated by evaporation in a vacuum. 1.79 g of 2-(7-bromo-1,3-benzodioxol-4-yl)-propan-2-ol is obtained as an orange-colored oil.

Workup

  1. temperatureIt is heated for 30 minutes to 100° C.
  2. extractionextracted with ethyl acetate
  3. washIt is washed with brine
  4. dry with materialdried with sodium sulfate
  5. concentrationconcentrated by evaporation in a vacuum

Sources & evidence

ORD record
ord-17b0c6e14ef244cf860a3ba9ac2d0f6d
Source dataset
uspto-grants-2005_05
Patent number
US06897224B2

Reaction notes

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