Hydrogen Peroxide → 5-Bromo-3-methylthiophene-2-carboxylic acid

HRID 2368707Notes

Reaction equation

HRID 2368707 reaction equation
P([O-])([O-])([O-])=O.[Na+].[Na+].[Na+].[OH:9]O.[Br:11][C:12]1[S:16][C:15]([CH:17]=[O:18])=[C:14]([CH3:19])[CH:13]=1.[Na]>O.C(#N)C>[Br:11][C:12]1[S:16][C:15]([C:17]([OH:9])=[O:18])=[C:14]([CH3:19])[CH:13]=1

Participants

7

Reactant 4

HCID 784Hydrogen PeroxideHCID 24243Trisodium PhosphateHCID 5360545SodiumHCID 151154075-Bromo-3-methylthiophene-2-carbaldehyde

Product 1

HCID 181766635-Bromo-3-methylthiophene-2-carboxylic acid

Reagents, catalysts & solvents 2

HCID 962WaterSolvent2×HCID 6342AcetonitrileSolvent

Procedure

A solution of 50.4 g of sodium phosphate, monobasic, (1.5 mol) in 600 mL of water, followed by 131 mL of a 35% hydrogen peroxide solution were added to a solution of 5-bromo-3-methyl-thiophene-2-carbaldehyde (300 g, 1.46 mol), example 1-a, in 1.5 L of acetonitrile. The resultant solution was cooled to 0° C. with an external ice bath, and a solution of 170 g of sodium perchlorite in 2 L of water was added dropwise over a 2 hour period. The reaction mixture was allowed to warm to room temperature, and stirred for 1.5 h. The reaction was quenched with the addition of 10 g of sodium sulfite, and stirred for 15 min. The mixture was acidified to ca. pH 3 with 1 N HCl solution, and cooled to 0° C. An off-white precipitate was collected on a medium glass filter funnel. The precipitate was washed twice with water and then dissolved in ethyl acetate. The aqueous acetonitrile solution was extracted once with ethyl acetate, and the organic fraction was combined with the pervious ethyl acetate solution. The combined organic fractions were dried over anhydrous magnesium sulfate and concentrated under hi-vacuum to produce 305 g of a tan solid. 1H NMR (CDCl3, 200 MHz): δ=6.91 (s, 1H), 2.52 (s, 3H); MS: (−) m/z 218.92, 220.94 (M−1, 79Br/81Br)

Workup

  1. customThe reaction was quenched with the addition of 10 g of sodium sulfite
  2. stirringstirred for 15 min
  3. temperaturecooled to 0° C
  4. customAn off-white precipitate was collected on a medium glass
  5. filtrationfilter funnel
  6. washThe precipitate was washed twice with water
  7. dissolutiondissolved in ethyl acetate
  8. extractionThe aqueous acetonitrile solution was extracted once with ethyl acetate
  9. dry with materialThe combined organic fractions were dried over anhydrous magnesium sulfate
  10. concentrationconcentrated under hi-vacuum

Sources & evidence

ORD record
ord-eb8840fd20c54dacacd00be03307f528
Source dataset
uspto-grants-2014_04
Patent number
US08703795B2

Reaction notes

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