Calcium Carbonate → Methyl 3-amino-5-bromothiophene-2-carboxylate

HRID 1392936Notes

Reaction equation

HRID 1392936 reaction equation
[CH3:1][O:2][C:3]([C:5]1[S:6][CH:7]=[CH:8][C:9]=1[NH2:10])=[O:4].[Br-:11].[Br-].[Br-].C1([N+](C)(C)C)C=CC=CC=1.C1([N+](C)(C)C)C=CC=CC=1.C1([N+](C)(C)C)C=CC=CC=1.C(=O)([O-])[O-].[Ca+2]>C(Cl)Cl.CO>[NH2:10][C:9]1[CH:8]=[C:7]([Br:11])[S:6][C:5]=1[C:3]([O:2][CH3:1])=[O:4]

Participants

6

Reactant 3

HCID 10112Calcium CarbonateHCID 89652Methyl 3-amino-2-thiophenecarboxylateHCID 17977687Phenyltrimethylammonium bromide dibromide

Product 1

HCID 20158931Methyl 3-amino-5-bromothiophene-2-carboxylateYield 57.2%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 6344DichloromethaneSolvent

Procedure

Methyl-3-amino-2-thiophene carboxylate (1 eq. 25 g) was dissolved in 250 ml methylene chloride and 250 ml of methanol. Phenyl trimethylammonium tribromide (3 eq. 180 g) was added followed by calcium carbonate (4 eq. 63.75 g) and the reaction was left stirring at room temperature overnight. The calcium carbonate was filtered off and the filtrate concentrated down and water (750 ml) was added followed by ethyl acetate (1 L). The ethyl acetate layer was washed with more water, sodium thiosulfate, saturated sodium bicarbonate and saturated sodium chloride. The organic layer was dried over magnesium sulfate, filtered and the filtrate was concentrated under reduced pressure. The crude product was purified by flash chromatography to yield 21.46 g (57%) of methyl 3-amino-5-bromothiophene-2-carboxylate as a light brown oil, MH+=238.1.

Workup

  1. waitthe reaction was left
  2. filtrationThe calcium carbonate was filtered off
  3. concentrationthe filtrate concentrated down and water (750 ml)
  4. additionwas added
  5. washThe ethyl acetate layer was washed with more water, sodium thiosulfate, saturated sodium bicarbonate and saturated sodium chloride
  6. dry with materialThe organic layer was dried over magnesium sulfate
  7. filtrationfiltered
  8. concentrationthe filtrate was concentrated under reduced pressure
  9. customThe crude product was purified by flash chromatography

Sources & evidence

ORD record
ord-a343a50d408b4ebead26a81fb81647d1
Source dataset
uspto-grants-2008_03
Patent number
US07345046B2

Reaction notes

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