Lithium hydroxide, monohydrate → 3-Amino-5-phenylthiophene-2-carboxylic acid

HRID 2193896Notes

Reaction equation

HRID 2193896 reaction equation
C[O:2][C:3]([C:5]1[S:6][C:7]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)=[CH:8][C:9]=1[NH2:10])=[O:4].O[Li].O>C1COCC1.CO.O>[NH2:10][C:9]1[CH:8]=[C:7]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)[S:6][C:5]=1[C:3]([OH:4])=[O:2]

Participants

4

Reactant 2

HCID 168937Lithium hydroxide, monohydrateHCID 700562Methyl 3-amino-5-phenylthiophene-2-carboxylate

Product 1

HCID 198432823-Amino-5-phenylthiophene-2-carboxylic acidYield 88.2%

Reagents, catalysts & solvents 1

HCID 21892291Methanol tetrahydrofuran waterSolvent

Conditions

Temperature
85 °C

Procedure

To a suspension of 3-Amino-5-phenyl-thiophene-2-carboxylic acid methyl ester (5 g, 21.459 mmol) in a mixture of THF:MeOH:H2O (3:2:1, 75 mL), 1N aqueous solution of LiOH.H2O (64 mL, 64.378 mmol) was added. The reaction mixture was stirred at 85° C. (external temperature) for 4 h. Solvents were removed under reduced pressure and the residue was partitioned between water and ethyl acetate. The water layer was separated and acidified with 1N HCl solution and then ethyl acetate was added to it. The organic phase was separated, dried (Na2SO4) and concentrated to obtain 3-Amino-5-phenyl-thiophene-2-carboxylic acid (4.15 g, 88%) as a yellowish solid. 1H NMR (DMSO-D6, 400 MHz): 7.59 (d, 2H), 7.40 (m, 3H), 6.92 (s, 1H).

Workup

  1. additionwas added
  2. customSolvents were removed under reduced pressure
  3. customthe residue was partitioned between water and ethyl acetate
  4. customThe water layer was separated
  5. additionethyl acetate was added to it
  6. customThe organic phase was separated
  7. dry with materialdried (Na2SO4)
  8. concentrationconcentrated

Sources & evidence

ORD record
ord-d6692a118d48429bba350130e7d727f3
Source dataset
uspto-grants-2012_12
Patent number
US08329924B2

Reaction notes

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