Lithium Hydroxide → 3-[Tert-butyl-(2,4-dichlorobenzoyl)amino]-5-phenyl-thiophene-2-carboxylic acid

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Reaction Steps

3-[tert-Butyl-(2,4-dichloro-benzoyl)-amino]-5-phenyl-thiophene-2-carboxylic acid methyl ester (112 mg, 0.24 mmol) was dissolved in a mixture of THF-MeOH—H2O (3:2:1) (15 mL) and then 1.5 ml of LiOH 1N was added to it. After 3 h of stirring at room temperature, solvent was removed and then partitioned between 15 ml of H2O, 4 ml of KHSO4 5% and 15 ml of EtOAc. The organic layer was separated and the aqueous phase was washed twice with ethyl acetate (2×10 mL). The combined ethyl acetate layer was dried (MgSO4), concentrated and the residue was purified by preparative chromatography (10% MeOH/CH2Cl2) to obtain 32 mg (29%) of 3-[tert-Butyl-(2,4-dichloro-benzoyl)-amino]-5-phenyl-thiophene-2-carboxylic acid. NMR 1H (DMSO, 400 MHz): 7.62 ppm (d, 2H, Haro); 7.44-7.34 ppm (m, 4H, Haro); 7.32-7.12 ppm (m, 3H, Haro); 2.48 ppm (s, 9H).

Provenance & Evidence