Sodium Hydroxide → 5-Oxazol-4-yl-thiophene-3-carboxylic acid

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Reaction Steps

5-Oxazol-4-yl-thiophene-3-carboxylic acid methyl ester (0.338 g, 1.62 mmol) was dissolved in methanol (3 mL) and sodium hydroxide (1 N, 2.1 mL) was added. The mixture was stirred at room temperature for 2 hours then a further amount of sodium hydroxide (1 N, 1 mL) was added and stirring continued overnight. The mixture was concentrated and the residue treated with HCl (1 N, 3.5 mL). The resultant precipitate was collected by filtration to give the title compound as a tan/off-white solid (0.158 g). The filtrate was passed through an SCX-2 cartridge (20 g) and concentrated to give a further amount of the title compound as a tan solid (0.078 g). LCMS m/z 196.13 [M+H]+ R. T.=3.22 min (Analytical Method 9).

Provenance & Evidence