Sodium Hydroxide → 4-Chloro-2-methylthiophene-3-carboxylic acid

Participants

Reaction Steps

A mixture of ethyl 4-chloro-2-methylthiophene-3-carboxylate (F-6) (4.98 g, 24.3 mmol, 1.0 eq) in EtOH (50 mL) ar RT, aqueous NaOH solution (20%, 14.6 g, 73.0 mmol, 3.0 eq) is added and the resulting mixture is stirred at reflux for 1 h. The mixture is allowed to cool to RT and concentrated in vacuo. The residue is poured into ice water (30 mL) and neutralized with concentrated HCl to adjust the pH to 1-2 while keeping the temperature below 5° C. The precipitate is collected by filtration, rinsed with H2O (80 mL) and dried in vacuo to afford the product, 4-chloro-2-methylthiophene-3-carboxylic acid (F-7).

Provenance & Evidence