Potassium Hydroxide → 2-Thiophenecarboxylic acid, 4-bromo-3-methoxy-

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Reaction Steps

A solution of 37.5 g (0.15 mole) of methyl 4-bromo-3-methoxy-2-thiophenecarboxylate and 12 g of KOH (0.18 mole) in a mixture of 250 mL of methanol and 100 mL of water was refluxed for 2 hr. The reaction mixture was cooled and most of the methanol was removed in vacuo. The solution was partitioned with ether and dilute aqueous HCl. The organic phase was separated dried over MgSO4, filtered and concentrated and dried under a vacuum to give 34 g (94%) of a colorless solid. mp 191-192° C. 1H NMR (300 MHz, CDCl3): δ 7.5 (s, 1H); 4.1 (s, 3H). Anal. Calc'd for C6H5BrO3S: C, 30.04; H, 2.23; S, 13.52. Found: C, 29.89; H, 2.06; S, 13.14.

Provenance & Evidence