Sodium Carbonate → 5-(2-Methoxy-3-nitro-phenyl)thiophene-2-carboxylic acid

Participants

Reaction Steps

2-(2-Methoxy-3-nitro-phenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane 6a (10 g, 35.85 mmol), 5-bromothiophene-2-carboxylic acid (6.68 g, 32.2 mmol), tetrakis(triphenylphosphine)palladium (2.07 g, 1.79 mmol) and sodium carbonate (7.59 g, 71.6 mmol) were dissolved in the solvent mixture of 200 mL of 1,4-dioxane and 30 mL of water. The reaction mixture was heated to reflux for 1 hour. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was filtered and the filtrate was concentrated under reduced pressure. The residue was diluted with 150 mL of water and adjusted to pH 3 with 1 N hydrochloric acid. The mixture was filtered and the filter cake was washed with 50 mL of the solvent mixture of n-hexane/ethyl acetate (V:V=1/1) and dried to obtain the title compound 5-(2-methoxy-3-nitro-phenyl)thiophene-2-carboxylic acid 12a (7.7 g, yield 77%) as a light yellow solid.

Provenance & Evidence