Hydrochloric Acid → Methyl 3-chloro-5-methylthiophene-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of 3-Amino-5-methyl-thiophene-2-carboxylic acid methyl ester (5.0 g, 29.2 mmol) in 6N HCl (25 ml) was cooled to 0° C. (ice bath). A solution of sodium nitrite (2.01 g, 29.2 mmol) in water (5 ml) was added dropwise and the mixture was stirred at 0° C. for 60 min This mixture was then added to a solution of copper(I)chloride (2.89 g, 29.2 mmol) in conc. HCl (25 ml) at 0° C. The reaction mixture was stirred at room temperature then warmed to 65° C. until gas evolution had ceased. The reaction mixture was diluted with water and extracted with EtOAc (2×150 mL), washed with water, brine, dried over sodium sulfate, filtered and evaporated. The residue was purified by column (0-30% EtOAc in hexane) to give 4.4 g (79%) yellow oil product.

Provenance & Evidence