Dimethyl Carbonate → Methyl 3-methylthiophene-2-carboxylate

Participants

Reaction Steps

2-Bromo-3-methylthiophene (10.0 g, 0.0565 mol) was slowly added dropwise over a 60 minute period to a slurry of magnesium turnings (1.72 g, 0.0706) in THF. During the course of the addition, the exotherm was controlled to <40° C. by external cooling with a water bath. After the addition was completed, the resulting mixture was stirred at ambient temperature for 60 minutes. Dimethylcarbonate (7.63 g, 0.0847 mol) was then added dropwise over a 5-minute period, and the reaction mixture was stirred at ambient temperature for 4 hours. The reaction mixture was quenched by the addition of 6 M HCl (50 mL), and extracted with ethylacetate (100 mL). The organic phase was washed with water (25 mL), followed by saturated aqueous NaHCO3. Concentration of the organic phase then gave 7.38 g (84%) of methyl 3-methyl-2-thiophenecarboxylate as a light yellow oil.

Provenance & Evidence