Dimethyl Carbonate → Methyl 3-methylthiophene-2-carboxylate

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.

1. additionDuring the course of the addition
2. customwas controlled to <40° C.
3. temperatureby external cooling with a water bath
4. additionAfter the addition
5. stirringthe reaction mixture was stirred at ambient temperature for 4 hours
6. customThe reaction mixture was quenched by the addition of 6 M HCl (50 mL)
7. extractionextracted with ethylacetate (100 mL)
8. washThe organic phase was washed with water (25 mL)

ORD record

ord-1dc9237404b0439b8d776c723514b7c7

Source dataset

uspto-grants-2001_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06265424B1