Sodium Carbonate → Ethyl 3-methylthiophene-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

2-Bromo-3-methylthiophene (Lancaster, 26.4 g, 0.149 mol), Pd(OAc)2 (0.213 g, 0.95 mmol), 1,3-bis(diphenylphosphino) propane (0.49 g, 1.2 mmol), Na2CO3 (21.1 g, 0.20 mol), and 200 mL abs EtOH were placed into a 450 mL Hastalloy-C stirred pressure reactor, purged with N2, then pressurized with 490 psig CO, and the stirring reactor was heated to 120° C. for 36 hrs. Analysis of the reaction mixture by gas chromatography showed 1.3% and 96.9% area % starting bromomethylthiophene and carbonylation product, respectively. After cooling and venting, the reactor contents were filtered and evaporated to give a light yellow oil/solid mixture. This residue was extracted with 1,2-dichloroethane and water, and the organic phase was evaporated to give an oil. Filtration of this oil to remove residual salt gave 20.7 g (81% wt. % yield) of orange oil as ethyl 3-methyl-2-thiophenecarboxylate. 13C NMR {1H} CDCl3: δ162.8, 145.9, 131.7, 129.9, 127.0, 60.6, 15.9, 14.4 ppm.

Provenance & Evidence