Nitromethane → Ethyl 2-thiopheneglyoxylate

Participants

Reaction Conditions

Reaction Steps

Reaction Scheme III shows the preparation of thiophenyl oxo-acetic acid derivatives IV, IVa and IVb from the corresponding appropriate thiophene derivatives VIII, VIIIa and VIIIb (equations 1-3, respectively). A mixture of an appropriate thiophene derivative such as VIII, VIIIa or VIIIb (1.0 equivalent) and ethyl oxalyl chloride (1.5 equivalents) may be treated with a solution of aluminum trichloride in nitromethane (1.5 equivalents, concentration approximately 3.6 M) at a temperature of approximately 0-10° C. The reaction mixture is stirred at approximately 0° C. for one hour, room temperature for three hours and then poured into ice water. The resulting mixture is then extracted with an appropriate solvent such as diethyl ether. The organic layer is washed with saturated aqueous sodium bicarbonate, dried over anhydrous sodium sulfate and concentrated in vacuo. The residue is typically purified by either distillation or flash chromatography on silica gel to provide the thiophenyl oxo-acetic acid ethyl ester VII, VIIa or VIIb, respectively.

Provenance & Evidence