Nitromethane → Ethyl 2-thiopheneglyoxylate

Temperature

0 °C

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.

1. customReaction Scheme III
2. extractionThe resulting mixture is then extracted with an appropriate solvent such as diethyl ether
3. washThe organic layer is washed with saturated aqueous sodium bicarbonate
4. dry with materialdried over anhydrous sodium sulfate
5. concentrationconcentrated in vacuo
6. distillationThe residue is typically purified by either distillation or flash chromatography on silica gel

ORD record

ord-86882be3af7d4917abeb88fa8cf3baf0

Source dataset

uspto-grants-2003_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06613786B2