Hydrochloric Acid → Ethyl 3-methylthieno[3,2-b]pyridine-2-carboxylate

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Reaction Steps

To a solution (100 mL) of 3-chloropyridine-2-carbonitrile (10.0 g) in tetrahydrofuran was added a 3.0M solution (48.0 mL) of methylmagnesium bromide in diethyl ether, and the mixture was stirred at room temperature for 3 hr. To the reaction mixture was added 2N hydrochloric acid (300 mL), tetrahydrofuran was evaporated in an evaporator, and the residue was extracted with ethyl acetate. The extract was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (30-70% ethyl acetate/hexane) to give a pale-yellow oil. To a mixture of the obtained oil, ethyl mercaptoacetate (4.23 mL) and N,N-dimethylformmide (60 mL) was added and potassium carbonate (16.0 g), and the mixture was stirred overnight at 50° C. Water was added to quench the reaction, and the precipitated solid was collected by filtration to give the title object compound (6.75 g, 79%) as a white solid.

Provenance & Evidence