Ethyl chloroformate → ethyl 4-chloro-2-methyl-1-(triisopropylsilyl)-1H-pyrrolo[2,3-b]pyridine-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of 4-chloro-2-methyl-1-(triisopropylsilyl)-1H-pyrrolo[2,3-b]pyridine (525 mg) in tetrahydrofuran (10 ml) was cooled to −78° C. under nitrogen atmosphere, and to the reaction mixture was added 0.99M sec-butyllithium/cyclohexane solution (4.1 ml) dropwise. After the mixture was stirred at −78° C., ethyl chlorocarbonate (389 μl) was added dropwise. The reaction solution was stirred at −78° C. for 30 minutes, saturated aqueous ammonium chloride (20 ml) was added, and the temperature was returned to ambient temperature. The reaction solution was transferred into a separating funnel and extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous magnesium sulfate, filtered, and evaporated under reduced pressure. The residue was purified by silica gel column chromatography (n-hexane) to obtain ethyl 4-chloro-2-methyl-1-(triisopropylsilyl)-1H-pyrrolo[2,3-b]pyridine-5-carboxylate (645 mg) as a colorless viscous liquid.

Provenance & Evidence