Ethyl chloroformate → Ethyl 4-chloro-1H-pyrrolo[2,3-b]pyridine-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-chloro-1-(triisopropylsilyl)-1H-pyrrolo[2,3-b]-pyridine (15 g) in tetrahydrofuran (150 mL) was added 1M sec-butyllithium in tetrahydrofuran (97 mL) dropwise at −78° C. The mixture was stirred at −78° C. for 1 hour. To the mixture was added ethyl chloroformate (9.29 mL) and the mixture was stirred at −78° C. for 0.5 hour. The reaction mixture was quenched with saturated ammonium chloride aqueous solution and extracted with EtOAc. The extract was wash with water and brine, dried over MgSO4 and concentrated under reduced pressure. The residue was dissolved in tetrahydrofuran (120 mL) and to the solution was added 1M tetra-n-butylammonium fluoride in tetrahydrofuran (56 mL). The mixture was stirred at ambient temperature for 1 hour and then extracted with EtOAc. The extract was washed with water, dried over MgSO4 and concentrated under reduced pressure. The residue was with diisopropyl ether to give ethyl 4-chloro-1H-pyrrolo[2,3-b]pyridine-5-carboxylate.

Provenance & Evidence