Ethyl chloroformate → HCID 58382073, compound

Participants

Reaction Steps

To a solution of 4-chloro-1-(triisopropylsilyl)-1H-pyrrolo[2,3-b]pyridine (3.03 g, 9.81 mmol, Adesis) in THF (49 mL) at about −78° C. was added sec-BuLi (1.4 M in cyclohexane, 15.4 mL, 21.6 mmol) dropwise. The reaction was stirred at about −78° C. for about 1 h before ethyl chloroformate (2.36 mL, 24.5 mmol) was added rapidly. The reaction mixture was allowed to warm to ambient temperature and was stirred for about 40 min. The reaction was quenched with saturated aqueous NH4Cl (25 mL). EtOAc (50 mL) and water (50 mL) were added and the layers were separated. The aqueous layer was extracted with EtOAc (2×20 mL) and the combined organic layers were washed with brine (2×20 mL). The organics were dried over anhydrous Na2SO4, filtered, and concd to dryness under reduced pressure to give a yellow oil. The oil was purified by silica gel chromatography eluting with a gradient of 0-10% EtOAc in heptane to give ethyl 4-chloro-1-(triisopropylsilyl)-1H-pyrrolo[2,3-b]pyridine-5-carboxylate (3.78 g, 98%) as a yellow oil: LC/MS (Table 1, Method b) Rt=3.98 min; MS m/z: 381 (M+H)+.

Provenance & Evidence