Hydrochloric Acid → Ethyl 1-(benzenesulfonyl)-5-chloro-1H-pyrrolo[3,2-b]pyridine-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

1.6 M n-Butyllithium in hexanes (9.6 mL, 15 mmol) was added dropwise to a solution of N,N-diisopropylamine (2.3 mL, 16 mmol) in THF (43 mL) at −78° C. Following complete addition, the temperature of the reaction was raised to 0° C. for 30 minutes and then was re-cooled to −78° C. 5-Chloro-1-(phenylsulfonyl)-1H-pyrrolo[3,2-b]pyridine (3.00 g, 10.2 mmol, from Example 2, Step 1) in THF (8 mL) was added dropwise and the reaction was stirred for 1 hour, at which time ethyl chloroformate (1.4 mL, 14 mmol, Alfa Aesar) was added. The reaction was allowed to stir at −78° C. for 2 hours and was then allowed to warm to room temperature. The mixture was poured into dilute HCl and extracted with three portions of ethyl acetate. The combined extracts were dried over sodium sulfate, decanted, and the solvent was removed in vacuo. Flash chromatography eluting with a gradient from 0-50% EtOAc in hexanes afforded product as an off white solid (1.8 g, 48%).

Provenance & Evidence