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 to a solution of N,N-diisopropylamine (2.3 mL, 16 mmol) in THF (43 mL) at −78° C. Upon complete addition, the reaction was warmed to 0° C. for 30 minutes and then was re-cooled to −78° C. A solution of 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. After stirring for one hour at −78° C., ethyl chloroformate (1.4 mL, 14 mmol, Alfa Aesar) was added and the reaction was stirred at −78° C. for 2 hours, after which time it was allowed to warm to room temperature. The reaction was poured into dilute HCl and the product was extracted with three portions of ethyl acetate. The combined extracts were dried over sodium sulfate, decanted, and the solvent removed in vacuo. Flash chromatography, eluting with a gradient from 0-30% EtOAc in hexanes afforded product as a yellow solid (2.15 g, 57%).

Provenance & Evidence