Methyl iodide → 1-(Phensulfonyl)-5-chloro-2-methyl-1H-pyrrolo[3,2-B]pyridine

Participants

Reaction Conditions

Reaction Steps

To N,N-diisopropylamine (13 mL, 93 mmol, Aldrich) in tetrahydrofuran (200 mL) at −78° C. was added 1.6 M n-butyllithium in hexanes (55 mL, 88 mmol, Aldrich). The reaction mixture was warmed to 0° C., and the mixture was stirred for 30 minutes. The reaction mixture was cooled to −78° C., and 5-chloro-1-(phenylsulfonyl)-1H-pyrrolo[3,2-b]pyridine (17.1 g, 58.4 mmol, from Step 1) in tetrahydrofuran (86 mL) was added dropwise over 30 minutes. The reaction mixture was then stirred for 1 hour at −78° C., and methyl iodide (7.3 mL, 120 mmol, Aldrich) was added dropwise over 5 minutes. The reaction was allowed to warm to 5° C. over 3 hours, then cooled to −20° C. and quenched by the addition of 1 N HCl. EtOAc was added, and the solution was stirred for 15 minutes and left at ambient temperature overnight. The layers were separated and the organic layer was washed sequentially with water and brine, dried over sodium sulfate, filtered and concentrated in vacuo to give a wet orange solid that was then triturated with MeOH (18 mL). The solid was isolated by filtration, washed and dried at 40° C. under high vacuum for 2.2 h to give 14.4 g of product. Additional amount of product was obtained by flash chromatography of the filtrate (eluting with a gradient from 0-40% EtOAc in hexanes) afforded 1.87 g. (Yield: 16.3 g, 91%).

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