Oxalyl chloride → HCID 21947709, compound

Participants

Reaction Steps

A solution of 4-(2,5-dimethyl-1H-pyrrol-1-yl)-3,5-dimethylbenzoic acid of Step B (0.495 g, 2 mmol) was dissolved in tetrahydrofuran (10 mL) and treated with N,N-dimethylformamide (10 μL) followed by oxalyl chloride (250 μL, 2.85 mmol) added dropwise to control gas evolution. When the gas evolution subsided, the solution was warmed to reflux for 5 minutes. The solution was then concentrated in vacuo, the residue was dissolved in tetrahydrofuran and evaporated to dryness. The residue was redissolved in dichloromethane and the solution added dropwise to a cold solution (0° C.) of 10,11-dihydro-5H-pyrrolo[2,1-c][1,4]benzodiazepine (0.372mg, 2 mmol) and Hünig's base (0.5 mL) in dichloromethane. The solution was stirred overnight at room temperature, washed successively with 1N hydrochloric acid, saturated aqueous bicarbonate, and brine. The sample was then dried over anhydrous sodium sulfate, filtered and evaporated in vacuo to a yellow foam (0.75 g). Flash chromatography of this material on silica gel eluting with a solvent gradient of 10 to 20% of ethyl acetate in hexane, provided a white solid (0.130 g). Recrystallization of this material from ethyl acetate/hexane provided the title compound (0.120 g) as flat crystals, m.p. 197–199° C.

Provenance & Evidence