Methyl iodide → HCID 22031524, compound

Participants

Reaction Steps

66 mg potassium hydroxide (powder) was added to a mixture of 306 mg of 6-bromoimidazo[1,2-a]pyridine-3-carboxylic acid hydrazide (compound in Production Example 276), 195 mg carbon disulfide and 12 mL methanol under cooling with ice-water, and the mixture was stirred for 2.5 hours. Then, the reaction mixture was returned to room temperature, and 4 hours later, 75 μL methyl iodide was added thereto and stirred overnight. Ethyl acetate and water were added to the reaction solution, and the organic layer was separated, then washed with an aqueous saturated sodium bicarbonate solution and brine and dried over anhydrous sodium sulfate. The drying agent was filtered off, and the filtrate was evaporated. 243 mg crude product of methyl N′-(6-bromoimidazo[1,2-a]pyridine-3-carbonyl)hydrazine carbodithioate was obtained as pale yellow crystals. A mixture of this compound, 255 mg p-toluenesulfonic acid monohydrate and 15 mL toluene was heated for 1.5 hours under reflux. Ethyl acetate, tetrahydrofuran and water were added to the reaction solution which was then basified with sodium bicarbonate. The organic layer was separated, washed with brine and dried over anhydrous sodium sulfate. The drying agent was filtered off, and the filtrate was evaporated. The resulting residue was purified by NH silica gel column chromatography (ethyl acetate/hexane) to give 20 mg of the title compound as a white solid.

Provenance & Evidence