Toluene → HCID 22032300, compound

Participants

Reaction Steps

0.22 mL cyclopropane carbonyl chloride was added at room temperature to a mixture of 510 mg 6-bromoimidazo[1,2-a]pyridine-3-carboxylic acid hydrazide (compound in Production Example 276), 202 mg sodium bicarbonate, 15 mL tetrahydrofuran and 15 mL water, and the mixture was stirred overnight. The organic layer was separated by adding saturated sodium bicarbonate, common salt and tetrahydrofuran to the reaction solution. The aqueous layer was further extracted with tetrahydrofuran, and the combined organic layer was washed with brine and then dried over anhydrous sodium sulfate. The drying agent was filtered off, and the filtrate was evaporated. Diisopropyl ether was added to the resulting residues, and the formed crystals were collected by filtration and dried under reduced pressure by a vacuum pump. 606 mg crude product of cyclopropane carboxylic acid N′-(6-bromoimidazo[1,2-a]-pyridine-3-carbonyl)hydrazide was obtained as pale brown crystals. A mixture of 200 mg of this carboxylic acid hydrazide derivative, 250 mg Lawesson's reagent and 20 mL anhydrous toluene was heated for 1 hour under reflux. The reaction solution was evaporated, and the resulting residue was purified by NH silica gel column chromatography (ethyl acetate/hexane) to give 48 mg of the title compound as a white solid.

Provenance & Evidence