Lawesson's reagent → Tert-butyl 8-chloro-3-phenyl[1,2,4]triazolo[4,3-a]pyridine-6-carboxylate

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Reaction Conditions

Reaction Steps

To a solution of tert-butyl 6-(2-benzoylhydrazino)-5-chloronicotinate (3.3 g, 9.49 mmol) in toluene (40 mL) was added Lawesson's reagent (1.92 g, 4.74 mmol). The mixture was stirred at 80° C. After 2 h, the mixture was concentrated. Saturated aqueous sodium bicarbonate was added and the mixture was extracted with ethyl acetate (3×). The combined organic layer was washed with brine, dried over sodium sulfate, filtered and concentrated. Purification by silica gel chromatography (100% dichloromethane→60% dichloromethane/ethyl acetate) gave the title compound (1.42 g): LC-MS [M+1]=330.1.

Provenance & Evidence