Lawesson's reagent → 5-Bromo-2-(3-propylureido)pyridine-4-carbothioamide

Participants

Reaction Conditions

Reaction Steps

A suspended mixture of 5-bromo-2-(3-propylureido)isonicotinamide (Intermediate 43, 123 g, 407 mmol), Lawesson's Reagent (131.6 g, 326 mmol), and tetrahydrofuran (1.55 L) was stirred at 70° C. for 18 h. Stirring was stopped and a bright yellow precipitate was allowed to settle. The precipitate was then vacuum filtered and washed with methyl tert-butyl ether (2×500 L). This solid was then dried in the vacuum oven at 50° C. for 12 hours to give 50 g of product solid. The mother liquor was concentrated and the residue was suspended in toluene (300 mL). The solid thus obtained was filtered and combined with the previous solid. The combined totaled 110 g (85%) of 5-bromo-2-(3-propylureido)pyridine -4-carbothioamide as an off white solid

Provenance & Evidence