Lawesson's reagent → Tert-butyl (1-(4-(7-phenyl-2-thioxo-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazin-6-yl)phenyl)cyclobutyl)carbamate

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Reaction Steps

To a solution of tert-butyl(1-(4-(2-oxo-7-phenyl-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazin-6yl)phenyl)cyclobutyl)carbamate (5 g, 10.60 mmol) in toluene (380 ml) was added Lawesson's reagent (4.29 g, 10.60 mmol). The resulting mixture was heated under reflux for 5 hours. After it was cooled down to room temperature, the mixture was concentrated to dryness under reduced pressure. The resulting residue was dissolved in the minimum amount of dichloromethane (500 ml) and treated with diisopropyl ether (800 ml). A yellow solid crushed out. It was filtered and dried until constant weight (4.7 g, 91%). LCMS (Method D): RT=1.526 min, M+1=488.

Provenance & Evidence