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-6-yl)phenyl)cyclobutyl)carbamate (211 mg, 0.45 mmol) in toluene (15 mL) was added lawesson's reagent (181 mg, 0.45 mmol) under nitrogen. The resulting mixture was heated under reflux for 2 h. After cooled down to room temperature, the mixture was concentrated to dryness under reduced pressure. The resulting residue was purified by Biotage silica gel chromatography (gradient 0 to 5% MeOH in dichloromethane) to give the title compound as a yellow solid (124 mg, 57%). 1H NMR (500 MHz, CDCl3): 9.47 (1H, br s), 7.30-7.24 (7H, m), 7.18 (1H, s), 7.16-7.14 (2H, m), 5.17 (2H, s), 5.04 (1H, br s), 2.55-2.25 (4H, m), 2.10-2.01 (1H, m), 1.85-1.76 (1H, m), 1.44-1.15 (9H, br).

Provenance & Evidence