Succinic anhydride → Tetrahydro-gamma,3-dioxo-1,1-diphenyl-3H-oxazolo[3,4-a]pyrazine-7(1H)-butanoic acid

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Reaction Steps

To a solution of hexahydro-1,1-diphenyl-3H-oxazolo[3,4-a]pyrazin-3-one (0.15 g, 0.50 mmol) in tetrahydrofuran (10 mL) were added triethylamine (0.14 mL, 1.0 mmol) and succinic anhydride (55 mg, 0.55 mmol), and the mixture was stirred at room temperature for 2 hours. To the reaction solution was added ethyl acetate, and the resulting mixture was washed with 2 M hydrochloric acid, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified with silica gel column chromatography (hexane:ethyl acetate=1:1 to ethyl acetate). The fractions were concentrated, and to the residue was added diethyl ether. The resulting crystals were collected by filtration and washed with diethyl ether to obtain the title compound (99 mg, yield 50%).

Provenance & Evidence