Benzamide → N-Benzoyl-tetrahydro-3-oxo-1,1-diphenyl-3H-oxazolo[3,4-a]pyrazine-7(1H)-carboxamide

Temperature

90 °C

Benzamide (1.0 g, 8.3 mmol) was dissolved in 1,2-dichloroethane (5 mL), oxalyl dichloride (1.2 g, 9.1 mmol) was added thereto, and the mixture was stirred at 90° C. for 30 hours. The reaction solution was concentrated under reduced pressure. Toluene (4 mL) was added thereto and dissolved. Hexahydro-1,1-diphenyl-3H-oxazolo[3,4-a]pyrazin-3-one (0.20 g, 0.68 mmol) was added thereto, and the mixture was stirred at 60° C. for 6 hours. The reaction solution was concentrated under reduced pressure to a half its original volume, and the precipitated crystals were filtered off. The residue was purified with silica gel column chromatography (hexane:ethyl acetate=1:1), and toluene (4 mL) was added thereto. The precipitated crystals were filtered off, and the filtrate was concentrated. The residue was further purified with silica gel column chromatography (hexane:ethyl acetate=1:1) and crystallized from diisopropyl ether to obtain the title compound (70 mg, yield 23%).

1. concentrationThe reaction solution was concentrated under reduced pressure
2. additionToluene (4 mL) was added
3. dissolutiondissolved
4. stirringthe mixture was stirred at 60° C. for 6 hours
5. concentrationThe reaction solution was concentrated under reduced pressure to a half its original volume
6. filtrationthe precipitated crystals were filtered off
7. customThe residue was purified with silica gel column chromatography (hexane:ethyl acetate=1:1), and toluene (4 mL)
8. additionwas added
9. filtrationThe precipitated crystals were filtered off
10. concentrationthe filtrate was concentrated
11. customThe residue was further purified with silica gel column chromatography (hexane:ethyl acetate=1:1)
12. customcrystallized from diisopropyl ether

ORD record

ord-b16e9979b6494ab2a04385d37305622a

Source dataset

uspto-grants-2010_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07795267B2