Methanol → 5-Oxo-4,5-dihydropyrazine-2-carbonitrile

Temperatur

5 °C

A stirred suspension of 5-carbamoylpyrazin-2-one (Chem. Pharm. Bull., 1980, 28, 3057; 0.28 g) in dry 1,4-dioxane (5 ml) was cooled to 5° C. prior to adding dry pyridine (0.65 ml). Trifluoroacetic anhydride (0.3 ml) was added dropwise and the reaction mixture allowed to warm to 10° C. After stirring at room temperature for 1 hour the reaction mixture became a slurry and additional trifluoroacetic anhydride (0.25 ml) and pyridine (0.5 ml) was added to give a brown solution. After an additional 1 hour at 10° C. the reaction mixture was added dropwise to methanol and the reaction mixture evaporated under reduced pressure to give a brown gum. The gum was treated with brine and extracted with ethylacetate. The organic phase was washed with dilute hydrochloric acid, brine and dried with sodium sulphate and evaporated under reduce pressure to give an oil that solidified upon scratching to give 5-cyanopyrazin-2-one as a brown solid.

1. temperatureto warm to 10° C
2. additionwas added
3. customto give a brown solution
4. customthe reaction mixture evaporated under reduced pressure
5. customto give a brown gum
6. extractionextracted with ethylacetate
7. washThe organic phase was washed with dilute hydrochloric acid, brine
8. dry with materialdried with sodium sulphate
9. customevaporated
10. customto give an oil that

ORD-Eintrag

ord-cd21b4cbd9f7415badf084cbf7209d42

Quelldatensatz

uspto-grants-1992_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05079251