Methanol → Methyl pyrazinoate

Temperature

82.5 °C

20.0 g (805.8 mmole) of pyrazine-2-carboxylic acid was added to 160 mL of methanol, and 1.0 mL of a concentrated sulfuric acid was gradually dropwise added thereto with stirring. A reaction solution was refluxed at a temperature of 80 to 85° C. for 5 hours. The reaction solution was cooled to a temperature of 20 to 22° C. and concentrated to a volume of 25 mL. Then, 80 mL of methylenechloride and 40 mL of water were added to the resultant concentrate. The resultant solution was then neutralized by gradual addition of 40 mL of a saturated sodium hydrogen carbonate solution to get a pH of 8.5. An organic layer was separated and a water layer was extracted again with 40 mL of methylenechloride. The combined organic layer was dried over anhydrous magnesium sulfate, filtered, and washed with 20 mL of methylenechloride. A filtrate was concentrated to give 21.1 g of the titled compound as a pale brown solid (yield 94.8%).

1. additionwas gradually dropwise added
2. temperatureThe reaction solution was cooled to a temperature of 20 to 22° C.
3. concentrationconcentrated to a volume of 25 mL
4. additionThen, 80 mL of methylenechloride and 40 mL of water were added to the resultant
5. concentrationconcentrate
6. additionThe resultant solution was then neutralized by gradual addition of 40 mL of a saturated sodium hydrogen carbonate solution
7. customto get a pH of 8.5
8. customAn organic layer was separated
9. extractiona water layer was extracted again with 40 mL of methylenechloride
10. dry with materialThe combined organic layer was dried over anhydrous magnesium sulfate
11. filtrationfiltered
12. washwashed with 20 mL of methylenechloride
13. concentrationA filtrate was concentrated

ORD record

ord-3b46fb6ef7f8461a838fecbbfd3b1b9f

Source dataset

uspto-grants-2007_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07288652B2