Butanedione → 5,6-dimethylpyrazine-2-carboxylic Acid

To a solution of 2,3-diaminopropanoic acid hydrochloride (1 g, 7.11 mmol) in methanol (63 mL) was added sodium hydroxide (1.42 g, 28.4 mmol) at 10° C., and then the mixture was degassed with N2. After 30 min, biacetyl (612 mg, 7.11 mmol) was added and the reaction mixture was stirred at the same temperature for 3 h. Dry air was passed through the reaction mixture for 16 h. The solvent was then removed under reduced pressure, the residue was dissolved in water (7 mL), and the solution was adjusted to pH 2 with concentrated HCl slowly at 0° C., and the mixture was filtered. The yellow solid (580 mg) was used in the next step without further purification. MS (ESI): m/z 153.1 [M+H]+.

1. customthe mixture was degassed with N2
2. customDry air
3. waitwas passed through the reaction mixture for 16 h
4. customThe solvent was then removed under reduced pressure
5. dissolutionthe residue was dissolved in water (7 mL)
6. customwas adjusted to pH 2 with concentrated HCl slowly at 0° C.
7. filtrationthe mixture was filtered
8. customThe yellow solid (580 mg) was used in the next step without further purification

ORD record

ord-8ba5e51e318d4dc7b408d9ebae7e7565

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08969349B2