Synthesis
The general procedure for the synthesis of 5-aminopyrazine-2-carbonitrile from 2-amino-5-bromopyrazine and potassium cyanide is as follows:
1. tetrakis(triphenylphosphine)palladium(0) (10 mg), 5-bromopyrazin-2-amine (0.575 mmol), potassium cyanide (1.15 mmol), copper(I) iodide (0.575 mmol), and 18-crown-6 (20 mg) were sequentially added to a screw-capped reaction vessel under nitrogen protection.
2. Anhydrous DMF (1 mL) was added to the reaction mixture and the mixture was heated to 200 °C with stirring for 1 hour.
3. Upon completion of the reaction, the mixture was cooled to room temperature and quenched by the addition of water (5 mL).
4. The product in the reaction mixture was extracted with chloroform (2 x 5 mL).
5. The organic phases were combined and purified by silica gel column chromatography (eluent: hexane/ethyl acetate) to afford the target compound 5-aminopyrazine-2-carbonitrile (0.208 mmol, 36% yield).
References
[1] Patent: US2004/34038, 2004, A1. Location in patent: Page/Page column 10
[2] Journal of Heterocyclic Chemistry, 1987, vol. 24, p. 1371 - 1372
[3] Patent: US2007/37820, 2007, A1. Location in patent: Page/Page column 14-15
[4] Patent: WO2006/105262, 2006, A1. Location in patent: Page/Page column 77
