Abstract An unequivocal two step synthesis of 2-amino-3-cyano-5-formylpyrazine diethylacetal, starting from dimethylaminoacrolein and O-tosylisonitrosomalononitrile, is described. This pyrazine is a key intermediate for the preparation of folic acid and various analogues.
![[[[(4-methylphenyl)sulphonyl]oxy]imino]malononitrile结构式](https://image.chemsrc.com/caspic/197/20893-01-0.png)
