Ammonia → Methyl 5-aminopyrazine-2-carboxylate

Temperature

0 °C

A large steel reaction vessel was charged with a solution of 5-fluoro-pyrazine-2-carboxylic acid methyl ester (17.45 g, 111.78 mmol) in tetrahydrofuran (200 mL). The reaction solution was cooled to 0° C. and was saturated with ammonia gas over 2–3 h. The vessel was then tightly sealed. The reaction was then mechanically agitated and allowed to warm to 25° C. overnight. The vessel was then cooled to −78° C. for 15–20 min, the vessel was carefully vented, and the contents of the vessel were diluted with diethyl ether (100 mL). The resulting precipitate was isolated via filtration, rinsed with petroleum ether (2×100 mL), and air-dried to afford 5-amino-pyrazine-2-carboxylic acid methyl ester (16.97 g, 99%) as an off-white solid: mp 229–231° C.; EI-HRMS m/e calcd for C6H7N3O2 (M+) 153.0538, found 153.0537.

1. customThe vessel was then tightly sealed
2. temperatureto warm to 25° C. overnight
3. temperatureThe vessel was then cooled to −78° C. for 15–20 min
4. customThe resulting precipitate was isolated via filtration
5. washrinsed with petroleum ether (2×100 mL)
6. customair-dried

ORD record

ord-743e20d23af947e39078d96920753137

Source dataset

uspto-grants-2006_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07132425B2