Yield:72111-57-0 77%

Reaction Conditions:

with pyridine in thionyl chloride;water;

Steps:

3 Preparation of 2,3-dicyano-5-chloropyrazine

EXAMPLE 3 Preparation of 2,3-dicyano-5-chloropyrazine 2,3-Dicyano-5-hydroxypyrazine (7.30 g; 0.05 mole) was dissolved in 70 g (0.59 mole) of thionyl chloride, and the solution was cooled to 0° to 5° C. With stirring, 4.80 g (0.06 mole) of pyridine was added dropwise over the period of 15 minutes. Then, the mixture was stirred at 70° C. for 2 hours. After the reaction, the excess of thionyl chloride was distilled off under reduced pressure, and the residue was extracted with 150 ml of chloroform. The chloroform solution was washed twice with 50 ml of water, and dried over anhydrous calcium chloride, and then the solvent was distilled off to afford a red solid. Recrystallization of the solid from benzene afforded 6.30 g (yield 77%) of 2,3-dicyano-5-chloropyrazine. Melting point: 89°-90° C. Elemental analysis for C₆ HN₄ Cl: Calcd. C 43.79, H 0.61, N 34.05; Found C 43.75, H 0.61, N 34.13. IR (KBr) cm^-1 ν_{C N} 2230.

References:

US4259489,1981,A