2-Pyrazinecarboxylic acid → Pyrazinecarbonyl chloride

Participants

Reaction Conditions

Reaction Steps

To a solution of pyrazine-2-carboxylic acid (1.36 g, 10.9 mmol, 1 eq.) in SOCl2 (20 mL) was added DMF (2 drops). The mixture was stirred at 60° C. for 2.0 min. The volatiles were removed in vacuo to give crude pyrazine-2-carbonyl chloride, which was used in the next step directly. TO a suspension of 2-amino-5-nitrobenzoic acid (2.00 g, 10.9 mmol, 1.0 eq.) in THF (50 mL) was added Et3N (1.09 g) and pyrazine-2-carbonyl chloride in anhydrous THF (50 mL) dropwise. The resulting mixture was stirred at room temperature for 18 h. After the reaction was completed, the volatiles were removed. The residue was suspended in H2O (10 mL) and the pH was adjusted to 5 by slow addition of 2N HCl in water. The resulting solid was collected and dried in vacuo to give 3.12 g of 5-nitro-2-(pyrazine-2-carboxamido)benzoic acid as a brown solid (99%). LCMS m/z=289.0 (M+1) (Method B) (retention time=1.24 min),

Provenance & Evidence