2,3-pyrazinedicarboxylic acid, diethyl ester InChI=1/C10H12N2O4/c1-3-15-9(13)7-8(10(14)16-4-2)12-6-5-11-7/h5-6H,3-4H2,1-2H diethyl pyrazine-2,3-dicarboxylate