[CH3:1][C:2]1[CH:9]=[CH:8][C:5]([C:6]#[N:7])=[CH:4][C:3]=1[N+:10]([O-:12])=[O:11].[CH2:13]([O:16][C:17](=[O:23])[C:18](OCC)=[O:19])[CH2:14]C.CC[O-].[Na+].Cl>CCO>[CH2:13]([O:16][C:17](=[O:23])[C:18](=[O:19])[CH2:1][C:2]1[CH:9]=[CH:8][C:5]([C:6]#[N:7])=[CH:4][C:3]=1[N+:10]([O-:12])=[O:11])[CH3:14]Treat a suspension of 4-methyl-3-nitro-benzonitrile (2.11 g, 12.5 mmol) and oxalic acid ethyl ester propyl ester (2.99 g, 18.7 mmol) in EtOH (80 mL) with NaOEt (21% w/w, 18.2 mL). Stir the mixture at 40° C. overnight. Quench the reaction with water and acidify with 1 M HCl solution. Concentrate to a residue and partition between EtOAc and water. Concentrate the organic layer and purify by silica gel chromatography to give the desired product 3-(4-cyano-2-nitro-phenyl)-2-oxo-propionic acid ethyl ester (3:1 keto/enol mixture) as a solid in 37% yield (1.21 g, 4.62 mmol).
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