[H-].[Na+].[C:3]([O:10][CH3:11])(=[O:9])[CH2:4][C:5]([O:7][CH3:8])=[O:6].Cl[C:13]1[CH:18]=[CH:17][C:16]([N+:19]([O-:21])=[O:20])=[CH:15][C:14]=1[Cl:22]>CN(C=O)C>[Cl:22][C:14]1[CH:15]=[C:16]([N+:19]([O-:21])=[O:20])[CH:17]=[CH:18][C:13]=1[CH:4]([C:3]([O:10][CH3:11])=[O:9])[C:5]([O:7][CH3:8])=[O:6]NaH (288 mmol) was suspended in DMF (370 mL) at 0° C. under an atmosphere of nitrogen. Dimethyl malonate (261 mmol) in DMF (30 mL) was added dropwise over a period of 20 min. at 0° C. and stirring was continued at 0° C. for 30 min. Then 1,2-dichloro-4-nitrobenzene (130 mmol) in DMF (35 mL) was added dropwise at 0° C. over a period of 20 min. The mixture was stirred at 70° C. for 15 h. The reaction mixture was cooled to room temperature and quenched with NH4Cl. The solution was successively washed with EtOAc (1×100 mL, 1×250 mL) and water (2×150 mL). To facilitate separation of the layers, sat. aq. NaCl (20 mL) was added. The organic layer was separated and washed with sat. aq. NaCl (2×100 mL). The aqueous layer was backextracted with EtOAc (2×50 mL). The organic layer was dried over Na2SO4, filtered and concentrated under reduced pressure. The crude material was recrystallized from EtOH to give dimethyl 2-(2-chloro-4-nitrophenyl)malonate as a solid (74%).
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