[C:1](Cl)(=O)[C:2]([Cl:4])=[O:3].[CH3:7][N:8]([CH2:10][CH2:11][CH2:12][CH2:13]CC(O)=O)[CH3:9].C(=O)=O>>[ClH:4].[CH3:7][N:8]([CH2:10][CH2:11][CH2:12][CH2:13][CH2:1][C:2]([Cl:4])=[O:3])[CH3:9]Into a 500 ml three-necked round-bottomed flask equipped with a reflux condenser, internal thermometer, mechanical stirrer, and argon inlet, is placed oxalyl chloride (398.67 g, 3.14 mol). Acid 2 (100 g, 0.63 mol) is added over 30 min while maintaining the reaction temperature at 40° C. As reaction takes place, CO2 and CO are swept away from the mixture with argon. After addition is complete, the mixture is stirred for 2 h while the reaction flask cools to room temperature. Excess oxalyl chloride is removed by rotary evaporation at 50° C. and then by Kugelrohr distillation at 50° C. (0.1 mm Hg) for 2 h. Isolated is 3, 118.98 g (88.5%) as an oil that solidifies on standing.
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