Diethyl Succinate (42 mmol, 1 eq, 7.32 g) was added dropwise while the mixture was still at 120 °C, the mixture became dark red in color upon the addition of the diethyl succinate. The reaction was carried overnight at 120 °C. The reaction mixture was cooled down to room temperature and 10 ml of acetic acid were used to neutralize the excess of base. The reaction mixture turned dark purple. The purification was performed by filtering the mixture through a P16 fritted glass filter funnel and the solid product was put in the oven to dry overnight. Compound 4 was obtained as a purple solid. Yield: 14.24 g, 72%.