Oxalyl chloride

BrCH₂CH₂NH₃⁺Br^- (2.0 g, 10 mmol, Aladdin Chemistry Co., Ltd.) and TPP (2.6 g, 10 mmol, Energy Chemical Co., Ltd. China) were refluxed in acetonitrile (40 mL, Sinopharm Chemical Reagent Co., Ltd.) with stirring for 24 h. The reaction mixture was allowed to evaporate by rotation and the remaining crystals were dissolved in a small amount of water and the aqueous solution was adjusted to pH 11.0 with NaOH (2 mol L⁻¹, Sinopharm Chemical Reagent Co., Ltd.). After that, the water was evaporated by rotation and extracted with methanol to get TPP-NH_2. Lonidamine (LND, 0.4 g, 1.1 mmol, Aladdin Chemistry Co., Ltd.), oxalyl chloride (2 mL, Sinopharm Chemical Reagent Co., Ltd.) and N, N-dimethylformamide (DMF, 0.1 mL, Sinopharm Chemical Reagent Co., Ltd.) were added to dichloromethane (20 mL) and refluxed at 50 °C for 2 h. The yellow solid was obtained by spin evaporation under reduced pressure. Then TPP-NH₂ (0.5 g, 1.1 mmol), triethylamine (160 μL, 1.1 mmol) and the above yellow solid were dissolved in dichloromethane (20 mL), stirred at room temperature for 12 h and extracted by ultrapure water. The organic phase was dried with anhydrous Na₂SO₄ (Sinopharm Chemical Reagent Co., Ltd.) and left to stand overnight. The liquid was finally collected and the solvent was removed by rotary evaporation and dried under vacuum to give a yellow-brown solid as TLND.