| Uses | The Sonogashira cross-coupling reaction between 4-bromo-2, 1,3-benzothiadiazole, and the respective para-substituted phenylethynyl derivatives could synthesize the BTDs. In addition, the BTD-Ph is prepared by reacting 4-bromo-2,1,3-benzothiadiazole (Br-BTD)and palladium-MAI catalyst, and the dynamic phenylboronic acid reagent in the starting system or dynamic o-amino pyridine reagent[1-2]. |
| Synthesis | 273-13-2 22034-13-5 General procedure for the synthesis of 4-bromo-2,1,3-benzothiadiazole from 2,1,3-benzothiadiazole: In a round-bottomed flask equipped with a reflux condenser, 25.0 g (183.7 mmol) of 2,1,3-benzothiadiazole and 150 mL of 48% hydrobromic acid solution were added. After heating the mixture to 100 °C, 8.5 mL (165.4 mmol) of bromine was added slowly and the reaction was kept at 100 °C with stirring for 9 hours, followed by cooling to room temperature. Upon completion of the reaction, 200 mL of dichloromethane was added to the reaction mixture to dissolve the precipitated solid, followed by 100 mL of aqueous sodium sulfate. The organic layer was separated, washed with saturated aqueous sodium bicarbonate, dried over anhydrous sodium sulfate, and subsequently concentrated under reduced pressure to remove the solvent to afford the crude product 4-bromo-2,1,3-benzothiadiazole. The crude product was suspended in 200 mL of hexane/ethyl acetate (4:1, v/v) mixed solvent and filtered to remove the insoluble by-product 4,7-dibromo-2,1,3-benzothiadiazole. The filtrate was concentrated and suspended again in 200 mL of hexane and filtered to collect the solid to give 11.2 g of 4-bromo-2,1,3-benzothiadiazole. The filtrate was further concentrated and purified by column chromatography using hexane/ethyl acetate (97:3, v/v) as eluent to afford 8.0 g of 4-bromo-2,1,3-benzothiadiazole. A total of 19.2 g (89.3 mmol) of product was obtained in 49% yield. |
| References | [1] Pradhan, Asit Kumar et al. “Effects of donor and acceptor substituents on the photophysics of 4-ethynyl-2,1,3-benzothiadiazole derivatives?.” Physical Chemistry Chemical Physics 42 (2023): 29327–29340.
[2] AMARO DA SILVEIRA NETO B; CORREA J R; OLIVEIRA CARVALHO T; PIMENTA ROCHA CARVALHO P. "Selective cellular markers in selective cellular imaging of organelles such as mitochondria, nucleus and other organelles, are derived from 4-bromo-2,1,3-benzothiadiazole nucleus via homogeneous catalysis of palladium complex" BR102016025541(A2) |
