6305-43-7

Report 1,

2,3-Butanedione (10 g; 116 mmol) and 20 mL CHCl3 were added to a 250 mL round-bottom flask equipped with a reflux condenser and a dropping funnel. Bromine (37 g, 12 mL, 232 mmol, d: 3.1028 g/mL) was dissolved in 25 mL CHCl3 and slowly added dropwise to the reaction mixture. The reaction was carried out at 50 °C until no HBr precipitated. The crude mixture was cooled overnight in a refrigerator. The precipitate was filtered off.

Report II

A solution of 2,3-butanedione (5.000 g, 58.0 mmol) in 10 mL of CHCl3 was slowly added dropwise to a solution of bromine (18.560 g, 116.0 mmol) in 6 mL of CHCl3 at room temperature. After the addition was complete, the reaction was carried out at 48 °C for 3 hours. The mixture was cooled in an ice bath for 2 hours, and the precipitate was filtered and purified by recrystallization from CHCl3 to obtain a yellow solid of 1,4-dibromo-2,3-butanedione. Yield: 9.112 g (65%). Melting point: 116-117 °C.

• Catalyst-Free Multicomponent Cyclopolymerizations: A novel approach utilizing 1,4-Dibromo-2,3-butanedione in catalyst-free multicomponent cyclopolymerizations to synthesize functional polyiminofurans containing bromomethyl groups was developed. This method enhances the utility of 1,4-Dibromo-2,3-butanedione in producing advanced materials with potential applications in chemical and pharmaceutical industries (Zhu et al., 2021).