174508-31-7

Needle-like solid

5,7-Dibromo-2,3-dihydrothieno[3,4-b]-1,4-dioxine is used in the preparation of 3,4-ethylenedioxythiophene oligomers with optical and redox properties.

The general procedure for the synthesis of 2,5-dibromo-3,4-ethenyldioxythiophene from 3,4-ethenyldioxythiophene was as follows: a solution of tetrahydrofuran (THF, 20 mL) with 3,4-ethenyldioxythiophene (1.42 g, 10.60 mmol), N-bromosuccinimide (3.74 g, 12.80 mmol), and acetic acid (20 mL) was added sequentially to a round bottomed flask. The reaction mixture was stirred at room temperature for 2 hours. Upon completion of the reaction, the mixture was poured into distilled water and stirred with a glass rod to promote the formation of the precipitate. Subsequently, the precipitate was collected by filtration to afford the target product 2,5-dibromo-3,4-vinyl dioxythiophene (A4) as a white solid (2.50 g, 8.30 mmol, 83% yield). The product was characterized by 1H NMR (400 MHz, CDCl3) with chemical shift δ = 4.27 (s, 4H).

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