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off-white powder

6-Bromobenzo[b]thiophene is a reagent for the synthesis of aminobenzo[b]thiophene 1,1-dioxides as STAT3 inhibitors with antitumor activities being an attractive therapeutic target for cancer therapy.

Part C. Preparation of 6-bromobenzo[b]thiophene. 6-Bromobenzo[b]thiophene-2-carboxylic acid (0.70 g, 2.73 mmol) from Part B was mixed with DBU (1.35 mL, 8.94 mmol) in DMA (6 mL) in a sealed tube and heated in a microwave reactor for 70 min at 200 °C. After completion of the reaction, the resulting dark solution was diluted with 1 M HCl (20 mL) and extracted with dichloromethane (2 x 20 mL). The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using dichloromethane as eluent to afford 6-bromobenzo[b]thiophene as an oil (0.484 g, 83% yield).

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