反应详情

温度

0 °C

Into a one-litre flask equipped with a mechanical stirrer and a dropping-funnel were introduced 39 g (0.97 mol) of sodium hydroxide with 270 ml of water. The solution was cooled to 0° C by means of an ice-bath and 20 ml (0.333 mol) of bromine were then added through the dropping-funnel followed by 190 ml of dioxan, care being taken to maintain the temperature at 0° C. Finally, still at the same temperature, a solution of 22.6 g (0.111 mol) of 2-ethyl-3-acetyl-benzo[b]thiophene in 25 ml of dioxan were introduced drop-by-drop. The mixture was then allowed to return to room temperature and stirring was maintained for 2 hours. A solution of sodium bisulphite was then added and the reaction medium was acidified and extracted with ether. The organic phase was washed with water, dried and evaporated to dryness to give 20.2 g of 2-ethyl-3-carboxy-benzo[b]thiophene. Yield 92%; M.P. 136° C.

1. customInto a one-litre flask equipped with a mechanical stirrer and a dropping-funnel
2. temperatureto maintain the temperature at 0° C
3. customto return to room temperature
4. temperaturewas maintained for 2 hours
5. extractionextracted with ether
6. washThe organic phase was washed with water
7. customdried
8. customevaporated to dryness