Boron tribromide → 2,6-Dibromo-benzo[1,2-b:4,5-b']dithiophene-4,8-diol

Temperature

-78 °C

2,6-Dibromo-4,8-dimethoxy-benzo[1,2-b:4,5-b′]dithiophene (500 mg, 1.22 mmol., 1.00 equiv.) and dichloromethane (12 mL) were added to a 50 mL schlenk flask. The mixture was cooled to −78 ° C. and boron tribromide was added (1.0 M solution in dichloromethane, 2.5 mL, 2.5 mmol., 2.1 equiv.) slowly. The mixture was stirred for 15 minutes at −78° C. before replacing the dry/ice acetone bath with an ice/water bath. The reaction mixture was left to warm to room temperature while stirring for 16 hours before cooling to 0° C. Water (dropwise at first, 150 mL total) and additional dichloromethane (50 mL) were added. The dichloromethane was removed on the rotary evaporator and the solid was collected by filtration. The solid was washed with water (25 mL) and dichloromethane (25 ml) to give a pale blue/green crude solid to be dried under vacuum and used in the next step without additional purification (287 mg). 1H NMR (400 MHz, CDCl3) δ 10.13 (s, 2H), 7.71 (s, 2H).

1. customdry/ice acetone bath with an ice/water bath
2. waitThe reaction mixture was left
3. temperatureto warm to room temperature
4. stirringwhile stirring for 16 hours
5. temperaturebefore cooling to 0° C
6. additionWater (dropwise at first, 150 mL total) and additional dichloromethane (50 mL) were added
7. customThe dichloromethane was removed on the rotary evaporator
8. filtrationthe solid was collected by filtration
9. washThe solid was washed with water (25 mL) and dichloromethane (25 ml)
10. customto give a pale blue/green crude solid
11. customto be dried under vacuum
12. customused in the next step without additional purification (287 mg)

ORD record

ord-4c92af8a1bb8408c8b3a0c021caa4f2a

Source dataset

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09312492B2