2,1,3-Benzothiadiazole → 3,6-Dibromobenzene-1,2-diamine

Temperature

70 °C

4,7-dibromobenzo[1,2,5]thiadiazole (6.0 g, 20.3 mmol), prepared according to WO 00/55927 PCT/GB00/00911 by bromination of benzo[1,2,5]thiadiazole, was placed in a 200-mL flask under a nitrogen atmosphere. Zinc dust (13.2 g, 203 mmol) and a mixture of acetic acid/water (35 mL/35 mL) were added. The flask was loosely capped with an inverted 1-neck flask. The reaction mixture was heated to 70° C. for 1 hr at which time reaction was complete as determined by TLC. The mixture was then cooled to room temperature and filtered. The solid was extracted with diethylether (3×100 mL). The extract was washed with saturated aqueous sodium bicarbonate and dried over MgSO4. The solution was filtered and evaporated to dryness using a rotary evaporator. The solid was purified by chromatography on a silica gel column, using dichloromethane as eluent. The appropriate fractions were combined and the solvent was removed under reducing pressure. A light yellow product was obtained. Yield: 70%.

1. customwas placed in a 200-mL flask under a nitrogen atmosphere
2. additionwere added
3. customThe flask was loosely capped with an inverted 1-neck flask
4. temperatureThe mixture was then cooled to room temperature
5. filtrationfiltered
6. extractionThe solid was extracted with diethylether (3×100 mL)
7. washThe extract was washed with saturated aqueous sodium bicarbonate
8. dry with materialdried over MgSO4
9. filtrationThe solution was filtered
10. customevaporated to dryness
11. customa rotary evaporator
12. customThe solid was purified by chromatography on a silica gel column
13. customthe solvent was removed
14. customA light yellow product was obtained

ORD record

ord-e43837a553a64c69bd0c9c6dc153eb8a

Source dataset

uspto-grants-2010_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07714099B2