Sulfur Dioxide → 313681-67-3

Temperature

-30 °C

A solution of 2.37 g (10 mmol) 5-bromo-2,2-difluoro-1,3-benzodioxole in 25 ml anhydrous ether, cooled to −30° C., and 4 ml (10 mmol) n butyllithium (2.5 M in hexanes) was added at −30° C., over 10 minutes. The mixture was stirred at −30° C. for 1 hour, then sulfur dioxide gas was passed through the mixture at −20° C. for 5 minutes. The mixture then was allowed to warm up to 20° C., and the precipitate was filtered and washed with 20 ml hexane. The solid was suspended in 20 ml hexanes, 1.35 g (10 mmol) sulfuryl chloride was added, the mixture was stirred at 20° C. for 48 hours. The mixture then was filtered and the filtrate was concentrated under reduced pressure to obtain 1.6 g (62%) title compound. The product was used in the next step without further purification. 1H-NMR (CDCl3): δ 7.27 (1H,d), 7.74 (1H,s), 7.88 (1H,d).

1. temperatureto warm up to 20° C.
2. filtrationthe precipitate was filtered
3. washwashed with 20 ml hexane
4. stirringthe mixture was stirred at 20° C. for 48 hours
5. filtrationThe mixture then was filtered
6. concentrationthe filtrate was concentrated under reduced pressure

ORD record

ord-3740848763f949a795f393183878675c

Source dataset

uspto-grants-2005_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06878728B1