Thionyl Chloride → 5-Bromo-benzo[2,1,3]thiadiazole

To a solution of 4-bromobenzene-1,2-diamine (5.236 g, 28.0 mmol) and Hunig's base (19.5 mL, 112 mmol) in dichloromethane (160 mL) was added SOCl2 (4.08 mL, 56 mmol) dropwise at room temperature. The resulting reaction mixture was heated to reflux overnight. The reaction mixture was then allowed to cool to room temperature, and quenched with 10% HCl until pH=2. The resulting mixture was extracted with dichloromethane (200 mL×4), dried over Na2SO4 and concentrated. The crude compound was purified by flash column chromatography (silica gel, chloroform) to afford 5-bromobenzo[1,2,5]thiadiazole as a brown solid which was used directly in the next step. 1H NMR (CDCl3 500 MHz): δ: 8.21 (d, 1H, J=1.5 Hz), 7.87 (d, 1H, J=8.5 Hz), 7.69 (dd, 1H, J=8.5, 1.5 Hz).

1. customThe resulting reaction mixture
2. temperaturewas heated
3. temperatureto reflux overnight
4. customquenched with 10% HCl until pH=2
5. extractionThe resulting mixture was extracted with dichloromethane (200 mL×4)
6. dry with materialdried over Na2SO4
7. concentrationconcentrated
8. customThe crude compound was purified by flash column chromatography (silica gel, chloroform)

ORD record

ord-7dad997268654f0686f91ab0b62dacf0

Source dataset

uspto-grants-2014_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08723028B2