Bromine → 4-Bromo-7-chlorobenzo[c][1,2,5]oxadiazole

Temperature

50 °C

4-Chlorobenzo[c][1,2,5]oxadiazole (1.0 g, 6.5 mmol) was treated with iron powder (14 mg, 0.2 mmol), stirred and heated to 50° C. and then treated in portions with bromine (1.1 g, 7.1 mmol) to produce a homogeneous red melt solution. The flask was fitted with a reflux condenser and the temperature was raised to 85° C. and stirred for 60 min. An additional 450 mg of bromine were added, heating was continued for 1 h more and then the mixture was allowed to stand for 18 h at 20° C. The solid contents of the flask were dissolved in 15 mL dichloromethane and stirred for 30 min with 15 mL saturated Na2SO3 solution. The mixture was diluted with 30 mL ethyl acetate and the organic phase was washed with 15 mL saturated NaCl, dried (Na2SO4) and concentrated under vacuum. The material was chromatographed on silica with a 0-7% ethyl acetate-hexane gradient to give the title compound as a white solid (1.4 g; 93%): mp 81-83° C.; 1H NMR (400 MHz, CDCl3) δ 7.58 (d, J=7.5 Hz, 1H), 7.33 (d, J=7.5 Hz, 1H); EIMS m/z 232.

1. customto produce a homogeneous red melt solution
2. customThe flask was fitted with a reflux condenser
3. temperaturethe temperature was raised to 85° C.
4. stirringstirred for 60 min
5. temperatureheating
6. waitto stand for 18 h at 20° C
7. washthe organic phase was washed with 15 mL saturated NaCl
8. dry with materialdried (Na2SO4)
9. concentrationconcentrated under vacuum
10. customThe material was chromatographed on silica with a 0-7% ethyl acetate-hexane gradient

ORD record

ord-d7d0b4b3955546ae86e0af569bd74c62

Source dataset

uspto-grants-2015_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09006250B2