Potassium Hydroxide → 6-Bromo-5-chlorobenzo[c][1,2,5]oxadiazole 1-oxide

Temperatur

60 °C

4-Bromo-5-chloro-2-nitroaniline (13.3 g, 53 mmol) was dissolved in 250 mL ethanol, treated with potassium hydroxide (10 g, 88%, 160 mmol) and heated at 60° C. for 2 h. The mixture was cooled to 0-5° C. and treated with dropwise with commercial bleach solution (320 g, 5%, 210 mmol). The cooling was removed and the mixture was stirred for 2 h at 20° C. The mixture was diluted with 1.5 liter of water and the precipitated product was collected by filtration and washed well with water. The wet product was taken up in 250 mL ethyl acetate, washed twice with 50 mL water, 50 mL saturated NaCl, dried (Na2SO4) and evaporated. The residue was chromatographed on silica with a 0-40% ethyl acetate-hexane gradient to give the title compound (5.0 g, 38%): mp 123-125° C. 1H NMR (400 MHz, CDCl3) δ 7.91 (s, 1H), 7.68 (s, 1H); EIMS m/z 248.

1. temperatureThe mixture was cooled to 0-5° C.
2. customThe cooling was removed
3. additionThe mixture was diluted with 1.5 liter of water
4. filtrationthe precipitated product was collected by filtration
5. washwashed well with water
6. washwashed twice with 50 mL water, 50 mL saturated NaCl
7. dry with materialdried (Na2SO4)
8. customevaporated
9. customThe residue was chromatographed on silica with a 0-40% ethyl acetate-hexane gradient

ORD-Eintrag

ord-44eadfc336e04e46a9515c0242c4aaec

Quelldatensatz

uspto-grants-2015_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09006250B2