Reacción #1833243

Ecuación de reacción

3-Bromo-6-fluorobenzene-1,2-diol

thiophosgene

sodium hydroxide

→

title compound

Rendimiento 58.0%

4-Bromo-7-fluorobenzo[d][1,3]dioxole-2-thione

Rendimiento 58.0%

Disolventes

chloroform

Condiciones de reacción

Tratamiento posterior

1. 1
   Otromost of the chloroform was removed by rotary evaporation
2. 2
   workup.ADDITIONThe pH was adjusted to 2 by addition of 1 M HCl
3. 3
   LavadoThe organic phase was washed with water (25 mL), saturated NaCl (25 mL)
4. 4
   Secadodried (Na2SO4)
5. 5
   Otroevaporated
6. 6
   OtroThe crude product was purified by flash chromatography
7. 7
   Lavadoeluting with a 0-20% ethyl acetate-hexane gradient

Procedimiento

3-Bromo-6-fluorobenzene-1,2-diol (8.9 g, 43 mmol) was dissolved in chloroform (100 mL), cooled to 0-5° C. and treated with thiophosgene (5.4 g, 47 mmol). Aqueous sodium hydroxide solution (10 wt %; 40 g, 99 mmol) was added in portions over 30 min with vigorous stirring. Stirring was continued for 60 min at 5-15° C. and then most of the chloroform was removed by rotary evaporation. The pH was adjusted to 2 by addition of 1 M HCl and the precipitated thione was taken up in ethyl acetate (150 mL). The organic phase was washed with water (25 mL), saturated NaCl (25 mL), dried (Na2SO4), and evaporated. The crude product was purified by flash chromatography, eluting with a 0-20% ethyl acetate-hexane gradient to give the title compound as a tan solid (6.2 g, 58%): mp 72-76° C.; 1H NMR (400 MHz, CDCl3) δ 7.40 (dd, J=9.2, 4.1 Hz, 1H), 7.04 (t, J=9.1 Hz, 1H); 19F NMR (376 MHz, CDCl3) δ −132.68; EIMS m/z 248.

Fuente