Reaction #1833216

Reaction equation

sodium iodide

sodium nitrite

2,2,6-Trifluorobenzo[d][1,3]dioxol-5-amine

hydrochloric acid

sodium bisulfite

→

title compound

Yield 51.0%

2,2,5-Trifluoro-6-iodobenzo[d][1,3]dioxole

Yield 51.0%

Solvents

dichloromethane

water

water

Conditions

Workup

1. 1
   workup.STIRRINGStirring
2. 2
   workup.STIRRINGstirred for 20 min more
3. 3
   OtherThe phases were separated
4. 4
   Extractionthe aqueous phase was extracted with dichloromethane (75 mL)
5. 5
   WashThe combined organic phases were washed with saturated NaCl (30 mL)
6. 6
   Dryingdried (Na2SO4)
7. 7
   Otherevaporated
8. 8
   OtherThe residue was purified by chromatography on silica with hexane

Procedure

2,2,6-Trifluorobenzo[d][1,3]dioxol-5-amine (8.0 g, 42 mmol) was added to concentrated hydrochloric acid (conc. HCl; 200 mL), cooled to 5° C., vigorously stirred and treated dropwise with a solution of sodium nitrite (4.3 g, 63 mmol) in water (10 mL) over 10 min. Stirring was continued for 30 min at 5-10° C. and the mixture was poured cautiously into a solution of sodium iodide (19 g, 130 mmol) in water (200 mL), rapidly stirred with dichloromethane (100 mL). After 20 min the mixture was treated with 10% sodium bisulfite solution (NaHSO3; 20 mL) and stirred for 20 min more. The phases were separated and the aqueous phase was extracted with dichloromethane (75 mL). The combined organic phases were washed with saturated NaCl (30 mL), dried (Na2SO4) and evaporated. The residue was purified by chromatography on silica with hexane to give the title compound as a clear liquid (6 g, 51%): 1H NMR (400 MHz, CDCl3) δ 7.41 (d, J=5.0 Hz, 1H), 6.90 (d, J=6.6 Hz, 1H); 19F NMR (376 MHz, CDCl3) δ −49.63 (s), −95.24 (s); EIMS m/z 302.

Source