Reaction #55605

Reaction equation

hydrochloric acid

sodium nitrite

5-amino-3,4-dichloro-α,α,α-trifluorotoluene

→

3,4,5-trichloro-α,α,α-trifluorotoluene

Yield 55.0%

Solvents

water

Conditions

Workup

1. 1
   Filtrationthen filtered
2. 2
   workup.ADDITIONThe filtrate is added to a solution of cuprous chloride (76.5 g.) in concentrated hydrochloric acid (500 ml.) over 5 minutes at 0° to 8° C.
3. 3
   TemperatureThe reaction mixture is cooled to 35° C.
4. 4
   Extractionextracted with hexane (2×300 ml.)
5. 5
   WashThe extract is washed with water, 2% sodium hydroxide solution
6. 6
   Otherdried
7. 7
   workup.DISTILLATIONdistilled

Procedure

A solution of sodium nitrite (39 g.) in water (85 ml.) is added over 1 hour to a solution of 5-amino-3,4-dichloro-α,α,α-trifluorotoluene (117.5 g., 0.51 mol) in 1700 ml. concentrated hydrochloric acid at -6° C. and the solution stirred for 1 hour then filtered. The filtrate is added to a solution of cuprous chloride (76.5 g.) in concentrated hydrochloric acid (500 ml.) over 5 minutes at 0° to 8° C. and gradually heated to 80° C. over 80 minutes. The reaction mixture is cooled to 35° C. and extracted with hexane (2×300 ml.). The extract is washed with water, 2% sodium hydroxide solution, dried and distilled to give 3,4,5-trichloro-α,α,α-trifluorotoluene (70 g., 55%) b.p. 82°-86° C./10 mm, 95% pure.

Source