Reaction #1885032

Reaction equation

sodium tetrafluoroborate

4-chloro-3-methylaniline

HCl

sodium nitrite

→

4-chloro-3-methylbenzenediazonium tetrafluoroborate

Yield 95.2%

Solvents

water

water

water

Conditions

Workup

1. 1
   OtherSynthesized
2. 2
   workup.ADDITIONwas added in one portion
3. 3
   FiltrationThe solid was filtered
4. 4
   Washwashed with cold (5° C.) diethyl ether (10 mL)
5. 5
   workup.DISSOLUTIONThe solid was dissolved in acetone (15 mL)
6. 6
   Filtrationfiltered
7. 7
   workup.ADDITIONTo the filtrate was added diethyl ether (15 mL)
8. 8
   Otherthe precipitation of the arenediazonium tetrafluoroborate
9. 9
   FiltrationThe solid was filtered
10. 10
    Washwashed with cold (5° C.) diethyl ether (5 mL)
11. 11
    Otherair dried overnight

Procedure

Synthesized according to General Procedure 1. 4-chloro-3-methylaniline (5 g, 35.3 mmol) in water (15 mL) and conc. HCl (9.5 mL, 116.5 mmol) at −5° C. was added a freshly prepared aqueous solution of sodium nitrite (3.2 g, 45.9 mmol) in water (8 mL) slowly over 10 minutes. After stirring for 15 minutes at −5° C. a freshly prepared aqueous solution of sodium tetrafluoroborate (5.4 g, 49.4 mmol) in water (14 mL) was added in one portion causing the formation of a precipitate. The solid was filtered and washed with cold (5° C.) diethyl ether (10 mL). The solid was dissolved in acetone (15 mL) and filtered. To the filtrate was added diethyl ether (15 mL) causing the precipitation of the arenediazonium tetrafluoroborate. The solid was filtered, washed with cold (5° C.) diethyl ether (5 mL) and then air dried overnight to provide 4-chloro-3-methylbenzenediazonium tetrafluoroborate (8.07 g, 33.6 mmol, 95% yield) as a tan solid. 1H-NMR (400 MHz, DMSO-d6) δ 8.68 (d, J=2.2 Hz, 1H), 8.56 (dd, J=2.4, 8.8 Hz, 1H), 8.10 (d, J=8.8 Hz, 1H) and 3.47 (s, 3H) ppm. LC/MS (10%-99% CH3CN (0.035% TFA)/H2O (0.05% TFA), m/z: M+1 obs=125.0; tR=0.24 min.

Source