Hydrochloric Acid → 4-Chloro-3-methylbenzenediazonium tetrafluoroborate

Participants

Reaction Steps

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.

Provenance & Evidence