2-Bromomesitylene → 1,3-Dimesityltriazene

Participants

Reaction Steps

A THF solution of MesMgBr.LiCl is first prepared by an adaptation the procedure of Knochel et al. To a stirred suspension of magnesium turnings (0.72 g, 30 mmol) and anhydrous LiCl (1.26 g, 30 mmol) in anhydrous THF (40 mL) is added 2-bromomesitylene (5.05 mL, 33 mmol). The exothermic reaction initiates slowly and is allowed to stir overnight at room temperature. To the resulting mixture, which is cooled to 0° C., is added 2-azidomesitylene (4.59 g, 28.5 mmol). Stirring is continued for 1 hour at 0° C., and then an additional 1 hour while allowing to warm to room temperature. The reaction mixture is quenched by pouring the contents into water. A minimum of aqueous NH4Cl is added to neutralize the pH, and the organic products are extracted with Et2O. After washing the combined organic layers with brine, solvents are evaporated at room temperature under reduced pressure to afford a crude product that is recrystallized from Et2O-MeOH to afford 8b (7.41 g, 92%) as off-white needles over 2 crops. 1H-NMR (CDCl3, 300 MHz): δ=9.14 (br s, 1H), 6.93 (br s, 4H), 2.32-2.30 (br m, 18H). M.p.: 92-94° C. (dec). Characterization data for 8b are consistent with literature values.

Provenance & Evidence