1,3-BIS(2,6-DIISOPROPYLPHENYL)IMIDAZOLIUM CHLORIDE

White, off-white or tan powder

Charging a 1000 mL round bottom flask with methanol (500 mL), 2, 6-diisopropylaniline (63.8 mL, 340 mmol), glyoxal (40 wt percent soln in water, 19 mL, 170 mmol), and formic acid (1 mL).Stirring the resulting mixture for 3 hours at room temperature.Filtering the yellow precipitate, (3) (Diagram D)Washing precipitate with cold methanol.Drying precipitate in vacuo overnight (70percent, 44.2 g, 238 mmol).Charging a 5 L round bottom flask with precipitate (3) (200 g, 532 mmol) and ethyl acetate (2 L).Stirring the resulting mixture until (3) was dissolved.Cooling the solution to 0° C. but this can be carried out at room temperature.Charging a 500 mL Erlenmeyer flask with paraformaldehyde (20.7 g, 690 mmol), HCl (4N in dioxane, 212 mL, 851 mmol).Stirring this solution for 10 minutes, then added.Stirring the resulting mixture for 2 hours at room temperature.Filtering precipitateDissolving precipitate in methanol (200 mL).Adding 15.0 g of sodium bicarbonate.Stirring the solution for 1 hour or until there is no more carbonation.Filtering the solution to remove the solids.Reprecipitating the product with 250 mL of diethyl etherCollecting product by filtrationWashing product with diethyl ether.Drying the product in vacuo to yield IPr.HCl (4) as a white powder (70percent, 158.25 g, 371 mmol). Synthesizing of l, 3-Bis(2, 6-dsopropylphenyl)imidazolium chloride (IPr HCl, 4) by:; Charging a 1000 mL round bottom flask with methanol (500 mL), 2, 6- diisopropylaniline (63.8 mL, 340 mmol), glyoxal (40wt percent soln in water, 19 mL, 170 mmol), and formic acid (ImL).Stirring the resulting mixture for 3 hours at room temperature. Filtering the yellow precipitate, (3) (Diagram D)Washing precipitate with cold methanol.Drying precipitate in vacuo overnight (70percent, 44.2 g, 238 mmol).Charging a 5 L round bottom flask with precipitate (3) (200 g, 532 mmol) and ethyl acetate (2 L). Stirring the resulting mixture until (3) was dissolved.Cooling the solution to 0° C but this can be carried out at room temperature.Charging a 500 mL Erlenmeyer flask with paraformaldehyde (20.7 g, 690 mmol), HCl (4N in dioxane, 212 mL, 851 mmol).Stirring this solution for 10 minutes, then added. Stirring the resulting mixture for 2 hours at room temperature.Filtering precipitateDissolving precipitate in methanol (20OmL).Adding 15.Og of sodium bicarbonate.Stirring the solution for 1 hour or until there is no more carbonation. Filtering the solution to remove the solids.Reprecipitating the product with 250 mL of diethyl etherCollecting product by filtrationWashing product with diethyl ether.Drying the product in vacuo to yield IPrHCl (4) as a white powder (70percent, 158.25g, 371 mmol). 37.6 g (100 mmol) of bis(2, 6-diisopropylphenyl)diazabutadiene, 1.68 g (100 mmol) of formaldehyde solid, 160 mL of toluene were added to a 500 mL three-neck round bottom flask. Stirred refluxed at 50° C. for 1 h until most of the formaldehyde dissolved. The reaction mixture was cooled to 40° C. and a solution of HCl in dioxane 58 mL (100 mmol, 1.723 mol/L) was added with a syringe.The color of the solution changed from yellow to red to brown, with the development of a white solid. The reaction was stirred and refluxed at 40° C. for 40 h, suction filtered and washed three times with THF to give a pink solid mass. About 40 mL of anhydrous ethanol was added to dissolve, the solvent was derotated, the solid was turned into a powder, and washed three times with THF to obtain 21.94 g of an off-white powder HIPrCl (yield 51.7percent).

Important pharmaceutical intermediates

Molecular Weight:425.0
Hydrogen Bond Acceptor Count:1
Rotatable Bond Count:6
Exact Mass:424.2645269
Monoisotopic Mass:424.2645269
Topological Polar Surface Area:8.8
Heavy Atom Count:30
Complexity:421
Covalently-Bonded Unit Count:2
Compound Is Canonicalized:Yes