Sodium Hydroxide → HCID 13458493, compound

Participants

Reaction Conditions

Reaction Steps

A suspension of 42.60 g (0.2 mole) of 2-iminoimidazolidine monohydroiodide in 500 ml THF was treated with 16 g (0.2 mole) of 50% NaOH solution and stirred for 0.5 hour. Twenty grams of anhydrous Na2SO4 were added and the mixture stirred for another 0.5 hour. The mixture was cooled to -20° C. (it was necessary to maintain a temperature of -20° C. at all times to avoid isomerization) under N2 and a solution of 18.71 g (0.1 mole) 2-trifluoromethylphenyl isocyanate in 125 ml THF was added dropwise while stirring over a 3-hour period, maintaining the temperature at -20° C. The mixture sitrred for another hour at -20° C. then the inorganics were filtered off and the solvent was removed cold, in vacuo, to yield a yellow-green oil, which was stirred in cold brine and extracted with 3×150 ml portions of cold CH2Cl2 . The combined CH2Cl2 extracts were dried over anhydrous K2CO3 and filtered. The filtrate was acidified with cold, excess ethereal HCl to pH <3 and was stored in a freezer overnight. The solvent and excess HCl were removed in vacuo and the yellow solid remaining was washed with Et2O to remove excess HCl. The solid (25.2 g; 81.6%) was recrystallized from MeOH/Et2O to yield 17.2 g (55.7%) of impure product, which was recrystallized from MeOH/2-PrOH/Et2O, and finally from MeOH/Et2O to yield 4.7 g (15.2%) of pure hydrochloride salt, m.p. 166.5°-167° C. (dec.), a white solid.

Provenance & Evidence