反应详情

温度

-20 °C

A suspension of 21.3 g (0.1 mole) of 2-iminoimidazolidine HI in 250 ml THF was treated with 8 g (0.1 mole) of 50% NaOH solution and stirred for 0.5 hour. Ten grams of anhydrous Na2SO4 were added and the mixture stirred another 0.5 hour. After cooling to -20° C. (it was necessary to maintain a temperature of -20° C. at all times while compound was in free base form to avoid isomerization) under N2, 7.45 g (0.05 mole) of 4-methoxyphenyl isocyanate in 60 ml THF was added dropwise over a 2.5-hour period, maintaining -20° C. The mixture was stirred an additional hour, then the inorganics were filtered off and the solvent was removed in vacuo, cold, to yield a yellow oil, which was stirred in 200 ml cold brine and extracted with 3×100 ml portions of cold CH2Cl2. The CH2Cl2 extracts were dried over anhydrous K2C03, filtered, and the filtrate was acidified to pH<3 with cold excess ethereal HCl, adding MeOH to dissolve any solid which formed. The solution was stored in a freezer overnight. The solvent and excess HCl were removed in vacuo to yield 11.40 g of a yellow-white solid, which was recrystallized from MeOH/Et2O, converted to the free base and back to the HCl salt, and, finally, recrystallized from MeOH/Et2O to yield 3.24 g of pure hydrochloride salt, m.p. 199°-201° C. (dec.), a white solid.

1. stirringthe mixture stirred another 0.5 hour
2. temperatureto maintain a temperature of -20° C. at all times while compound
3. temperaturemaintaining -20° C
4. stirringThe mixture was stirred an additional hour
5. filtrationthe inorganics were filtered off
6. customthe solvent was removed in vacuo
7. customcold, to yield a yellow oil, which
8. extractionextracted with 3×100 ml portions of cold CH2Cl2
9. dry with materialThe CH2Cl2 extracts were dried over anhydrous K2C03
10. filtrationfiltered
11. additionadding MeOH
12. dissolutionto dissolve any solid which
13. customformed
14. waitThe solution was stored in a freezer overnight
15. customThe solvent and excess HCl were removed in vacuo