摘要：

A.N,N'-1,3-Bis(2,6-diisopropylphenyl)imidazolium chloride(2).In air,a 2000-mL one-necked,round-bottomed flask(24/40),equipped with a Teflon-coated egg-shaped magnetic stirbar(3/4"x 2"),is charged with MeOH(250 mL)(Note 2),2,6-diisopropylaniline(210 mL,200 g,1.0 mol,2.0 equiv)(Note 2)and AcOH(1.0 mL,1.1 g,18 mmol,0.035 equiv)(Note 2).In a 500-mL one-necked round-bottomed flask(24/40),glyoxal(60 mL,73 g,0.50 moL 1.0 equiv)(Note 3)is dissolved in MeOH(250 mL).The resulting solution in the 500-mL flask is then added via a glass funnel to the 2000-mL flask over 2min.The 2000-mL reaction flask is equipped with a reflux condensor,which is sealed with a rubber septum(Note 4)(Figure 1A)and placed into an oil bath(preheated at 50 ℃).The reaction mixture is stirred(Note 5)at 50 ℃(Note 6)for 15 min(Note 7),after which the oil bath is removed to allow the reaction mixture to cool to room temperature(Note 8)over 30 min.Subsequently,the reaction mixture is stirred(Note 5)at room temperature(Note 8)for an additional 10 h(Figure IB),the resultant yellow solid is collected by filtration(Note 9)and rinsed with MeOH(3 x 200 mL)in a glass fritted funnel(Note 10)(Figure 1C).The resulting yellow solid is transferred to a 1000-mL one-necked round-bottomed flask(24/40)and volatiles are removed on a rotary evaporator(35 mmHg,40 ℃,20 min)(Note 11)followed by further drying under vacuum(Note 12)at room temperature(Note 8)for 16 h to afford 167 g(89%)of N,N'-l,4-bis(2,6-diisopropylphenyl)-l,4-diazabutadiene as a yellow solid(Note 13).

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