## 3 Carbon-Nitrogen Forming Reactions
### N-Arylation of Amines, Amides and Nitrogen Containing Heterocycles  
Aryl-nitrogen bonds formed via cross-coupling reactions represent a powerful tool for the production of a number of compounds with practical uses [54]. The original variant of the Ullmann reaction is still utilized for this purpose [55]. However, this method of performing of the reaction is constrained by several disadvantages, e.g., it needs high temperature (150-200 \({}^{\circ}\)C) and the use of stoichiometric amounts of copper [54; 55]. A remarkable simplification was achieved by the use of substituted phenylboronic acids for \(N\)-arylation of imidazole catalysed by copper(II) salts [56]. The next facilitation was the utilization of heterogeneous catalyst **22** (Scheme 14) [57]. Catalyst **22**was prepared from commercial chloromethylylated polystyrene (5.5% DVB), on which \(\beta\)-alanine was attached through the oxygen atom, and copper(II) acetate was coordinated. Less efficient variants of this catalyst were prepared by the coordination with CuCl\({}_{2}\) and CuI. Catalyst **22** was successfully tested for the reaction of substituted phenylboronic acids with nitrogen containing heterocycles (imidazole, benzimidazole; 65-98%) and with amides (phthalimide, benzamide, benzenesulfonamide; 37-98%) under very mild conditions (methanol, 40 \({}^{\circ}\)C, 10-20 h). The reaction with amines was performed in DMSO in the presence of K\({}_{2}\)CO\({}_{3}\) at 140 \({}^{\circ}\)C (aniline, benzylamine; 58-91%) (Scheme 14) [57]. The recovery and reuse of catalyst **22** was studied for the reaction of phenylboronic acid with imidazole (Cycle 1: 98%; Cycle 6: 90%) and aniline (Cycle 1: 86%; Cycle 4: 82%). In both cases, only a slight decrease in yields was observed (Scheme 14) [57]. Under comparable conditions as in [57] (cataly **22**), the same authors achieved analogical \(N\)-aryations of N(H)-heterocycles with aryl halogenides and arylboronic acids with good or excellent results with the use of heterogeneous catalysts based on complexes of polystyrene-Schiff bases (PS-4-C\({}_{6}\)H\({}_{4}\)N=CH-2-pyridyl Cu(OAc)\({}_{2}\)) [58], or (PS-4-C\({}_{6}\)H\({}_{4}\)N=CH-2-furyl Cu(OAc)\({}_{2}\)) [59]. Another variant of this reaction is the \(N\)-arylation of imidazole, pyrazole, 1,2,4-triazole, benzylamine and substituted anilines with substituted iodobenzenes catalysed by catalyst **23** (Scheme 15) [60]. Catalyst **23** was prepared from commercial chloromethylated polystyrene (2% DVB), on which 5-phenyl-1\(H\)-tetrarole was attached, and CuCl\({}_{2}\) was coordinated (Scheme 15). The reactions were performed in DMSO at 120 \({}^{\circ}\)C for 12-16 h in the presence of K\({}_{2}\)CO\({}_{3}\) (\(N\)-heterocycles; 67-95%), or in the presence of KOH (amines; 67-85%). In different solvents (THF, MeCN, DME, \(N\)-methylpyrrolidone (NMP), DMF) and under different conditions (Cs\({}_{2}\)CO\({}_{3}\), NaHCO\({}_{3}\), K\({}_{3}\)PO\({}_{4}\), TEA; 80 \({}^{\circ}\)C, 130 \({}^{\circ}\)C)  
Figure 14: \(N\)-Arylation of \(N\)-nucleophiles by substituted phenylboronic acids catalysed by polystyrene supported complex **22**. Figure 15: \(N\)-Arylation of \(N\)-nucleophiles by substituted aryl halides catalysed by polystyrene supported complex **23**. \(N\)-arylation of \(1H\)-imidazole with iodobenzene occurred with lower yields than the reaction in DMSO. The recovery and reusing of catalyst **23** was tested with success for the reaction of imidazole with iodobenzene (Cycle 1: 94%; Cycle 6: 89%). The \(N\)-arylation of amides and lactams with substituted iodobenzenes, bromobenzene, 2-bromopyridine or 2-iodopyridine catalysed by **24** was also successful (Scheme 16) [61]. Catalyst **24** was prepared from commercial chloromethylated polystyrene, where the chloromethyl group was transformed to an aldehyde group. Subsequent reaction with \(\beta\)-alanine led to the production of an imine, which was then coordinated with Cu(II) acetate.