Synthesis of aryl‐functionalized, 1,5‐disubstituted 1,2,3‐triazoles and derivatives by arylation of zwitterionic ruthenium triazolato complexes

Abstract

AbstractThe synthesis of a series of ruthenium 1,5‐disubstituted 1,2,3‐triazolato complexes, 1,5‐disubstituted 1,2,3‐triazoles, and a triazolium salt is reported. Treatment of the ruthenium azido complex [Ru]‐N3 (1, [Ru] = (η5‐C5H5)(dppe)Ru, dppe = Ph2PCH2CH2PPh2) with an excess of ethyl propiolate results in the formation of a mixture of the Z‐ and E‐forms of zwitterionic N(1)‐bound N(3)‐ethyl acryl‐4‐carboxylate triazolato complexes [Ru]N3(CH=CHCO2Et)C2H(CO2) (Z‐2) and (E‐2). The arylation of 2 with aromatic bromides gives a series of cationic N(1)‐bound N(3)‐ethyl acryl‐4‐alkoxycarbonyl triazolato complexes {[Ru]N3(CH=CHCO2Et)C2H(CO2CH2R)}[Br] (3a, R = Ph; 3b, R = C6F5; 3c, R = 4‐C6H4CN, 3d, R = 2,6‐C6H3F2) and the subsequent cleavage of the Ru‐N bond of 3a–d gives 1,5‐disubstituted 1,2,3‐triazoles N3(CH=CHCO2Et)C2H(CO2CH2R) (4a, R = Ph; 4b, R = C6F5; 4c, R = 4‐C6H4CN; 4d, R = 2,6‐C6H3F2) and [Ru]‐Br. A 1,2,3‐triazolium salt [N3(CH=CHCO2Et)(CH2C6F5)C2H2][Br] (5) was formed by transformation of 4b in BrCH2C6F5/chloroform mixture. The structures of Z‐3a and Z‐5 were confirmed by single‐crystal x‐ray diffraction analysis and both complexes participate in non‐covalent aromatic interactions in the solid‐state structures which can be favorable in the binding of DNA/biomolecular targets and have shown great potential in the application of biologically active anticancer drugs.