Non-Pincer-Type Arene Ru(II) Catalysts for the Direct Synthesis of Azines from Alcohols and Hydrazine under Aerobic Conditions

We report a tandem approach to synthesize symmetrical azines from alcohols and hydrazine hydrate catalyzed by synthesized arene Ru(II) complexes of aroylthiourea ligand. Notably, the catalytic efficiencies of six- and four-membered N,S-chelate ruthenium complexes were evaluated. The catalytic reaction exhibits complete selectivity for symmetrical azines. A diverse range of azines was synthesized in good to high yields using a catalyst loading of 0.5 mol %, in marked contrast to the previous reports. Remarkably, the catalytic reaction operates under aerobic and mild reaction conditions with the release of water as the only byproduct.