Catalytic activity of Ru/tetrahydropyrimidinium salts system for transfer hydrogenation reactions

New 1,3-dialkyltetrahydropyrimidinium salts as NHC precursors have been synthesized and characterized. The in situ prepared three-component 1,3-dialkyltetrahydropyrimidinium salts/[RuCl2(p-cymene)]2 and KOH catalyzes quantitatively the transfer hydrogenation of ketones under mild reaction conditions in 2-propanol. Also, the molecular structure of 1,3-bis(2-methylbenzyl)-3,4,5,6-tetrahydropyrimidinium was determined using single-crystal X-ray diffraction. Ions of the title compound are linked by CH…Cl and OH…Cl hydrogen bonding interactions. The NCN bond angle (124.3(2)°) and CN bond lengths (1.316(3) and 1.314(3) A) confirm the existence of strong resonance in this part of the molecule. Copyright © 2015 John Wiley & Sons, Ltd.