PROOF Copyright © The Chemical Society of Japan Chemistry Letters Vol.41, No.9 (2012) 1 Combined Thiourea Dioxide-Water: An Eective Reusable Catalyst for the Synthesis of Polyhydroquinolines via Hantzsch Multi- component Coupling MCR CHO TUD (cat) N H O O O O O OR' O O An aqueous solution of thiourea dioxide was found to be a recyclable catalytic media for the efficient synthesis of polyhydroguinoline derivatives via one-step coupling of three component coupling reaction. Neeraj Kumar, Sanny Verma, and Suman L. Jain* CL-120420