Mannich Bases as Enone Precursors for Water-Mediated Efficient Synthesis of 2,3,6-Trisubstituted Pyridines and 5,6,7,8-Tetrahydroquinolines
journal contributionposted on 08.06.2015, 00:00 by Essam Hamied Ahmed Hanashalshahaby, Canan Unaleroglu
A highly efficient, regioselective, and environmentally friendly method has been developed for water-mediated synthesis of 2,3,6-trisubstituted pyridines and 5,6,7,8-tetrahydroquinolines. The introduced method allows easy preparation of various polysubstituted pyridines and 5,6,7,8-tetrahydroquinolines via domino reaction of an enolizable ketone, ammonia and enones derived from different Mannich bases in mild reaction conditions. Montmorillonite K-10 promoted this one-pot three-component reaction and gave both new and known 2,3,6-trisubstituted pyridines and 5,6,7,8-tetrahydroquinolines in good yields. The reaction protocol provides a wide array of functionality in construction of polysubstituted pyridines and 5,6,7,8-tetrahydroquinolines from commercially available starting materials in easily applicable and environmentally friendly conditions.