One-pot Synthesis Of Six-membered Heterocycles In Water

In the research of realizing green chemistry, looking for the green solvents for the friendly environment is one of the main research areas. Water is the abundant solvent in the nature, it is clean, cheap and no noxiousness. The organic reaction in the water phase is operated easily and safely without flammability and explosion. The water molecules have certain steric structures, and the molecules depend on the strong direction hydrogen bonds, all the hydrogen bonds compose a net with a certain steric structures. Water also has high dielectric constant and cohesive energy density. Comparing with organic solvent, the organic reaction in the water has special properties such as hydrophobic effect and chelate effect.In this paper, we synthesized 9 six-membered heterocycles in water. All the compounds were characterized by IR and NMR. This paper firstly gave the choice of the general experiment conditions: Under the potassium carbonate solutions and heating conditions, the reaction could go on easily after adding tetrabutylammonium bromide (TBAB) in the system. And then we did many experiments in varied equivalence of substrates and bases under different temperatures. Finally, we found that 1.0 equiv of aryl amine and 1.0 equiv of aryl ketone could react easily in the present of 2.0 equiv of K2CO3 and 5% equiv of TBAB at the temperature of 70℃. Under this condition, we synthesized 9 six-membered heterocycles and discussed the possible mechanism for the reaction. Though we chose the different substituted groups of the substrates, we haven't found it affect the product yields in this paper.In this paper, we used a method that synthesized compounds in water. This method was operated facilely and conveniently. The experiment conditions were easily got. The method accorded with green chemistry theory and illustrated friendly environment principle.