Started from citric acid (CA) and ethylenediamine derivatives, a solvent-free, catalyst-free and highly yield synthesis approach for bicyclic 2-pyridones was presented. Continuing to modify the core structure, a series of...
AbstractEfficient syntheses of 3,4-dihydropyrimidin-2-(1H)-ones and the corresponding thioxo derivatives using 1,3-dibromo-5,5-dimethylhydantoin (DBH) catalysis of a one-pot three-component Biginelli reaction of aldehydes, ethyl acetoacetate, and urea or thiourea under microwave irradiation are described. The advantages of this method are its short reaction times, high yields of the products, inexpensive and commercially available catalyst, and solvent-free conditions. Typical isolated yields exceed 70 % for arylaldehydes (9 examples) and aliphatic aldehydes (2 examples).
The synthesis of 3-(aryl(piperidin-1-yl)methyl)-4-hydroxyquinolin-2(1H)-one derivatives
via catalyst-free multicomponent reaction is described. The reaction of 4-hydroxyquinolin-2(1H)-one,
piperidine, and 4-chlorobenzaldehyde was carried out in different solvents and under solvent-free conditions
at room temperature. The best solvent in terms of the yield and reaction time was found to be
dichloromethane. Most substituted benzaldehydes reacted with 4-hydroxyquinolin-2(1H)-one and
piperidine to afford corresponding products in good-to-excellent yields. Aldehydes with electronwithdrawing
groups were more reactive to exhibit higher reaction rates. However, 2-substituted benzaldehydes
did not react with 4-hydroxyquinolin-2(1H)-one and piperidine under the reaction condition.
Aldehydes bearing a hydroxyl group failed to produce the corresponding products.
Green High-Yielding One-Pot Approach to Biginelli Reaction under Catalyst-Free and Solvent-Free Ball Milling Conditions