One-pot efficient pseudo-five-components synthesis of 4,4′-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ols) at room temperature assisted by K2CO3

Access to molecular complexity. Multicomponent reactions involving five or more components

The evaluation of the significance of a chemical transformation addresses many factors, including such important characteristics as the number of chemical bonds formed in one step, the reaction time, labour intensity, the cost of reactants and catalysts and so on. The amount of waste produced in the reaction has also gained increasing importance in recent years. Multicomponent reactions (MCRs) occupy a special place as a synthetic tool in modern organic chemistry. These reactions allow the synthesis of target products with complex structures, minimizing labour costs. This review summarizes the literature on multicomponent reactions involving five or more components. The data in the review are classified according to the number of reactants participating in the reaction and the types of reactions. It is worth noting that in some cases, these transformations can be a part of a domino process, making this classification difficult, if not impossible. The structural diversity of the reaction products greatly increases with increasing number of components involved in the MCR, which becomes virtually unlimited when using combinations of MCRs. This review highlights the main trends of past decades in the field of MCRs. The last two decades have witnessed an explosive growth in the number of publications in this area of chemistry.

The bibliography includes 309 references.

Synthesis of 4,4′-(arylmethylene)bis(3-carboxymethyl-1-phenyl-1H-pyrazol-5-ol)s using ionic liquid attached to colloidal silica nanoparticles in water

An efficient synthesis of 10 4,4′-(arylmethylene)bis(3-carboxymethyl-1-phenyl-1 H-pyrazol-5-ol)s, eight of which are novel, was achieved by a one-pot three-component reaction of phenylhydrazine, dimethyl acetylenedicarboxylate and an arylaldehyde using bis(1(3-methoxysilylpropyl)-3-methyl-imidazolium) copper tetrachloride tethered to colloidal silica nanoparticles as catalyst under microwave irradiation in water. The advantages of the present process are atom economy, high catalytic activity, excellent yields, short reaction times and utilisation of microwave heating as a clean procedure. The catalyst was recyclable.