Several multicomponent synthetic approaches were elaborated for plenty of novel nitrogen or oxygen heterocycles containing a phosphonate or a phosphine oxide moiety. All multicomponent reactions were optimized through a model reaction in respect of the heating mode, molar ratio of the starting materials, atmosphere, catalyst, temperature, reaction time and solvent applied, and then, the extended preparation of small libraries of structurally-related compounds was performed. Most of the reactions could be considered as “green syntheses”, as they were carried out in the absence of any catalyst and/or solvent using microwave (MW) irradiation or even at ambient temperature. The scaling-up of a MW-assisted synthesis was also elaborated in a continuous flow MW system. Altogether more than 150 heterocyclic organophosphorus compounds were synthesized, among them several derivatives showed moderate or promising activity against the HL-60 cell line and Bacillus subtilis bacteria.

A new method for the synthesis of 3-oxoisoindolin-1-ylphosphine oxides bearing same or different substituents on the phosphorus atom is described. The one-pot three-component reaction of 2-formylbenzoic acid, primary amines and...

A new approach for the preparation of (2-amino-3-cyano-4H-chromen-4-yl)phosphonate derivatives is described. The multicomponent reaction of salicylaldehydes, malononitrile and dialkyl phosphites catalyzed by pentamethyldiethylenetriamine (PMDTA) provided the bicyclic derivatives in high...

The synthesis of novel 3,4-dihydropyrimidin-2(1H)-one-phosphonates was elaborated by the microwave (MW)-assisted three-component Biginelli reaction of β-ketophosphonates, aromatic or aliphatic aldehydes and urea derivatives. The condensation was optimized on a selected model reaction in respect of the reaction parameters, such as the heating method, the type of the catalyst and solvent, the temperature, the reaction time and the molar ratio of the starting materials. The fast and solvent-free MW-assisted procedure was then extended for the preparation of further new 3,4-dihydropyrimidin-2(1H)-one-phosphonate derivatives starting from different aromatic aldehydes, β-ketophosphonates and urea derivatives to prove the wide scope of the process. As a novel by-product of the Biginelli-type synthesis of 3,4-dihydropyrimidin-2(1H)-one-phosphonates, the 5-diethoxyphosphoryl-4-phenyl-6-styryl-3,4-dihydropyrimidin-2(1H)-one was also isolated and characterized. Our MW-assisted method made also possible the condensation of aliphatic aldehydes, diethyl (2-oxopropyl)phosphonate and urea, which reaction was previously reported to be impossible in the literature.

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Organophosphorus compounds play an important role in the medicinal-or agricultural industry, and in the human body as well. Over the last years, heterocyclic phosphonates have received an intensively growing interest due to their potential biological activity. An efficient tool for the preparation of such derivatives is their synthesis via multicomponent reactions. These transformations possess several criteria of an "ideal synthesis", such as the high atom economy, the fast and simple accomplishment, the energy efficiency and the environmentally friendliness. A number of heterocyclic phosphonates were prepared by us utilizing multicomponent syntheses. In this proceeding, the synthesis of the diethyl (2-amino-3-cyano-4H-chromen-4-yl)phosphonate by the condensation of salicylaldehyde, malononitrile and diethyl phosphite is briefly introduced. The reaction was optimized in respect of the catalyst type, the catalyst amount, the reaction time, and the temperature.

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