Abstract
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.
Highlights
A wide number of organophosphorus compounds play an important role in different fields of life; in organic- and medicinal chemistry, as well as in the agriculture and plastic industries [1]
The condensation was followed by 31 P NMR spectroscopy, At first, the model of by diethyl benzaldehyde and the crude products werereaction analyzed
4-chlorobenzaldehyde, 0.16 mL 4-fluorobenzaldehde, 0.38 g 2-fluoro-4-iodobenzaldehyde, 0.18 mL 3-methylbenzaldehyde, 0.18 g 4-hydroxybenzaldehyde, 0.23 g 4-nitrobenzaldehyde, 0.29 g 3,4,5-trimethoxybenzaldehyde, 0.14 mL butyraldehyde or 0.16 mL isovaleraldehyde), 2.0 mmol urea derivative (0.12 g urea or 0.14 g N-methylurea) and 0.15 mmol (0.05 g) zinc triflate was irradiated in a sealed tube at 100 ◦ C for 2 h in a CEM Microwave reactor equipped with a pressure controller
Summary
A wide number of organophosphorus compounds play an important role in different fields of life; in organic- and medicinal chemistry, as well as in the agriculture and plastic industries [1]. Organic phosphonates may be considered as one of the most important subgroups. Α-aminophosphonates are the bioisosteres of natural α-amino acids, and due to this structural similarity, they were proved to be effective as antibiotics, antiviral, or antitumor agents, as well as pesticides [2,3,4,5,6]. ΑAminophosphonates containing a piperidine ring (1) showed activity as an insecticide against Plutella xylostella [9]. To the 1,4-dihydropyridine3,5-dicarboxylates, several 1,4-dihydropyridine-5-phosphonates (3) showed significant antihypertensive activity [11,12,13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
