Although different methods for the synthesis of Biginelli’s products were based on the use of strong protic .. Pyrimidine and its derivatives. A Mini Review: Biginelli Reaction for the Synthesis of Dihydropyrimidinones. Conference Pyrimidine Containing Derivatives Scheme 7. At the present time there are a few general methods of the synthesis of 5-acyl-1,2, 3,4-tetrahydropyrimidinethiones/ones. One of them is the Biginelli reaction.
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Atul Kumar has reported first enzymatic synthesis for Biginelli reaction via yeast catalysed protocol in high yields. Indexed in Science Citation Index Expanded. The nucleophilic addition of urea synthexis the intermediate 4which quickly dehydrates to give the desired product 5. Introduction Tetrahydroprymidines and their derivatives have recently attracted considerable interest thanks to their pharmacological activities such as anticancer 1antiviral 2calcium channel modulation 3 and antibacterial activity 4 pyrimjdine 6.
This unexpected result leads us to perform further extensive survey in literature to discover the effect of hydrazine hydrate on pyrimidines other than DHPMs.
Journal of Chemistry
In other projects Wikimedia Commons. In general terms, this report is going to describe the synthesis of new tetrahydropyrimidine derivatives via the Biginelli reaction using HCl or DABCO as a catalyst in ethanol.
The 13 C NMR spectra of these compounds showed a signal at about In 1 H NMR spectra, all of the products showed a singlet peak at about 5. An Efficient Synthesis of 5-Alkoxycarbonyl- 4-aryl-3,4-dihydropyrimidin-2 1H -ones”.
The reaction of C5 esters with thiosemicarbazide, in acetone, to afford thiosemicarbazones 6 is reported Figure 1 [ 39 ]. Two singlet peaks for NH groups in pyrimidine ring were observed at about Interestingly, the reported findings revealed that the synthwsis of pyrimidine-2 1 H -one 7a4-methylpyrimidin-2 1 H -one 7bor 4,6-dimethylpyrimidin-2 1 H -one 7c resulted in the formation of 1 H -pyrazole 8a3-methyl-1 H -pyrazole 8b and 3,5-dimethyl-1 H -pyrazole 8crespectively, in addition to urea 1a in each case Figure 2 [ 40 ].
The nonisolable carbohydrazide intermediates are formed firstly followed by the intermolecular nucleophilic attack of terminal amino group of hydrazide function on sp 2 C6 rather than the sp 3 C4 to give the ring adduct which was produced as a final product. Melting points were measured with a Stuart melting point apparatus and were uncorrected.
General procedure for synthesis of tetrahydropyrimidine derivatives A mixture of an ethyl benzoylacetate syntjesis mmolaromatic aldehyde 1 mmolthiourea 1 mmol and an amount of concentration Hydrochloric acid or DABCO 0. National Center for Biotechnology InformationU. Received Mar; Accepted Oct.
Solvent-Free Ring Cleavage Hydrazinolysis of Certain Biginelli Pyrimidines
El Kerdawy et al. The results are shown in Table 2. Biologically active dihydropyrimidones of the Biginelli-type -a literature survey. The benzaldehyd derivatives with substitution in aromatic ring with 4-chloro, 3,4-dimethox, 4-methoxy, 4-methyl, 3-nitro, 2-hydroxy, 5-bromohydroxy, 4-isopropyl and 4-hydroxy groups were reacted with thiourea and ethyl benzoylacetate in the presence of HCl or DABCO as a catalyst under reflux condition to prepare a series of tetrahydropyrimidine derivatives scheme1Table 3.
The latter reaction gave three products, none of them being the expected hydrazide 11a — 11h.
A New Synthesis of Biginelli Compounds
Graphical abstract figure shows the ring opening of certain Biginelli pyrimidines using hydrazine. Support for anN-Acyliminium Ion Intermediate1″. After reaction completion, the reaction mass was cooled and treated with crushed ice.
Antibacterial activities of compounds 1- 4, 6 and 8- 10 were measured on three gram negative bacteria E. Author information Article notes Copyright and License information Disclaimer. This reaction was developed by Pietro Biginelli in View at Google Scholar B. Said1 Wagdy M.
The reaction mixture was allowed to cool and poured on crushed ice. Kabil5 Nasser S.
Dihydropyrimidinones, the products of the Biginelli reaction, are widely used in the pharmaceutical industry as calcium channel blockers,  antihypertensive agentsand alphaa-antagonists.
Melting points were determined with an Electrothermal digital apparatus and were uncorrected. Table 2 MIC values of some synthesized compounds. Ghabbour3,4 Maha M. Highly versatile solid phase synthesis of biofunctional 4-aryl-3,4-dihydropyrimidines using resin-bound isothiourea building blocks and multidirectional resin cleavage. According to Table 3the best results were obtained in the presence of DABCO as a catalyst where the products were achieved with high yields and shorter reaction times.
View at Google Scholar C. A mixture of DHPMs 4a — 4h 0. To receive news and publication pyrumidine for Journal biginepli Chemistry, enter your email address in the box below. From Wikipedia, the free encyclopedia. The latter data stimulate our interest to investigate the reactivity of C5 ester towards hydrazine hydrate under solvent-free conditions which produce three different ring cleavage products.
Cephalexin was used as the standard antibacterial agent. Table of Contents Alerts.
However, C5 esters reacted with hydrazine hydrate, in ethyl alcohol and in the presence of H 2 SO 4to give hydrazides 5 [ 3738 ] Figure 1. Pgrimidine reaction mechanism of the Biginelli reaction ysnthesis a series of bimolecular reactions leading to the desired dihydropyrimidinone. The Biginelli reaction is one of the simple and direct methods for the synthesis of tetrahydropyrimidines, originally reported by Biginelli 7.
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