The Study Of The Synthesis Of Pyrimidinone And Xanthene

Multicomponent reactions (MCRs) is generally defined as any process in which three or more reactants combine in one pot to form a product that incorporates structural features of each reagent. MCRs have been refined in recent years into powerful and useful tool in synthetic chemistry and attract increasing attention due to the fact that complex molecules and drugs can be prepared from cheap and easily available starting materials. Biginelli reaction is one of important MCRs, which combines an aldehyde, urea and acetoacetic ester under strongly hydrochloric acid conditions in ethanol to give a monocyclic 3,4-dihydropyrimidin-2(lH)-ones (DHPMs). DHPMs and its'derivatives have an extensive application in the realm of antimicrobes, antiviral, antitumor, anti-inflammatory, antibacterial and antimould due to their important therapeutic and pharmacological properties.Xanthene derivatives constitute a structural unit in a number of natural products, and have been used as versatile synthons because of the inherent reactivity of the inbuilt pyran ring. Xanthene derivatives are an important class of compounds as they exhibit wide range of biological and pharmaceutical activities such as antiviral, hpyerglycemic, antianaphylaxis, antibacterial and antiinflammatory agents.People are more interesting in 1,2,3-triazole compounds because of their broad-spectrum biological activity. The compounds have antivirotic, sterilization, antiphlogistic, proliferation inhibition and inhibite diffusion abevacuation of tumor activity.In this paper,Biginelli reaetion was extensively investigated in the presenee of NH2SO3NH4, In(NO3)3 as the catalyst. In order to obviously improve or intensify the biological activities of products, we designed and have synthesized a series of novel DHPMs derivatives and octahydroquinazolinones which containing triazole ring systems through Biginelli reaction.The major accomplishments of the thesis:1 A simple, efficient procedure for the one-pot Biginelli condensation reaction of aromatic aldehydes,β-keto esters and urea or thiourea employing lanthanum nitrate as a novel catalyst is described.2 3,4-dihydropyrimidin-2(1H)-(thio)ones were synthesized via one-pot reaction of aldehydes,β-dicarbonyl compounds and urea or thiourea using nitrate indium (â…¢) as a catalyst. This is a mild, time-saving, high-yielding method, nitrate indium can also be used repeatedly.3 A series of octahydroquinazolinones were synthesized by concentrated H₂SO₄ in the presence ofβ-cyclohexanedione, 2-Aryl-4-formyl-1,2,3-triazole and urea or thiourea. 4 The condensation reaction of 2-Aryl-4-formyl-1,2,3-triazole instead of theordinary aldehydes withβ-cyclohexanedione was investigated by acrylonitrile as a reaction medium, employing Mg(ClO₄)₂ as the catalyst. It was found that when it was carried out in the presence of Mg(ClO₄)₂, its selectivity gave the xanthenes. Further study showed that without additional catalyst this reaction could give xanthenediones ring-opening derivatives.