The New Pyrimidine (1,3-dioxane) And Dihydropyrimidine Synthesis Of Ketone Derivatives

Pyrimidine ring is an important stucture of bioactive molecules and widely exist in nature. Dihydropyrimidinones (DHPMs), a kind of important heterocyclic compounds which contains nitrogen, have received great attention from synthetic and medicinal chemists due to their interesting biological and pharmacological activities. Synthesis of biologically highly active new DHPMs has important practical significance and application prospects.In this thesis, the advance of Knoevenagel condensation and Biglneili reaction in recent years is reviewed. For the purpose of developing a new green synthesis method of Knoevenagel condensation and Biglnelli reaction, the synthesis of a novel pyrimido[4,5-d]pyrimidinone derivatives has been tried. The Knoevenagel condensation reaction conditions are optimized, these methods have the advantages of short reaction time, simple work-up procedure, economy, high yield and under envimumently friendly conditions, which are acceptable in the context of green synthesis. This article also examines the antifungal activity of several new dipyrimidinone diphenyl ethers. The main contents of this thesis includes four aspects as below:(1) In aqueous medium, a series of aromatic aldehydes reacted with meldrum’s acid had obtained products of knoevenagel condensation, with the yield90%, otherwise, meldrum’s acid, salicylic aldehyde, yield coumarin-3-carboxylic acid. Products were characterized by IR,1H NMR,13C NMR and HRMS. In the reaction urea participates as a catalyst, and the catalytic efficiency can be improved in the presence of a catalytic amount of acid.(2) In aqueous medium, HClO4as catalyst, a series of aromatic(or heteroaromatic) aldehydes reacted with barbituric acid had obtained products of knoevenagel condensation. The method provided several advantages such as excellent yieds(up to100%) simple operation, mild reaction conditions, short reaction time(0.5-5min). Otherwise, barbituric acid, salicylic aldehyde, urea progress biglnelli reaction yield dihydropyrimidine, and products were characterized by IR,1H NMR. (3) In the synthesis of N-benzoxazole substituted pyrimido[4,5-d]pyrimidinones, the synthesis of benzoxazole was optimized, o-aminophenol derivative reflux in acetic anhydride, obtain the corresponding products, with the yield up to95%compared the original80%.(4) This article also examines the antifungal activity of12new dipyrimidinone diphenyl ethers. Generally speaking, the inhibitory activity sequence of dipyrimidinone diphenyl ethers to four kinds of fungi is, Pythium solani> Gibberlla saubinetii> Fusarium oxysporium f.s.p. niveum> Gibberll nicotiancola, and compounds4-phenyl-4’-phenoxy-bis((5-Acetyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine)(4-1),4-phenyl-4’-(2-trifluoromethyl)-phenoxy-bis((5-Acetyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine)(4-4) has a wide antibacterial spectrum, and well antifungal activity.