A Novel and Efficient One‐Pot Synthesis of 2‐Aminopyrimidinones and Their Self‐Assembly

A three‐component reaction of benzaldehyde derivatives, methyl cyanoacetate, and guanidinium carbonate affords 2‐amino‐4‐aryl‐1,6‐dihydro‐6‐oxopyrimidine‐5‐carbonitriles and the four‐component reaction of benzaldehyde derivatives, methyl cyanoacetate, and guanidinium hydrochloride in the presence of piperidine leads to piperidinium salts of pyrimidinones. X‐ray crystallography data confirm self‐assembly and H‐bonding in these compounds.     

The Syntheses of Triazinone and Pyrimidinone Biphenyltetrazoles as Angiotensin II Receptor Antagonists

A series of biphenylyltetrazole substituted triazinones and structure-related pyrimidinones are systhesized, and their binding affinities for angiotensin II receptor are reported.     

Functionalization of 2-(S)-isopropyl-5-iodo-pyrimidin-4-ones through Cu(I)-mediated 1,3-dipolar azide-alkyne cycloadditions

A series of 2-(S)-isopropyl-pyrimidinones functionalized at C5 with triazole rings, in which the substituents are found at N-1′ of the triazole ring, were synthesized. Through the azide-acetylene cycloaddition reaction, using CuI as a copper source and ultrasonic waves as an energy source it was possible to obtain products with yields ranging from 79% to 89% within 5 min or less. A preliminary study to gain further insight into the reaction was performed using in situ ReactIR technology.     

Microwave irradiation： Novel and facile methods for the synthesis of new pyrimidinones

We describe here a rapid process for the preparation of new 9-chloromethyl-12-aryl-10,12-dihydrobenzo[5,6]chromeno[2,3-d]pyrimidin-11-ones 5a-d and 10-chloromethyl-7-aryl-7,9-dihydrobenzo[7,8]chromeno[2,3-d]pyrimidin-8-ones 6a-d by two different methods utilizing microwave irradiation. This methodology provides better yields(72%–80%) and high purity of the title compounds.     

Syntheses with nitriles,XCV: Deamination of cytosine derivatives

Summary Treatment of 2-formyl-3-dimethylamino-propenenitrile (1a) and 2-ethoxycarbonyl-3-dimethylamino-propenenitrile (1b), resp., with substituted ureas led to the 2-cyano-3-ureidoacrylates2, which can be cyclized under alkaline conditions to give 5-formyl-5-cyano-, and 5-alkoxycarbonyl-2-oxopyrimidine derivatives3,6, and7. Reaction of3 with isopentylnitrite gave a mixture of the deaminated and oxidized product4 and the oxo derivative5, which was acetalized during the separation step. Similar reaction with the alkoxycarbonyl derivatives7 led to the formation of 1-alkyl-5-alkoxycarbonyl-pyrimidine-2,6-diones8a–d.

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Synthesen mit Nitrilen, 95. Mitt.: Deaminierung von Cytosinderivaten

Zusammenfassung Die Reaktion von 2-Formyl-3-dimethylamino-propennitril (1a) und 2-Ethoxycarbonyl-3-dimethylamino-propennitril (1b) mit substituierten Harnstoffen führte zur Bildung der 2-Cyan-3-ureidoacrlate2, welche unter alkalischen Bedingungen zu den 5-Formyl-, 5-Cyan- oder 5-Alkoxycarbonyl-2-oxopyrimidinen3,6 bzw.7 cyclisiert werden konnten. Reaktion von3 mit Isopentylnitrit ergab eine Mischung aus deaminiertem und zugleich oxidiertem Produkt4 sowie dem Oxoderivat5, welches während der Säulentrennung auf Kieselgel zusätzlich acetalisiert worden war. Die ähnliche Reaktion mit den Alkoxycarbonyl-Derivativen7 führte zur Bildung der 1-Alkyl-5-alkoxycarbonyl-pyrimidin-2,6-dione8a–d.

     

Synthesis of Heterocyclic Compounds Catalyzed by Metal/Metal Oxide‐Multiwall Carbon Nanotube Nanocomposites

Metal/metal oxide‐decorated multiwalled carbon nanotubes (MWCNTs ) have been found to be effective over various catalysts because of the synergistic, hybrid, physical, and chemical properties of such nanotubes. These properties make them highly active catalytic tools with excellent chemoselectivity, low catalyst loading, and high recyclability of the catalyst. Here, we discuss some recent findings related to the following topics: (1) synthesis of metal/metal oxide‐decorated MWCNTs , (2) characterization techniques of heterogeneous nanocomposites, and (3) application of these metal/metal oxide nanocomposites for the synthesis of heterocyclic compounds. This review emphasizes the main requirements for developing new nanocomposites for the synthesis of pharmaceutically important heterocycles.     

含2-苯基-1,2,3-三唑色酮及嘧啶类化合物的合成

报道了取代邻位羟基苯乙酮(Ⅰ_a-Ⅰ_e)与2-苯基-1,2,3-连三唑-4-甲酸缩合制得酚酯(Ⅱ_a-Ⅱ_e),Ⅱ_a-Ⅱ_e经重排得1,3-二酮化合物(Ⅲ_a-Ⅲ_e),Ⅲ_a-Ⅲ_e在本酸性催化条件下环化为2-位连杂环色酮(Ⅳ_a-Ⅳ_e),Ⅲ_a-Ⅲ_e分别与脲和硫脲缩合得到嘧啶酮Ⅴ_a-Ⅴ_e和Ⅵ_a-Ⅵ_e.     

Synthesis of novel heterocyclic fused 1,3-diazabuta-1,3-dienes and accompanying rearrangements in their cycloaddition reactions with ketenes: synthesis of heterocyclic fused pyrimidinone derivatives

The reactions of 1,3-diazabuta-1,3-dienes 1 with 2-aminothiophenol have been shown to result in excellent yields of N-benzothiazol-2-yl-N′-aryl benzamidines 2. Their regioselective [4+2] cycloadditions with various ketenes are shown to yield novel benzothiazolo pyrimidinones 4. A similar and convenient protocol for the synthesis of bisthiosubstituted 1,3-diazabuta-1,3-dienes 8 and 9 and interesting rearrangements accompanying their [4+2] cycloadditions with a number of ketenes are described.     

Synthesis of Pyrimidinone and 5‐unsubstituted 4, 6‐diarylpyrimidine‐2(1H)‐ones by Using Nano Magnetic Catalyst under Solvent Free Condition

Nano magnetic‐supported sulfonic acid is found to be a powerful and reusable heterogeneous catalyst for the efficient synthesis of pyrimidinones. In this study we use various ketones such as acetophenone and cyclopentanone instead of β‐keto ester in one‐pot synthesis of pyrimidinone at biginelli like reaction. Our objective is to improve conditions for the synthesis of multicomponent reactions using nano magnetic catalyst under solvent free condition. A number of excellent and significant results have been developed that lead our perspective understanding the effect of the magnetic nanoparticles when they are used as catalysts.     

A cyclative cleavage approach to solid-phase synthesis of annulated pyrimidinones using Baylis-Hillman derivatives

An efficient and robust solid-phase synthesis of 6-substituted-2,5,6,8-tetrahydro-3H-imidazo[1,2-a]pyrimidin-7-ones, 3-substituted-1,3,4,6,7,8-hexahydro-pyrimido[1,2-a]pyrimidin-2-ones and 3-substituted-3,4,6,7,8,9-hexahydro-1H-pyrimido[1,2-a][1,3] diazepin-2-ones from the acetates of Baylis-Hillman adducts employing Michael addition of diamines followed by intramolecular cyclization with cyanogen bromide and, finally, base promoted cyclative cleavage has been developed. The procedure is validated through an automated parallel synthesis of a small library of fourteen compounds of the 3H-imidazo[1,2-a]pyrimidin-7-one series.