Cu(OTf)₂-catalyzed multicomponent reactions

• Sara Colombo,
• Camilla Loro,
• Egle M. Beccalli,
• Gianluigi Broggini and
• Marta Papis

Beilstein J. Org. Chem. 2025, 21, 122–145, doi:10.3762/bjoc.21.7

• Biginelli reaction was carried out starting from salicylaldehyde providing hydroxyphenyl-substituted dihydropyrimidines 18 [30]. Subsequently, the regioselective oxidation of the dihydropyrimidine ring in the presence of CAN allowed the formation of new pyrimidinone derivatives 19. The efficacy of Cu(OTf)2

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• to the higher concentration of liquid HCl compared to gaseous HCl. A systematic study of hydrochlorination reactions with concentrated solutions of HCl gas in DMPU (1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone) was recently disclosed by Hammond and Xu (Scheme 7) [51]. These solutions were prepared

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• ’-dimethylphosphonodiamides 178, 181, and 183. The corresponding cyclohexadiene-fused γ-phosphinolactam derivatives 179, 180, 182, and 184–188 were obtained after treatment with sec-butyllithium in a mixture of THF and DMPU (1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone) followed by addition of various electrophiles, such

Synthesis and HDAC inhibitory activity of pyrimidine-based hydroxamic acids

• Virginija Jakubkiene,
• Gabrielius Ernis Valiulis,
• Markus Schweipert,
• Asta Zubriene,
• Daumantas Matulis,
• Franz-Josef Meyer-Almes and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 837–844, doi:10.3762/bjoc.18.84

• the Supporting Information File 1. General procedure for the synthesis of esters 3, 4, and 20–24 To a mixture of pyrimidinone 1, 2 or 19 (1 mmol) and TBAB (0.032 g, 0.1 mmol) in TEA (0.4 mL) at 50–60 °C the corresponding bromoester (1.1 mmol) was added dropwise under stirring. The reaction mixture was

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

• generated from trifluoromethyl iodide (CF3I) and Zn dust (or ZnEt2) in 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU) [65] and later isolated [66]. The reaction of Zn(CF3)2(DMPU)2 (2 equiv) with styrenes proceeded efficiently in toluene to provide the difluorocyclopropanes 56 in 53–93% yields

Synthesis of pyrazolopyrimidinones using a “one-pot” approach under microwave irradiation

• Mark Kelada,
• John M. D. Walsh,
• Robert W. Devine,
• Patrick McArdle and
• John C. Stephens

Beilstein J. Org. Chem. 2018, 14, 1222–1228, doi:10.3762/bjoc.14.104

• groups. Keywords: microwave-assisted synthesis; nitrogen-fused heterocycle; one-pot; pyrimidinone; Introduction The pyrazolo[1,5-a]pyrimidinone is a fused nitrogen-containing heterocyclic system and is of interest due to its role as a basic core scaffold in many bioactive and pharmaceutically relevant

• compounds, as well as its structural similarity to purine [1][2][3][4]. Pyrazolo[1,5-a]pyrimidinone derivatives have found use in the battle against several illnesses including cancer [5], viral infections [6][7][8], obesity [9], and cystic fibrosis [10] (Figure 1). It is these pharmacological properties

• convenient and general microwave-assisted method for the synthesis of the 5-aminopyrazoles in hand, we next focused our attention on its application to the one-pot synthesis of pyrazolo[1,5-a]pyrimidinones. The synthesis of pyrazolo[1,5-a]pyrimidinone 3a was chosen as the model reaction (Scheme 2). Initial

Continuous-flow retro-Diels–Alder reaction: an efficient method for the preparation of pyrimidinone derivatives

• Imane Nekkaa,
• Márta Palkó,
• István M. Mándity and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2018, 14, 318–324, doi:10.3762/bjoc.14.20

• syntheses of various pyrimidinones as potentially bioactive products by means of the highly controlled continuous-flow retro-Diels–Alder reaction of condensed pyrimidinone derivatives are presented. Noteworthy, the use of this approach allowed us to rapidly screen a selection of conditions and quickly

• antibiotics [41]. Our aim in the present study was to synthesize functionalized pyrimidinone systems through rDA reactions. Many of these products are of high importance in drug design due to their diverse biological properties including antimicrobial, antiviral, antioxidant and antitumor activities. In

• , by less harmful, environmentally benign solvents such as toluene, MeCN, methanol, and ethanol. In summary, we have developed a simple flow-based method for the preparation of pyrimidinone derivatives, precursors of a series of pharmacologically active materials, through the rDA reaction. The design

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• ]pyrimidines 110 which were later on converted to fluoroalkyl pyrazolo[1,5-a]pyrimidines 112 by treatment with deoxofluor. Marjani et al. [88] have described the synthesis of pyrazolo[1,5-a]pyrimidine 116 and 4,7-dihydropyrazolo[1,5-a]pyrimidinone derivatives 117 by condensing 4-cyano/carboxylate-5

• (5H)-one derivatives 204 by refluxing in 1 N sodium hydroxide. Pyrazolo[3,4-d]pyrimidinone 204 were further chlorinated by phosphorus oxychloride and subsequently converted to carboxylic esters 207 via cyanation followed by hydrolysis and esterification. Kaplan et al. [20] explored the synthesis of

Regiochemistry of cyclocondensation reactions in the synthesis of polyazaheterocycles

• Patrick T. Campos,
• Leticia V. Rodrigues,
• Andrei L. Belladona,
• Caroline R. Bender,
• Juliana S. Bitencurt,
• Fernanda A. Rosa,
• Davi F. Back,
• Helio G. Bonacorso,
• Nilo Zanatta,
• Clarissa P. Frizzo and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 257–266, doi:10.3762/bjoc.13.29

• ] and aromatic amidines resulted in glyoxalate-substituted pyrido[1,2-a]pyrimidinone, thiazolo[3,2-a]pyrimidinone and pyrimido[1,2-a]benzimidazole. Pyrazinones and quinoxalinones were obtained through the reaction of these glyoxalates with ethylenediamine and 1,2-phenylenediamine derivatives. On the

• intermediates, and from these data it was possible to explain the regiochemistry of the products obtained. Additionally, the data were a useful tool for elucidating the reaction mechanisms. Keywords: DFT-B3LYP; polyazaheterocycles; pyrazinone; pyrido[1,2-a]pyrimidinone; pyrimido[1,2-a]benzimidazole

• ; quinoxalinone; thiazolo[3,2-a]pyrimidinone; Introduction Various syntheses of polyazaheterocycles are described in the literature because they are important components for the preparation of bioactive molecules [1][2][3]. One of the most important synthetic methods towards compounds containing nitrogen atoms

A convenient four-component one-pot strategy toward the synthesis of pyrazolo[3,4-d]pyrimidines

• Mingxing Liu,
• Jiarong Li,
• Hongxin Chai,
• Kai Zhang,
• Deli Yang,
• Qi Zhang and
• Daxin Shi

Beilstein J. Org. Chem. 2015, 11, 2125–2131, doi:10.3762/bjoc.11.229

• catalyst (Table 1, entries 1 and 2). Sodium hydroxide could catalyze this reaction, but pyrazolo[3,4-d]pyrimidinone 5aa was obtained instead of pyrazolo[3,4-d]pyrimidine 5a (Table 1, entry 3). This shows that the catalytic properties of sodium hydroxide have some limitations. Fortunately, some strong bases

Supramolecular chemistry: from aromatic foldamers to solution-phase supramolecular organic frameworks

• Zhan-Ting Li

Beilstein J. Org. Chem. 2015, 11, 2057–2071, doi:10.3762/bjoc.11.222

• . Thus, I prepared compound 9, which bore a pyrene unit [17] (Scheme 4), based on previously published research by Sijbesma and co-workers, who had taken advantage of the excimer signal of the pyrene dimer to evaluate the stability of their famous quadruple hydrogen bonded 2-ureido-4[1H]-pyrimidinone

Syntheses of ¹⁵N-labeled pre-queuosine nucleobase derivatives

• Jasmin Levic and
• Ronald Micura

Beilstein J. Org. Chem. 2014, 10, 1914–1918, doi:10.3762/bjoc.10.199

• addition of the same pyrimidinone to the nitroolefin 2-[(2E)-3-nitroprop-2-en-1-yl]-1H-isoindole-1,3(2H)-dione [13], however, this route seemed inconvenient for our purposes because access to the nitroolefin requires several additional steps. Results and Discussion Our aim was to develop a robust synthetic