Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• structure and reactivity of the obtained macrocycle are outlined. Keywords: amidrazones; hexaazamacrocycles; pyrazolo[3,4-d]pyrimidines; ring contraction; self-assembly; Introduction The chemistry of polyazamacrocycles (PAMs) is currently one of the most rapidly developing areas of heterocyclic chemistry

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Mikhail E. Minyaev and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• method for the synthesis of pyrimidines containing an allomaltol unit. The suggested approach is based on the reaction of 2-(1-(dimethylamino)-3-oxo-3-arylprop-1-en-2-yl)-3-hydroxy-6-methyl-4H-pyran-4-ones with cyanamide. The photochemical behavior of the obtained pyrimidines was investigated. It was

• [h]pyrano[2,3-f]quinazolines were confirmed by X-ray diffraction analysis. Based on the performed studies, a two-stage telescopic method for the synthesis of polyaromatic benzo[h]pyrano[2,3-f]quinazolines including the initial photocyclization of the starting pyrimidines and the final dehydration was

• proposed. Keywords: allomaltol; dihydrobenzo[h]pyrano[2,3-f]quinazolines; 6π-electrocyclization; photocyclization; pyrimidines; Introduction Photochemical processes involve absorption of UV light leading to the generation of molecules in the excited state and subsequent chemical transformations [1][2

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• Scholl reaction conditions (DDQ, H+; or FeCl3, CH3NO2), the aza-[5]helicenes 22 and 24 were obtained respectively with 60% and 23% yields [38]. It was noted that with the installation of two adjacent pyrimidines in this hexarylbenzene precursor, a fully cyclized planar NG was formed toward Scholl

A new route for the synthesis of 1-deazaguanine and 1-deazahypoxanthine

• Raphael Bereiter,
• Marco Oberlechner and
• Ronald Micura

Beilstein J. Org. Chem. 2022, 18, 1617–1624, doi:10.3762/bjoc.18.172

• pyrrolopyrimidines) are N-heterocycles that have become an indispensable part of research in medicinal chemistry [1][2][3]. Especially, derivatives of 3-deazaguanine (imidazo[4,5-c]pyridines) [4], 7-deazaguanine/-hypoxanthine (pyrrolo[2,3-d]pyrimidines) [5][6], and 9-deazaguanine/-hypoxanthine (pyrrolo[3,2-d

• ]-pyrimidines) [7][8][9] have been in the center of attention and were found to be effective compounds for the inhibition of various molecular targets associated with dysfunction of the central nervous system (e.g., as GABA and serotonin receptor modulators, or as inhibitors of phosphodiesterase PDE10A

Ferrocenoyl-adenines: substituent effects on regioselective acylation

• Mateja Toma,
• Gabrijel Zubčić,
• Jasmina Lapić,
• Senka Djaković,
• Davor Šakić and
• Valerije Vrček

Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133

• procedures for preparing N-ferocenoylated pyrimidines were tested earlier [19][23], and the reaction of nucleobase with (chlorocarbonyl)ferrocene (or ferrocenoyl chloride, FcCOCl) under basic conditions appeared as a simple and optimal method for the synthesis [24]. Herewith, we demonstrate that substituents

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

• interact with all HDAC isoforms of groups I, II, and IV. Thus, efforts are currently underway to synthesize inhibitors selective for certain HDAC isoforms [2]. On the other hand, pyrimidines represent an important group of heterocyclic compounds exhibiting a broad spectrum of biological activity [16][17

Copper-catalyzed multicomponent reactions for the efficient synthesis of diverse spirotetrahydrocarbazoles

• Shao-Cong Zhan,
• Ren-Jie Fang,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2022, 18, 796–808, doi:10.3762/bjoc.18.80

• [carbazole-2,3'-indolines], spiro[carbazole-3,5'-pyrimidines] and spiro[carbazole-3,1'-cycloalkanes] in satisfactory yields and with high diastereoselectivity. Keywords: Diels–Alder reaction; indole; indolo-2,3-quinodimethane; Levy reaction; tetrahydrocarbazole; spirooxindole; Introduction

• compound 3a (CCDC 2109578) and 4e (CCDC 2109579) were successfully determined by X-ray diffraction. It is pleased to find that the obtained spiro[carbazole-3,5'-pyrimidines] 4a–h have same cis-configuration to that of the above prepared spiro[carbazole-3,3'-indolines] 1a–j and spiro[carbazole-2,3

• sustainable, general and practical, which providing facile access to important polysubstituted spiro[carbazole-3,3'-indolines], spiro[carbazole-2,3'-indolines], spiro[carbazole-3,5'-pyrimidines] and spiro[carbazole-3,1'-cycloalkanes] with good yields and high diastereoselectivity. This reaction actually

Syntheses of novel pyridine-based low-molecular-weight luminogens possessing aggregation-induced emission enhancement (AIEE) properties

• Masayori Hagimori,
• Tatsusada Yoshida,
• Yasuhisa Nishimura,
• Yukiko Ogawa and
• Keitaro Tanaka

Beilstein J. Org. Chem. 2022, 18, 580–587, doi:10.3762/bjoc.18.60

• . pyrido[1,2-a]pyrrolo[3,4-d]pyrimidines 3a,b and N-methyl-4-((pyridin-2-yl)amino)maleimides 4a–e, were selectively prepared by a one-pot reaction between a functionalized maleimide and 2-aminopyridines with electron-donating or electron-withdrawing groups at position 5 and were investigated

• heterocyclic compounds, such as ring-fused pyridines (pyrido[1,2-a]pyrrolo[3,4-d]pyrimidines) and secondary aminopyridines (N-methyl-4-((pyridin-2-yl)amino)-substituted maleimides), by changing the substituents at position 5 of the 2-aminopyridine. Interestingly, among these pyridine derivatives, secondary

• aminopyridines based on the acceptor–donor–acceptor (A–D–A) system exhibit AIEE properties in aqueous media, which may be novel candidate molecules for AIEE. Herein, we report the synthesis, photophysical properties, and computational studies of pyrido[1,2-a]pyrrolo[3,4-d]pyrimidines and N-methyl-4-((pyridin-2

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• achieving efficient deep-blue emission, we were interested to study the influence of substituents in position 2 of the pyrimidine ring on the TADF properties of pyrimidine–carbazole emitters. For this purpose, we performed the synthesis of novel 4,6-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)pyrimidines

• (I) 3-methylsalicylate (CuMeSal), and Cs2CO3 as a catalyst system furnished the corresponding 2-substituted pyrimidines 2a–d. For the introduction of cyano and 4-(tert-butyl)phenylthio groups into position 2 of the pyrimidine, the conversion of the methylthio group to the better leaving

• from 0.34–0.49, was estimated for compounds with CN, SCH3, and SO2CH3 functional groups at the position 2 of the pyrimidine unit. We believe that our findings on the TADF properties of differently substituted carbazole–pyrimidines will be useful for molecular design of high-performance TADF emitters in

Synthesis of novel [1,2,4]triazolo[1,5-b][1,2,4,5]tetrazines and investigation of their fungistatic activity

• Anna V. Korotina,
• Svetlana G. Tolshchina,
• Rashida I. Ishmetova,
• Natalya P. Evstigneeva,
• Natalya A. Gerasimova,
• Natalya V. Zilberberg,
• Nikolay V. Kungurov,
• Gennady L. Rusinov,
• Oleg N. Chupakhin and
• Valery N. Charushin

Beilstein J. Org. Chem. 2022, 18, 243–250, doi:10.3762/bjoc.18.29

• particular, imidazo[1,2-a]pyridines and imidazo[1,2-a]pyrimidines exhibit a wide spectrum of biological activity, including antiviral and antibacterial ones [1][2]. A promising approach for the development of new drugs is the synthesis and bioscreening of high nitrogen-containing azoloazines, including azolo

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• of various nucleobase derivatives, oxathiolane acetate 20a was further condensed with various pyrimidines (Scheme 34) and purines (Scheme 35), as reported by Jeong et al. [73]. When X = F, the cytosine derivative 87, among all of these nucleosides having anti-HIV activity, was found to be the most

Synthesis of O⁶-alkylated preQ₁ derivatives

• Laurin Flemmich,
• Sarah Moreno and
• Ronald Micura

Beilstein J. Org. Chem. 2021, 17, 2295–2301, doi:10.3762/bjoc.17.147

• ]pyrimidines starting from readily accessible N2-pivaloyl-protected 6-chloro-7-cyano-7-deazaguanine. Substitution of the 6-chloro atom with the alcoholate of interest proceeds straightforward. The transformation of the 7-cyano substituent into the required aminomethyl group turned out to be challenging and was

Cationic oligonucleotide derivatives and conjugates: A favorable approach for enhanced DNA and RNA targeting oligonucleotides

• Mathias B. Danielsen and
• Jesper Wengel

Beilstein J. Org. Chem. 2021, 17, 1828–1848, doi:10.3762/bjoc.17.125

• monomer has been used [27]. The reactivity of the above-mentioned chemical groups has enabled the attachment of various amine-functionalized groups onto the 5-position of pyrimidines via both the modified monomeric building blocks and post-synthetic ON chemistry [27][28][31][32][33][34][35][36][37][38][39

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

• suggesting that Io4 may be a promising alternative to T where stronger binding is desired [108]. PNA nucleobases for Hoogsteen recognition of pyrimidines: Triple helix formation, especially using tailored oligonucleotide analogues as PNA, could be a general and sequence specific approach for molecular

• recognition of pyrimidines in hypothetical X•T–A or X•C–G triplets is complicated by two problems: 1) pyrimidines present only one hydrogen bond acceptor (C=O in T or U) or donor (-NH2 in C) in the major groove, and 2) the six-membered pyrimidine ring extends further out in the major groove than the five

• -membered ring of purines causing a steric clash with the incoming third nucleobase. In other words, the Hoogsteen face of Watson–Crick base pairs in the major groove is not isomorphous providing more space and better hydrogen bonding options for purines than for pyrimidines. Despite significant efforts by

Synthesis of functionalized imidazo[4,5-e]thiazolo[3,2-b]triazines by condensation of imidazo[4,5-e]triazinethiones with DMAD or DEAD and rearrangement to imidazo[4,5-e]thiazolo[2,3-c]triazines

• Alexei N. Izmest’ev,
• Dmitry B. Vinogradov,
• Natalya G. Kolotyrkina,
• Angelina N. Kravchenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2021, 17, 1141–1148, doi:10.3762/bjoc.17.87

• ], antituberculosis [2], anti-inflammatory [3][4], anticancer [5], antidiabetic [6][7], and antiviral activities [8]. A significant number of biologically active thiazolidines amount to their heteroannelated derivatives, namely, condensed thiazolo[3,2-a]pyrimidines [9] and thiazolo[3,2-b]-1,2,4-triazoles [10], as

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• ], superbases [6], and as ligands for metal complexation [7]. In organic synthesis, biguanides are precursors to several heterocycles [1] such as 1,3,5-triazines, pyrimidines, boron heterocycles, and benzo[f]quinazolines. The application of biguanides as catalysts has been reported mostly for the

Beyond ribose and phosphate: Selected nucleic acid modifications for structure–function investigations and therapeutic applications

• Christopher Liczner,
• Kieran Duke,
• Gabrielle Juneau,
• Martin Egli and
• Christopher J. Wilds

Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76

• destabilization of the duplex, prompting its development. The synthesis of 2'-O-MOE-modified ribonucleosides was first described in 1995 [116]. Since then, two practical strategies have been developed for synthesizing 2'-O-MOE ribonucleosides. For pyrimidines, this involves treating 2,2'-anhydrouridine with

• -Arabinonucleosides of pyrimidines can be prepared from 2,2'-anydronucleosides [174] and purines from approaches which include condensation of the nucleobase with 2,3,5-tri-O-benzyl-ᴅ-arabinofuranosyl chloride [175]. The 2'-fluoro-β-ᴅ-arabinofuranose nucleosides can be prepared by coupling of the nucleobase with 3,5

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

• phenanthroline. 6 Pyrimidines/fused pyrimidines 6.1 Pyrimidines Pyrimidines are six-membered aromatic heterocycles containing two nitrogen atoms at positions 1 and 3. These are an important class of compounds depicting a wide range of biological activities such as COX inhibitors, anti-inflammatory, anticancer

• 78 (Scheme 29). 6.2 Fused pyrimidines Fused pyrimidines represent an important class of heterocycles with potential biological activities such as antidiabetic (79), antiviral (80), anti-inflammatory (81, 82), anticancer (83), antibacterial (84) and antiplatelet (85) [75][76][77][78][79] with an

• advantage of the synergistic action of the two pharmacophores fused (Figure 7). 6.2.1 Pyrrolo[2,3-d]pyrimidines: Bhuyan and co-workers [80] reported an efficient MWA three-component reaction between N,N-disubstituted-6-aminouracil 86, arylglyoxal monohydrate 33, and amines 32 in AcOH resulting in the

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• -bond adduct. The first light-promoted three-component reaction has been realized by a halogen-bond adduct, forming perfluoroalkylated pyrimidines 26 (Scheme 8). A variety of perfluorinated chains were assembled with methylene compounds and guanidines or amidines, giving the corresponding

• perfluoroalkylated pyrimidines in good to excellent yield. In 2017, Chen and colleagues [34] prepared the phenanthridine derivative 29 with CFL (25 W) irradiation of a solution containing 27, perfluoroalkyl iodide 28, amine additive N,N,N´,N´-tetraethylethylenediamine (TEEDA) in THF (Scheme 9). TEEDA and

• perfluoroalkylated pyrimidines 26 initiated by an EDA complex. Synthesis of phenanthridine derivative 29 initiated by an EDA complex. Synthesis of cis-tetrahydroquinoline derivative 32 initiated by an EDA complex. Mechanism of the synthesis of cis-tetrahydroquinoline derivative 32. Synthesis of phenanthridine

1,2,3-Triazoles as leaving groups: S_NAr reactions of 2,6-bistriazolylpurines with O- and C-nucleophiles

• Dace Cīrule,
• Irina Novosjolova,
• Ērika Bizdēna and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 410–419, doi:10.3762/bjoc.17.37

• deprotonated acetylacetone and diphenylmethane. Even there are reports on SNAr reactions of acetylacetone with purines and pyrimidines [56][80], in our hands only polymerization of acetylacetone was observed. On the other hand, the diphenylmethane anion (pKa 32; DMSO [81]) apparently is too basic and

Facile preparation and conversion of 4,4,4-trifluorobut-2-yn-1-ones to aromatic and heteroaromatic compounds

• Takashi Yamazaki,
• Yoh Nakajima,
• Minato Iida and
• Tomoko Kawasaki-Takasuka

Beilstein J. Org. Chem. 2021, 17, 132–138, doi:10.3762/bjoc.17.14

• -ones by the oxidation of the readily accessible corresponding propargylic alcohols as well as their utilization as Michael acceptors for the construction of aromatic and heteroaromatic compounds are reported. Keywords: CF3-containing propargylic alcohols; CF3-containing ynones; oxidation; pyrimidines

• -(trifluoromethyl)pyrimidines (N-nucleophiles), both in a concise fashion, with the full details, including the preparation of 2, being reported herein. Results and Discussion Investigations on the reaction conditions were carried out for the oxidation of propargylic alcohols 1, which were readily accessible by our

• 6aa [37][38][39][40] and 6ba [37][38][41][42], it is noteworthy to realize the construction of relatively rare pyrimidines in a concise fashion via the ynones 2 with a CF3 group. Conclusion As described above, we succeeded in the construction of 4,4,4-trifluorobut-2-yn-1-ones 2 by way of a convenient

Chan–Evans–Lam N1-(het)arylation and N1-alkеnylation of 4-fluoroalkylpyrimidin-2(1H)-ones

• Viktor M. Tkachuk,
• Oleh O. Lukianov,
• Mykhailo V. Vovk,
• Isabelle Gillaizeau and
• Volodymyr A. Sukach

Beilstein J. Org. Chem. 2020, 16, 2304–2313, doi:10.3762/bjoc.16.191

• corresponding pyrimidines. An efficient C–N bond-forming process is also observed by using boronic acid pinacol esters as coupling partners in the presence of Cu(II) acetate and boric acid. The 4-fluoroalkyl group on the pyrimidine ring significantly assists in the formation of the target N1-substituted

Synthesis of 3(2)-phosphonylated thiazolo[3,2-a]oxopyrimidines

• Ksenia I. Kaskevich,
• Anastasia A. Babushkina,
• Vladislav V. Gurzhiy,
• Dmitrij M. Egorov,
• Nataly I. Svintsitskaya and
• Albina V. Dogadina

Beilstein J. Org. Chem. 2020, 16, 1947–1954, doi:10.3762/bjoc.16.161

• , which could be used as an additional approach to estimate the regioselectivity of the reaction. A single example of the use of 13C NMR spectroscopy for unambiguous establishing the structure of thiazolo[3,2-a]pyrimidines obtained was given by Iranian researchers [36], but only for the 5-oxo isomers. In

Regiodivergent synthesis of functionalized pyrimidines and imidazoles through phenacyl azides in deep eutectic solvents

• Paola Vitale,
• Luciana Cicco,
• Ilaria Cellamare,
• Filippo M. Perna,
• Antonio Salomone and
• Vito Capriati

Beilstein J. Org. Chem. 2020, 16, 1915–1923, doi:10.3762/bjoc.16.158

• °C) in the presence or absence of bases (Et3N). Keywords: deep eutectic solvents; imidazoles; phenacyl azides; phenacyl halides; pyrimidines; Introduction In a world with dwindling petroleum resources, the setting up of more and more sustainable routes for the preparation of heterocyclic compounds

• place smoothly using such neoteric solvents (Scheme 1, path a) [16]. Among nitrogen-containing heterocyles, imidazoles and pyrimidines are important structural scaffolds commonly found in natural products [17][18], light-emitting devices [19][20], and pharmacologically active compounds as anticancer

• intramolecular nucleophilic attack to the terminal imino group of 9a, provides cyclized adduct 10a, and finally pyrimidine derivative 7a by aromatization/elimination of NH3. To the best of our knowledge, this is the first one-pot synthesis of functionalized pyrimidines using phenacyl azides as the sole starting