Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• processes. Cyanins have been shown to effectively initiate radical polymerization under visible light through mechanisms such as borate oxidation [61] and 1,3,5-triazine reduction [62]. More recently, cyanin dyes have enabled the reduction of iodonium salts under NIR excitation [63][64]. These preliminary

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• corresponding thiol [35][36][37][38], in the nucleophilic substitution reaction in the aromatic ring of catechol [39][40] or under electrochemical conditions [41][42][43]. An anodic activation of catechols in the presence of a thiol leads to S-functionalized catechols with triazole, triazine, pyrimidine

Tandem diazotization/cyclization approach for the synthesis of a fused 1,2,3-triazinone-furazan/furoxan heterocyclic system

• Yuri A. Sidunets,
• Valeriya G. Melekhina and
• Leonid L. Fershtat

Beilstein J. Org. Chem. 2024, 20, 2342–2348, doi:10.3762/bjoc.20.200

• agents contain a 1,2,3-triazine ring [37][38][39]. The structures of some bioactive 1,2,3-triazin-4-one derivatives are shown in Figure 1. Hence, one can assume that molecular hybridization of the 1,2,3-triazin-4-one moiety with the 1,2,5-oxadiazole core can lead to a significant modification of the

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

New triazinephosphonate dopants for Nafion proton exchange membranes (PEM)

• Fátima C. Teixeira,
• António P. S. Teixeira and
• C. M. Rangel

Beilstein J. Org. Chem. 2024, 20, 1623–1634, doi:10.3762/bjoc.20.145

• N115, in the same experimental conditions. The Nafion-doped membrane with compound TP2 with a 1.0 wt % loading showed the highest proton conductivity with 84 mS·cm−1. Keywords: electrolyser; fuel cells; Nafion-modified membranes; phosphonates; proton exchange membranes; triazine; Introduction

• -triazine isomers [30]. There have been reported several and diverse applications to a large number of compounds with a triazine moiety, ranging from biological applications [31][32][33][34], such as fungicide, herbicide, antiviral, antimicrobial, antitumor, to their use in organic synthesis, including

• combinatorial chemistry [35], in analytical chemistry, in electrochemical redox processes, in crystal engineering, and as fluorescent, light emitting, corrosion inhibitors or several other materials [36][37][38][39][40][41][42]. The most used triazine is 1,3,5-triazine (or s-triazine) that can provide

Synthesis of substituted triazole–pyrazole hybrids using triazenylpyrazole precursors

• Simone Gräßle,
• Laura Holzhauer,
• Nicolai Wippert,
• Olaf Fuhr,
• Martin Nieger,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2024, 20, 1396–1404, doi:10.3762/bjoc.20.121

• , presumably due to the increased stability of isomer 18 towards acids. This corresponds with the results for the previously reported triazene cleavage to diazonium intermediates and subsequent cyclization to triazine derivatives [3]. In the next step, the obtained pyrazolyl azides were reacted with different

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116

• efficiency, affording 3fa in 71% yield. Some heteroaryl chlorides including triazine, pyrimidine, and pyridazine skeletons were also effectively coupled with methyl acrylate to provide the desired products in good yields (3ga–ja). While unsubstituted chlorobenzene and bromobenzene were completely inert in

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• device fabrication with the electron acceptor C60. Subsequently, the design was extended to “ditopic” systems with diverse HB-capable units such as PH, 2,4-diamino-1,3,5-triazine (DAT), and barbiturate (B) that can form trimeric and hexameric “rosettes”, respectively [16]. The Sokolowski and Głowacki

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• hexahydro-1,3,5-trinitro-1,3,5-triazine (commonly called RDX), octogen (HMX), and hexanitrohexaazaisowurtzitane (CL-20) are compounds found in military grade explosives and propellants. Contamination of these cyclic nitramines in soil and groundwater is concerning due to their toxicity and potential

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• demonstrated that 1,1,1,4,4,4-hexafluorobut-2-ene reacts with dithietane, sulfur and KF with the formation of the corresponding 1,3-dithiole [16]. Also, a recent patent presents a method for the preparation of 5,6-bis(trifluoromethyl)-1,2,4-triazine-3-carboxylic acid ethyl ester starting from 1,1,1,4,4,4

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

• Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

• ] (Scheme 12a). Meanwhile, the Jasiński group turned their attention to the [3 + 3] cycloaddition of α-amino esters and trifluoromethylated hydrazonoyl halides and demonstrated the efficient synthesis of trifluoromethylated 1,2,4-triazine derivatives [80] (Scheme 12b). Difluoromethylated compounds play an

• trifluoromethylated hydrazonoyl halides. [3 + 2]/[3 + 3] Cycloadditions of trifluoromethylated hydrazonoyl halides. Substrate scope for [3 + 2] cycloadditions with trifluoroacetonitrile imines reported by Jasiński’s team and other groups. Synthesis of trifluoromethylated 1,2,4-triazole and 1,2,4-triazine derivatives

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• esters are also suitable substrates for the reaction. In this case hydrolysis and thiazole ring expansion were accompanied with the change of the thiazolotriazine junction type from thiazolo[3,2-b][1,2,4]triazine to thiazino[2,3-c][1,2,4]triazine. Keywords: N,S-heterocycles; ring expansion; skeletal

• closely related hybrid compounds including fragments of 1,3-thiazine and imidazo-1,2,4-triazine is still highly relevant. Earlier we have demonstrated that imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazines and their derivatives functionalized at position 6 are capable of undergoing skeletal rearrangements and

• derivatives undergo rearrangement into the corresponding isomeric derivatives of imidazo[4,5-e]thiazolo[2,3-c]-1,2,4-triazine [18][21] (Scheme 1A). In the present study, we report a new base-induced recyclization of functionalized imidazothiazolotriazines 1 and 2 resulting in derivatives of the new

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• such techniques are beneficial not only from a green chemistry perspective [11], but they also afford conditions conducive to new reactivities and the development of novel materials [9]. Previously, we have explored the synthesis of phosphorus-bridged g-CN-type materials produced from a triazine unit

• and found that the resulting material featured good photochemical properties (Scheme 1) [38]. Yet, conventional g-CN materials are not based on triazine units, but rather on heptazine ones, thus featuring more open structures. In an effort to replicate a structure closer to known g-CN systems, we

• -based materials showed similar resonances to previous work by our group on phosphorus-linked triazine networks [38]. The 31P MAS NMR of g-h-PCN showed a broad resonance centered around −8.9 ppm, with a sharp residual phosphate resonance at 0.9 ppm (Figure 3a). NMR analysis of similar materials, by our

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• -based photoabsorption and fluorescence bands of OTK-2 appear in a shorter wavelength region than those of the corresponding (D–π)2A-type fluorescent dye having an azine ring (pyridine, pyrazine or triazine ring) as a substitute for the phenyl ring. However, the molar extinction coefficient (εmax) and

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

• such as triazine, diazines or aromatics containing cyano and sulfone groups are popular acceptor units for the construction of highly efficient TADF emitters [8][9][10][11]. Pyrimidine (1,3-diazine) owing to its aromaticity, significant π-deficiency, strong electron affinity, high luminous efficiency

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• accommodated in the cavity of A through π–π stacking interactions between the naphthalene ring of 3 and a triazine ligand of A from the X-ray crystallographic analysis. In the control experiment, without host A, only 44% yield of the conventional 9,10-adduct 4 was produced without any 1,4-adduct product

• reaction, the anthracene moiety stacks onto the planar triazine of B through π–π stacking and possible charge-transfer interaction between each other, which stabilizes the complex. However, after the reaction, the framework of the product is bent at the 9,10-position, which undermines the host–guest

Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions

• Jun-Xian Gou,
• Yang Luo,
• Xi-Nan Yang,
• Wei Zhang,
• Ji-Hong Lu,
• Zhu Tao and
• Xin Xiao

Beilstein J. Org. Chem. 2021, 17, 2950–2958, doi:10.3762/bjoc.17.204

• to yield different metal-organic frameworks [6][7][8][9][10][11], but also can be used as analytical reagents for the detection of different organic and inorganic substances [12][13][14]. Among the various central molecules for the synthesis of Schiff bases, melamine (2,4,6-triamino-s-triazine) has

• electropositivity can be a perfect candidate for the study of outer-surface interaction of cucurbit[n]urils [21][22][23][24]. In this work, nitrogen-rich melamine is used as the center molecule to synthesize the Schiff base 2,4,6-tris(((4-(4-carboxybutyl)phenyl)methylene)amino)-1,3,5-triazine (TBT) through the

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

• Ettore Crovini,
• Zhen Zhang,
• Yu Kusakabe,
• Yongxia Ren,
• Yoshimasa Wada,
• Bilal A. Naqvi,
• Prakhar Sahay,
• Tomas Matulaitis,
• Stefan Diesing,
• Ifor D. W. Samuel,
• Wolfgang Brütting,
• Katsuaki Suzuki,
• Hironori Kaji,
• Stefan Bräse and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

• %, with Commission Internationale de l’Éclairage coordinate of (0.22, 0.47), at 1 mA cm−2. Keywords: blue emitters; dimer; indolocarbazole; orientation; outcoupling effect; solution-processed OLEDs; TADF emitters; triazine; Introduction Organic thermally activated delayed fluorescence (TADF) materials

• eV for DICzTRZ vs −1.75 eV for ICzTRZ) since the electronic environment surrounding the t-Bu-triazine remains essentially unperturbed (Figure 3). Optoelectronic properties The electrochemical properties of the two materials were studied in degassed DCM with tetra-n-butylammonium hexafluorophosphate

• transitions was also evaluated by analysis of the natural transition orbitals (NTOs) (see Supporting Information File 1, Table S2). The T1 and T2 HONTO and LUNTO (highest occupied and lowest unoccupied natural Transition orbitals) are localized on the central diindolocarbazole and adjacent triazine

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

Synthesis of new pyrazolo[1,2,3]triazines by cyclative cleavage of pyrazolyltriazenes

• Nicolai Wippert,
• Martin Nieger,
• Claudine Herlan,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2021, 17, 2773–2780, doi:10.3762/bjoc.17.187

• [3,4-d][1,2,3]triazine core with commercially available building blocks, enabling the extension of the protocol to gain other derivatives straightforwardly. Attempts to synthesize 3,7-substituted-4,7-dihydro-3H-pyrazolo[3,4-d][1,2,3]triazines, the regioisomers of the successfully gained 3,6-substituted

• -methylamide-substituted aryltriazenes 7 could be efficiently converted into 3,4-dihydrobenzo[d][1,2,3]triazine derivatives 8 [37] (Scheme 2). In this context, triazenes have shown beneficial properties as they can be used as protected diazonium species which can be handled and converted in various

• transformations without decomposition [37][38][39]. In the herein presented study, we apply the cyclative cleavage reaction to pyrazolyltriazenes instead of aryltriazenes, which results in the synthesis of diverse pyrazolo[3,4-d][1,2,3]-3H-triazine derivatives 5. Results and Discussion According to the literature

Photoinduced post-modification of graphitic carbon nitride-embedded hydrogels: synthesis of 'hydrophobic hydrogels' and pore substructuring

• Cansu Esen and
• Baris Kumru

Beilstein J. Org. Chem. 2021, 17, 1323–1334, doi:10.3762/bjoc.17.92

• -sustainable semiconductors are slowly being replaced by a new generation of semiconductors. Graphitic carbon nitride (g-CN) is a metal-free polymeric semiconductor that is mainly composed of carbon and nitrogen elements by tri-s-triazine, triazine imide, or heptazine repeating units [16][17][18]. g-CN

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

• -triazine-3-thiones with acetylenedicarboxylic acid dimethyl and diethyl esters (DMAD and DEAD) and subsequent base-catalyzed rearrangement of the obtained imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazines into regioisomeric imidazo[4,5-e]thiazolo[2,3-c]-1,2,4-triazine derivatives. Keywords: amidine

• rearrangement; cyclocondensation; heterocycles; thiazolidine-4-one; 1,2,4-triazine; Introduction The thiazolidin-4-one heterocyclic system is a well-known, accessible and, as a consequence, a widely used pharmacophore in the chemistry of biologically active compounds possessing antimicrobial [1

• only products, namely, thiazolo[3,2-b]-1,2,4-triazines 2 (Scheme 1) while the regioisomeric thiazolo[2,3-с]-1,2,4-triazine derivatives remain unavailable. The present work is devoted to the development of methods for the regiodirected synthesis of two series of functionalized imidazothiazolotriazines

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

• production of biodiesel [5][80], intermediates for triazine synthesis [48], etc. Some derivatives were grafted onto polystyrene resins for catalytic uses [5]. Various solvents and temperatures were used such as hot DMF [5], neat [79], toluene or hexane at 25–100 °C [79]. Generally, higher temperatures seem

• equivalents of the carbodiimide in the reaction with N,N’-disubstituted guanidines resulted in the formation of 1,2-dihydro-1,3,5-triazine derivatives as the main products of the cycloaddition reaction [82]. They also showed that increasing the amount of the carbodiimide to 3 equivalents led to excellent

• triazine yields in refluxing THF (Scheme 42). The mechanism of this reaction proceeds via the formation of a nonisolated triguanide intermediate, that spontaneously cyclizes to the 1,3,5-triazine derivative after elimination of the amine counterpart (Scheme 43). The authors proposed two plausible

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

• 115, could be only obtained. The regioisomer A being less stable due to steric hindrance between the amino and the aryl group rearranges to give desired product 115. The mechanism involved in the formation of intermediate B is similar to the mechanism proposed for amino-1,3,5-triazine ring

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

• in good to excellent yield. The protocol conforms to the characteristics of green and environmental conservation, having a reaction time of only 1 hour, achieving the purpose of saving energy. In 2019, Liang and colleagues [24] reported a method for preparing perfluoroalkyl-s-triazine via visible

• -light-promoted [5 + 1] cyclization initiated by an EDA complex. Perfluoroalkyl-s-triazine derivative 45 was synthesized by the reaction of biguanidine derivative 44 and perfluoroalkyl iodide 28 in the presence of sodium hydroxide (Scheme 15). Considering that oxygen played an indispensable role in the

• process, the authors supposed that it may facilitate single-electron transfer between biguanidine anion and perfluoroalkyl halide. By constructing two C–N bonds at the same time, the triazine heterocyclic structure that is commonly utilized in medical and material fields was accomplished by [5 + 1