Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• nucleophiles compared to organometallic or metal phosphides generated through metalation processes. Hayashi et al. [66] used tris(trimethylsilyl)phosphine to control the nucleophilic substitution in the preparation of P,N-(phosphino)triazine ligands (Scheme 5). It was shown that the use of other nucleophiles

• and/or alkoxy derivatives 29–31. Selectively varying the molar ratio of the silylphosphine nucleophile and the starting reagent 25 resulted in the corresponding bis- and tris(diphenylphosphine)triazine motifs 27 and 28. A subsequent nucleophilic substitution reaction of 27 gave compounds 32 and 33

• of pyridylphosphine ligands. Synthesis of piperidyl- and oxazinylphosphine ligands. Synthesis of linear multi-chelate pyridylphosphine ligands. Synthesis of chiral acetal pyridylphosphine ligands. Synthesis of diphenylphosphine-substituted triazine ligands. Synthesis of (pyridine-2-ylmethyl)phosphine

Synthesis, photophysical and electrochemical properties of pyridine, pyrazine and triazine-based (D–π–)₂A fluorescent dyes

• Keiichi Imato,
• Toshiaki Enoki,
• Koji Uenaka and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2019, 15, 1712–1721, doi:10.3762/bjoc.15.167

• and OUJ-2 with two (diphenylamino)carbazole thiophene units as D (electron-donating group)–π (π-conjugated bridge) moiety and a pyridine, pyrazine or triazine ring as electron-withdrawing group (electron-accepting group, A) have been designed and synthesized. The photophysical and electrochemical

• lowering of the LUMO energy level are dependent on the electron-withdrawing ability of the azine ring, which increases in the order of OUY-2 < OUK-2 < OUJ-2. Keywords: D–π–A structure; fluorescent dyes; pyrazine; pyridine; triazine; Introduction Donor–π-conjugated–acceptor (D–π–A) dyes are constructed of

• an electron-donating group (D) such as a diphenyl or dialkylamino group and an electron-withdrawing group (electron-accepting group, A) such as a nitro, cyano, and carboxy group or an azine ring such as pyridine, pyrazine and triazine linked by π-conjugated bridges such as oligoenes and heterocycles

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• iron MOFs have resulted in lesser yield than Cu-MOF. The reaction has well tolerated different substituent on the reactants except for 4-NO2; 3,4-dichlorobenzaldehyde, 2-aminopyrimidine, and 2,4,6-triamino-1,3,5-triazine which failed to give the desired product. Also, benzaldehydes substituted with

Mechanochemical Friedel–Crafts acylations

• Mateja Đud,
• Anamarija Briš,
• Iva Jušinski,
• Davor Gracin and
• Davor Margetić

Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130

• method in the synthesis of covalent triazine frameworks. Herein, we report related results on solvent-free FC acylation reactions conducted in a ball mill, which is the continuation of our program in organic mechanosynthesis [20][21][22][23][24]. Results and Discussion Mechanochemical FCR of pyrene (1

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• the formation of a Pt-based supramolecular square took more than four weeks at 100 °C. Using a similar approach, Otera’s group also demonstrated for the formation of a bowl-shaped assembly 9 in 90% yield upon grinding for 10 min 2,4,6-tri(pyridin-3-yl)-1,3,5-triazine and palladium ((en)Pd(NO3)2

A switchable [2]rotaxane with two active alkenyl groups

• Xiu-Li Zheng,
• Rong-Rong Tao,
• Rui-Rui Gu,
• Wen-Zhi Wang and
• Da-Hui Qu

Beilstein J. Org. Chem. 2018, 14, 2074–2081, doi:10.3762/bjoc.14.181

• amide reaction between compound 6 and 6-azidohexan-1-amine in the presence of 2-chloro-4,6-dimethoxy-1,3,5-triazine and N-methylmorpholine. Finally, the classical and effective “Click” reaction was used to produce the target compound [2]rotaxane R1. The crown ether 9 and dibenzylammonium ion (R2NH2

• reported. Synthesis Compound 8: The mixture of compound 6 (5.0 g, 6.83 mmol), compound 7 (2.9 g, 20.49 mmol) and 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT, 3.6 g, 20.49 mmol) was placed in a 250 mL round-bottom flask and dissolved by 100 mL methylene chloride. Then, N-methylmorpholine (NMM, 3.5 g, 34.15

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

• Cristina Morar,
• Pedro Lameiras,
• Attila Bende,
• Gabriel Katona,
• Emese Gál and
• Mircea Darabantu

Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145

• to self-organise in solution and to self-assembly in the solid state. Keywords: amination; dendrimers; melamines; nano-aggregates; 4-(n-octyloxy)aniline; Introduction N-Substituted melamine (2,4,6-triamino-1,3,5-triazine)-based dendrimers are a class of macromolecules reported as early as 2000 by E

• -triazine dendrimers exhibiting mesogenic behaviour. The first cases known so far refer to N-substituted G-0-3 dendritic melamines [19][20][21] with n-octyl peripheral groups as unconventional columnar liquid crystals and G-0 tris(triazolyl)triazines (available via the “click” reaction between 2,4,6-tris

• (ethynyl)-s-triazine and various icosanyloxyphenylazides) with liquid crystalline and luminescent properties [22]. On the other hand, mesogenic supramolecular perylene bisimide assemblies with a number of 2-amino-4,6-bis[(4-alkoxy)phenylamino]-s-triazines [23], amphiphilic azobenzene-containing linear

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

• Claudia Lar,
• Adrian Woiczechowski-Pop,
• Attila Bende,
• Ioana Georgeta Grosu,
• Natalia Miklášová,
• Elena Bogdan,
• Niculina Daniela Hădade,
• Anamaria Terec and
• Ion Grosu

Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115

• , Slovakia 10.3762/bjoc.14.115 Abstract The aromatic nucleophilic substitution reaction based synthesis of a three-armed cryptand displaying 2,4,6-triphenyl-1,3,5-triazine units as caps and pyridine rings in the bridges, along with NMR, MS and molecular modelling-based structural analysis of this compound

• titration; 1,3,5-triazine; Introduction Cryptands with C3-symmetric aromatic reference groups are exciting targets, on the one hand due to the challenges encountered in their synthesis and on the other due to their ability (macrobicyclic effect [1]) to form supramolecular assemblies with cations, anions or

• design of the cryptand by replacing the central benzene ring with a triazine unit (in which the H atoms of the ortho positions are replaced by lone electron pairs belonging to the N atoms). The resulting less sterically hindered cryptand 2 (Figure 1) was then tested for its ability to form host–guest

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

• guanidinium compound. This low basicity was suggested to be a central factor behind the catalytic activity. A clarification of the mechanism of guanidine-based catalysis has more recently been attempted by anchoring a 2,4-diamino-1,3,5-triazine core to the N3 of uracil bases of UpU by two side arms, each

• bearing a Zn2+–cyclen complex (Scheme 7) [78]. The ternary complex of Zn2+, UpU and 6a was shown to be more stable than any of the binary complexes of these species. Within this ternary complex, the triazine core could interact with the phosphodiester linkage and via various tautomeric forms facilitate

• the proton transfer between the attacking 2´-OH, non-bridging phosphate oxygen and departing 5´-O. The scaffold still was flexible enough to allow both cleavage and isomerization of the phosphodiester linkage. In the pH range 6–8, where the triazine core remained neutral (pKa = 3.96), the cleavage

Recent advances in synthetic approaches for medicinal chemistry of C-nucleosides

• Kartik Temburnikar and
• Katherine L. Seley-Radtke

Beilstein J. Org. Chem. 2018, 14, 772–785, doi:10.3762/bjoc.14.65

• pyrrolo[2,1-f]triazine C-nucleosides (GS-5734 and GS-6620) [32][63][64][65]. Thus, this review attempts to capture the progress in the synthesis efforts and subsequent drug discovery of the C-nucleosides over the past few years. In the first section, the structural and stereochemical underpinnings of

• ]triazine) C-nucleosides (Figure 7) [63][64][65][69][70][77]. The synthesis of 4-aza-7,9-dideazaadenine C-nucleoside 2 (Figure 7A) was first reported by Patil et al. [86] using a sequential approach. In contrast, scientists at Gilead treated perbenzylated ribonolactone with lithiated 4-aza-7,9

• -Me analogues of pyrrolo- and imidazo[2,1-f][1,2,4]triazine C-nucleosides using a 2'-β-Me lactone that mimic adenosine and guanosine (12–19, Figure 8) [71][72]. The adenine analogues of pyrrolo- and imidazo[2,1-f][1,2,4]triazine were active as nucleosides in HCV1b RNA replication assays, and as

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• and triazine derivatives. In this field, the contribution of the Adachi’s group is remarkable. The first report mentioning a pure blue emission with a diphenylsulfone derivative was reported in 2012 [40]. By a careful control of the π-conjugation length between the donor and the acceptor, D3-based

• -TADF white OLEDs with 16% EQE could be fabricated [30]. 4. Triazine–pyrimidine based emitters Among possible electron acceptors, another structure has been extensively regarded as an adequate electron acceptor for the design of blue TADF emitters and this structure is the triazine unit. When combined

• blue TADF emitters can be cited, the molecules differing by the strategy used to connect the donor(s) to triazine. However, contrarily to azasiline that possesses a six-membered central ring, carbazole only possesses a five-membered central ring, inducing a deviation of the two adjacent aromatic rings

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

Microfluidic radiosynthesis of [¹⁸F]FEMPT, a high affinity PET radiotracer for imaging serotonin receptors

• Thomas Lee Collier,
• Steven H. Liang,
• J. John Mann,
• Neil Vasdev and
• J. S. Dileep Kumar

Beilstein J. Org. Chem. 2017, 13, 2922–2927, doi:10.3762/bjoc.13.285

• has met with limited success. An arylpiperazine derivative of 3,5-dioxo-(2H,4H)-1,2,4-triazine radiolabeled with carbon-11 (t½ = 20.4 min), [11C]MPT, is the first successful agonist PET tracer reported for 5-HT1AR in non-human primates. The binding of [11C]MPT in baboon brain was in excellent

¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution

• Sergey L. Deev,
• Alexander S. Paramonov,
• Tatyana S. Shestakova,
• Igor A. Khalymbadzha,
• Oleg N. Chupakhin,
• Julia O. Subbotina,
• Oleg S. Eltsov,
• Pavel A. Slepukhin,
• Vladimir L. Rusinov,
• Alexander S. Arseniev and
• Zakhar O. Shenkarev

Beilstein J. Org. Chem. 2017, 13, 2535–2548, doi:10.3762/bjoc.13.250

• ][1,2,4]triazine 4 (Figure 1A, Triazavirin®) was approved in Russia for the treatment of influenza [9]. This drug targets the viral protein haemagglutinin. The incorporation of an adamantyl moiety in azolo-azine structures could lead to the development of new multifunctional antiviral drugs. Previously

• ) was used to incorporate isotopic labels in the tetrazolo[1,5-b][1,2,4]triazine core (Scheme 1). The interaction of diazonium salt 8-15N2 derived from [2,3-15N2]-5-aminotetrazole 7-15N2 with ethyl α-formylphenylacetate (9) yielded compound 10-15N2. It was expected that the cyclization of 10-15N2 would

• give [1,2-15N2]-tetrazolo[5,1-c][1,2,4]triazine 11-15N2. Indeed, [2,3-15N2]-tetrazolo[1,5-b][1,2,4]triazin-7-one 13-15N2 was obtained (see below). Most likely, tetrazole 11-15N2 underwent a ring-opening process, yielding azide 12-15N2, and this process was followed by an alternative ring closure. This

Development of a method for the synthesis of 2,4,5-trisubstituted oxazoles composed of carboxylic acid, amino acid, and boronic acid

• Kohei Yamada,
• Naoto Kamimura and
• Munetaka Kunishima

Beilstein J. Org. Chem. 2017, 13, 1478–1485, doi:10.3762/bjoc.13.146

• 2,4,5-trisubstituted oxazoles in good yields. Keywords: one-pot oxazole synthesis; Suzuki–Miyaura coupling; triazine; 5-(triazinyloxy)oxazole; trisubstituted oxazole; Introduction Oxazoles are found in numerous natural products and are used as a broad range of artificial compounds [1][2]. In

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

• the reaction with the corresponding triazine chloride and N-methylmorpholine. These agents are then able to selectively react with the anomeric center of a fully unprotected saccharide in the presence of an amine base in a dehydrative manner analogous to DMC from the previous section. These triazine

• donors are then isolated and reacted in the following step. The power of these two-step strategies is the ability to obtain the much more challenging 1,2-cis glycoside. In their first study [90] DBT-MM was generated in situ and reacted with three saccharides to form the triazine donor in good yield and

A novel method for heterocyclic amide–thioamide transformations

• Walid Fathalla,
• Ibrahim A. I. Ali and
• Pavel Pazdera

Beilstein J. Org. Chem. 2017, 13, 174–181, doi:10.3762/bjoc.13.20

• extra proton to II to afford the quinazoline thione C2. On the other hand the free cyclohexylamine will add to cyclohexyl isothiocyanate (4) to form the thiourea 3. Similar results were obtained by Furumoto [40], and Sun [41] reported the application of cyanuric chloride (2,4,6-trichloro-1,3,5-triazine

Elongated and substituted triazine-based tricarboxylic acid linkers for MOFs

• Arne Klinkebiel,
• Ole Beyer,
• Barbara Malawko and
• Ulrich Lüning

Beilstein J. Org. Chem. 2016, 12, 2267–2273, doi:10.3762/bjoc.12.219

• Arne Klinkebiel Ole Beyer Barbara Malawko Ulrich Luning Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany 10.3762/bjoc.12.219 Abstract New triazine-based tricarboxylic acid linkers were prepared as elongated relatives of

• triazinetribenzoic acid (TATB). Additionally, functional groups (NO2, NH2, OMe, OH) were introduced for potential post-synthetic modification (PSM) of MOFs. Functionalized tris(4-bromoaryl)triazine “cores” (3a,3b) were obtained by unsymmetric trimerization mixing one equivalent of an acid chloride (OMe or NO2

• the methoxy group gave the respective amino and hydroxy-substituted triazine linkers. Keywords: isoreticular; linker; MOF; Suzuki coupling; triazine; Introduction A typical building block for many metal–organic frameworks (MOFs) [1][2][3][4] carries two functional groups such as carboxylic acids or

An effective one-pot access to polynuclear dispiroheterocyclic structures comprising pyrrolidinyloxindole and imidazothiazolotriazine moieties via a 1,3-dipolar cycloaddition strategy

• Alexei N. Izmest’ev,
• Galina A. Gazieva,
• Natalya V. Sigay,
• Sergei A. Serkov,
• Valentina A. Karnoukhova,
• Vadim V. Kachala,
• Alexander S. Shashkov,
• Igor E. Zanin,
• Angelina N. Kravchenko and
• Nina N. Makhova

Beilstein J. Org. Chem. 2016, 12, 2240–2249, doi:10.3762/bjoc.12.216

• regio- and diastereoselective one-pot method for the synthesis of new polynuclear dispiroheterocyclic systems with five stereogenic centers (dispiro[imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine-6,3′-pyrrolidine-2′,3′′-indoles]) comprising pyrrolidinyloxindole and imidazo[4,5-e]thiazolo[3,2-b]-1,2,4

• -triazine moieties has been developed. The method relies on a 1,3-dipolar cycloaddition of azomethine ylides generated in situ from isatin derivatives and sarcosine to 6-benzylideneimidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine-2,7-diones. Keywords: azomethine ylides; cycloaddition; diastereoselectivity

• of many natural and synthetic bioactive products [33][34][35][36][37][38][39][40]. The pyrimido[5,4-e]-1,2,4-triazine constitutes the core of the antibiotics fervenulin, xanthothricin, and reumycin [33][34]. Other hetero-annelated 1,2,4-triazines reveal antiviral effect against influenza A and B

Hydroxy-functionalized hyper-cross-linked ultra-microporous organic polymers for selective CO₂ capture at room temperature

• Partha Samanta,
• Priyanshu Chandra and
• Sujit K. Ghosh

Beilstein J. Org. Chem. 2016, 12, 1981–1986, doi:10.3762/bjoc.12.185

• types of microporous organic materials including covalent organic frameworks (COFs), conjugate microporous polymers (CMPs), porous polymeric networks (PPNs), porous aromatic frameworks (PAFs), covalent triazine framework (CTFs), etc. [19][20][21][22][23][24]. Hyper-cross-linked microporous organic

Potent triazine-based dehydrocondensing reagents substituted by an amido group

• Munetaka Kunishima,
• Daiki Kato,
• Nobu Kimura,
• Masanori Kitamura,
• Kohei Yamada and
• Kazuhito Hioki

Beilstein J. Org. Chem. 2016, 12, 1897–1903, doi:10.3762/bjoc.12.179

• University, 1-1-3 Minatojima Chuo-ku, Kobe 655-8586, Japan 10.3762/bjoc.12.179 Abstract This study describes the synthesis of triazine-based dehydrocondensing reagents substituted by amido substituents and demonstrates their efficiency for dehydrocondensing reactions in MeOH and THF. N-Phenylbenzamido

• feature enables the use of DMT-MM for dehydrocondensing reactions in water or alcohols to give amides without the recovery of hydrolyzed carboxylic acids and the formation of corresponding esters. DMT-MM is quantitatively synthesized from 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) and N-methylmorpholine

• intermediate in Scheme 1b, basically shows the same reactivity for aminolysis and alcoholysis regardless of which tertiary amine 5 was used (Scheme 1b,d). Therefore, it is reasonable to modify the activity of the 1,3,5-triazine ring that is involved in both steps shown in Scheme 1b by introducing another

New synthetic strategies for xanthene-dye-appended cyclodextrins

• Milo Malanga,
• Andras Darcsi,
• Mihaly Balint,
• Gabor Benkovics,
• Tamas Sohajda and
• Szabolcs Beni

Beilstein J. Org. Chem. 2016, 12, 537–548, doi:10.3762/bjoc.12.53

• formation of these byproducts could lead to depletion of the coupling agent by conversion to 2-hydroxy-4,6-dimethoxy-1,3,5-triazine (DMM-OH) and could explaining the moderate conversion of the starting material. It is worth emphasizing that the coupling of fluorescein based on DCC/HOBt in organic solvents

A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

• Steven C. Zimmerman

Beilstein J. Org. Chem. 2016, 12, 125–138, doi:10.3762/bjoc.12.14

• use of a melamine (2,4,6-triamino-1,3,5-triazine) unit for formation of a base-triplet, as shown in Figure 8b. Additional reports by Lehn [78] and McLaughlin [79] supported this approach and the melamine unit has more recently been used extensively by Bong [80]. So why did we once again become

• bonds, hypothetically forming base-triplet with 2,4,6-triamino-1,3,5-triazine. (c) Aromatic recognition unit tethered to intercalator in stacked and unstacked conformation. (d) Ligand 27, an inhibitor of MBNL1N sequestration. (a) CTG trinucleotide repeat expansion in DMPK gene produces expanded

The simple production of nonsymmetric quaterpyridines through Kröhnke pyridine synthesis

• Isabelle Sasaki,
• Jean-Claude Daran and
• Gérard Commenges

Beilstein J. Org. Chem. 2015, 11, 1781–1785, doi:10.3762/bjoc.11.193

• pathway [17][20], or a Suzuki–Miyaura cross-coupling reaction [21]. The use of triazine derivatives (which under particular conditions undergo an inverse Diels–Alder reaction) can also produce oligopyridines [22]. On the other hand, there are a limited number of reports dealing with the preparation of

• nonsymmetric quaterpyridines; Constable et al. proposed a multistep synthesis of 4’-(alkylthio)quaterpyridines [23] to avoid the Stille palladium-catalyzed coupling, whereas Fallahpour obtained the 4’-nitroquaterpyridine by employing the Stille coupling method [24]. Sauer et al. extended the use of triazine

Photo, thermal and chemical degradation of riboflavin

• Muhammad Ali Sheraz,
• Sadia Hafeez Kazi,
• Sofia Ahmed,
• Zubair Anwar and
• Iqbal Ahmad

Beilstein J. Org. Chem. 2014, 10, 1999–2012, doi:10.3762/bjoc.10.208

• ,N-dioctadecyl-[1,3,5]triazine-2,4,6-triamine [122], certain amino acids and indole [123][124], proteins [125] and metals such as Ag+, Ru2+ [126] to enhance the photostability of the vitamin. Quenchers: RF on the absorption of light is promoted to the excited singlet state and then to the excited