Polyaminoazide mixtures for the synthesis of pH-responsive calixarene nanosponges

• Antonella Di Vincenzo,
• Antonio Palumbo Piccionello,
• Alberto Spinella,
• Delia Chillura Martino,
• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2019, 15, 633–641, doi:10.3762/bjoc.15.59

• azide stretching of the reticulating agent, respectively. On the other hand, a tiny signal at 3140 cm−1 appears, which can be attributed to the Csp2–H stretching typical of the newly formed 1,2,3-triazole ring. The occurrence of the triazole ring is also accounted for by tiny signals at 1244, 1204, 1050

• NMR spectra (Figure 3) it is possible to recognize the peculiar cluster of four signals in the C-aromatic region, centered at ca. 127, 134, 146 and 154 ppm, due to the aromatic C atoms of the calixarene and triazole units. On the other hand, the aliphatic region shows a main signal centered at ca. 32

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• heterocycles, which were additionally extended by triazole moieties, the compounds with electron-donating groups showed intramolecular charge transfer character (ICT/TICT) of the excited states which was proved by solvatochromic dynamics and supported by DFT calculations. In the 7-deazapurine series this led

• towards 2-amino-6-triazolylpurine derivatives was performed in a more atom economic way. The latter synthesis does not require a double cycloaddition followed by replacement of one of the triazole moieties. The final structural proof for the compounds of the series 7a–f and 8a–f was obtained by spectral

• comparison between compound 8a and regioisomeric compound 5. The 1H NMR comparison showed two main differences in the spectra (Figure 3): 1) the H–C(triazole) signal of product 8a is shifted downfield from 8.69 to 9.10 ppm and 2) the appearance of a CH2 signal near the N atom is changed from multiplet at

Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• multiple click reactions of the diazido-telechelic PBD with a dialkynyl-containing azobenzene chromophore. The newly formed triazole moieties can tune and improve the photoresponsive properties of PBD. α,ω-Functional telechelic polymers also can be synthesized by acyclic diene metathesis (ADMET

Thermophilic phosphoribosyltransferases Thermus thermophilus HB27 in nucleotide synthesis

• Ilja V. Fateev,
• Ekaterina V. Sinitsina,
• Aiguzel U. Bikanasova,
• Maria A. Kostromina,
• Elena S. Tuzova,
• Larisa V. Esipova,
• Tatiana I. Muravyova,
• Alexei L. Kayushin,
• Irina D. Konstantinova and
• Roman S. Esipov

Beilstein J. Org. Chem. 2018, 14, 3098–3105, doi:10.3762/bjoc.14.289

• APRT limits the number of possible nucleotides that can be synthesized. Thus, for Thermus thermophilus HB27 APRT (TthAPRT), nucleotide synthesis is limited to the closest structural homologs of adenine (Table 1) [1]. Unfortunately, 1,2,4-triazole-3-carboxamide, its analogues, guanine, hypoxanthine, and

• phosphoribosyltransferase only [2]. Unfortunately, we did not find any product in reactions with compounds based on 1,2,4-triazole-3-carboxamide, which was also observed for E. сoli HPRT [15][16]. However, allopurinol and 8-azaguanine are substrates for TthHPRT, and 2-chloroadenine is a substrate for TthAPRT. For 2

Copper(I)-catalyzed tandem reaction: synthesis of 1,4-disubstituted 1,2,3-triazoles from alkyl diacyl peroxides, azidotrimethylsilane, and alkynes

• Muhammad Israr,
• Changqing Ye,
• Munira Taj Muhammad,
• Yajun Li and
• Hongli Bao

Beilstein J. Org. Chem. 2018, 14, 2916–2922, doi:10.3762/bjoc.14.270

• available lauroyl peroxide (2a), and TMSN3 (Table 1). In a preliminary experiment, the reaction of 1a with 2a in the presence of 10 mol % of CuCl in THF at 50 °C afforded 1,4-disubstituted 1,2,3-triazole 3a in 65% isolated yield (Table 1, entry 1). Surprisingly, under these conditions no CuAAC product

• , and 3ll). Remarkably, the chlorodiacyl peroxide also tolerated the reaction conditions to afford chloro-substituted triazole 3ee with good yield. Moreover, alkyl diacyl peroxides bearing a phenyl group, cyclopentyl group, or a cyclohexyl group also afforded good yields (3cc, 3mm, and 3nn

Photocatalyic Appel reaction enabled by copper-based complexes in continuous flow

• Clémentine Minozzi,
• Jean-Christophe Grenier-Petel,
• Shawn Parisien-Collette and
• Shawn K. Collins

Beilstein J. Org. Chem. 2018, 14, 2730–2736, doi:10.3762/bjoc.14.251

• complexes were poor catalysts, while when considering the diamine ligands the dq and bathophenthroline catalysts provided poor to modest yields. Also, BINAP and Xantphos-based catalysts tended to afford higher yields of 2, while amongst the diamines, the triazole-based complexes were almost all efficient at

Assembly of fully substituted triazolochromenes via a novel multicomponent reaction or mechanochemical synthesis

• Robby Vroemans,
• Yenthel Verhaegen,
• My Tran Thi Dieu and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 2689–2697, doi:10.3762/bjoc.14.246

• -triazole; Introduction Chromenes are important structural motifs and are omnipresent in nature and drugs for medicinal applications [1][2][3][4]. Vitamin E [5][6][7][8], arahypin-5 [9][10], THC and other cannabinoids [11][12][13][14] are only a few examples of biologically relevant chromenes. Hence, the

• , which enables them to undergo a high variety of reactions and functionalizations [15]. Combining the chromene core with the 1,2,3-triazole structural motif has led to some interesting new molecules [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. Very recently, spiro-fused

• ], via intramolecular cyclization of a diazomethane group and a nitrile [23], or via our recently reported NH-triazole synthesis starting from 6-methoxyflavanone [24]. Furthermore, 1,4,5-trisubstituted 1,2,3-triazole annulated chromenes have been reported via an intramolecular arylation reaction of 1,2,3

Nucleoside macrocycles formed by intramolecular click reaction: efficient cyclization of pyrimidine nucleosides decorated with 5'-azido residues and 5-octadiynyl side chains

• Jiang Liu,
• Peter Leonard,
• Sebastian L. Müller,
• Constantin Daniliuc and
• Frank Seela

Beilstein J. Org. Chem. 2018, 14, 2404–2410, doi:10.3762/bjoc.14.217

• macrocyclic systems [18][19][20][21][22][23][24][25]. DNA mimics with triazole linkages were constructed [26][27]. The click reaction was used to generate a cyclic ADP-ribose second messenger mimic [28]. Modelling studies using MM+ energy minimization showed that pyrimidine nucleosides are useful synthons for

• upfield shift (3–4 ppm) of the C4’-carbon signal was observed when the 5’-OH group was replaced by an azido group or a triazole moiety (Supporting Information File 1, Table S1). Irradiation of the triazole-H of 4 and 8, resulted in strong NOE’s at H-6, indicating that the Watson–Crick recognition sites of

• is observed (Supporting Information File 1, Figure S2). This might go back to stacking interactions of the nucleobase and the triazole residue. A similar relationship exists in the dC series with values of 4.2 for dC and 3.0 for 1 [35]. In contrast the pKa for cyclic dC 4 (3.2) did not further

Catalyst-free synthesis of 4-acyl-NH-1,2,3-triazoles by water-mediated cycloaddition reactions of enaminones and tosyl azide

• Lu Yang,
• Yuwei Wu,
• Yiming Yang,
• Chengping Wen and
• Jie-Ping Wan

Beilstein J. Org. Chem. 2018, 14, 2348–2353, doi:10.3762/bjoc.14.210

• , authentically mild conditions (40 °C stirring) as well as practical scalability. Keywords: additive-free; catalyst-free; cycloaddition; enaminones; on water; 1,2,3-triazole; Introduction Discovering sustainable chemical syntheses constitutes one central issue of modern organic chemistry. A large number of

• , including those reactions involving valuable C–C [7][8][9][10][11], C–heteroatom [12][13][14][15][16], heteroatom–heteroatom [17][18] bond formation as well as divergent cascade reactions [19][20][21][22][23], are presently taking place to guide the progress of sustainable organic synthesis. 1,2,3-Triazole

• development of these metal-catalyzed cycloaddition strategies [33][34][35]. Alongside the vast progress happened in MAAC-based 1,2,3-triazole synthesis, the past decade has witnessed the emergence of another powerful cycloaddition tool for the 1,2,3-triazole synthesis: the metal-free cycloaddition of azides

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• TTF is preferred as a station for the wheel over the triazole unit. However, after oxidation, the more hydrophilic dication TTF2+ is less favored and the ring moves to the triazole. Both switching states were fully characterized by UV–vis, 1H,1H-NOESY NMR spectroscopy, and cyclic voltammetry. The

Revisiting ring-degenerate rearrangements of 1-substituted-4-imino-1,2,3-triazoles

• James T. Fletcher,
• Matthew D. Hanson,
• Joseph A. Christensen and
• Eric M. Villa

Beilstein J. Org. Chem. 2018, 14, 2098–2105, doi:10.3762/bjoc.14.184

• James T. Fletcher Matthew D. Hanson Joseph A. Christensen Eric M. Villa Department of Chemistry, Creighton University, 2500 California Plaza, Omaha, NE 68178, U.S.A. 10.3762/bjoc.14.184 Abstract The 1-substituted-4-imino-1,2,3-triazole motif is an established component of coordination compounds

• four imine products via a dynamic equilibrium of condensation, rearrangement and hydrolysis steps. Kinetic studies utilizing 1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carbaldehyde with varying amines showed rearrangement rates sensitive to both steric and electronic factors. Such measurements were

• facilitated by a high throughput colorimetric assay to directly monitor the generation of a 4-nitroaniline byproduct. Keywords: colorimetric assay; condensation; imine exchange; rearrangement; 1,2,3-triazole; Introduction Examples of multidentate chelators comprised of 1,2,3-triazole units have surged in

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• concentrations and gel-to-sol transition temperatures were also determined for each case. In addition, the superior squaramide diester gelator was compared with an analogue triazole-based gelator in terms of critical gelation concentration, gelation kinetics and thermal phase transition. Keywords: glutamic acid

• properties of supramolecular gels [33]. Specifically, we exchanged the amide group of N-stearoyl-L-glutamic acid (1, Figure 1), a known LMW gelator [34], by its non-classical isostere [35][36] 1,4-disubstituted 1,2,3-triazole 2 (Figure 1). This approach enabled us to fine-tuning the gelation capacity and the

• due to the delicate equilibrium between metastable gel and thermodynamically stable crystalline phases [39][40]. Squaramide 3 formed stable gels in the same number of solvents than the analogue triazole-based gelator 2, which was previously found to be superior to the amide 1 [33]. Similarly to 3, CGC

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• carbamates, urea and non-basic heterocycles (Scheme 11) [54]. The scope covers a multitude of electron-poor and electron-rich arenes which can be reacted with carbamates, urea, pyrazole and triazole derivatives to furnish aminated products. The authors address the various reactivities observed with respect

• group report are scaffolds and moieties seen in typical medicinal chemistry syntheses. There are numerous examples of amino acid-derived substrates, either as the methoxybenzene electrophile (tyrosine type derivatives) or as the nucleophile (histidine and related structures such as the depicted triazole

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• was elaborated for the naked-eye detection of ADP with a detection limit of 0.5 mM. Keywords: ADP; amphiphile; ATP; calix[4]arene; CuAAC; eosin Y probe; molecular recognition; polydiacetylene; self-assembly; triazole; Introduction During the last two decades many researcher groups have paid much

• target BOC-protected products 9a,b and 11a,b were isolated in good yields. The appearance of a new signal of triazole ring protons and a new set of signals of the methylene group protons between the triazole ring and the tertiary nitrogen atom as well as the signals of the ethylene fragments and BOC

An amphiphilic pseudo[1]catenane: neutral guest-induced clouding point change

• Tomoki Ogoshi,
• Tomohiro Akutsu and
• Tada-aki Yamagishi

Beilstein J. Org. Chem. 2018, 14, 1937–1943, doi:10.3762/bjoc.14.167

• , triazole), 7.15 (s, 2H, phenyl), 6.93 (s, 2H, phenyl), 6.89 (s, 2H, phenyl), 6.80 (s, 2H, phenyl), 6.62 (s, 2H, phenyl), 5.21 (dd, 4H, methylene), 3.50–4.14 (m, 110H, methylene), 3.34–3.36 (m, 24H, methyl), −0.27–0.72 (br, 20H, methylene of alkyl chain) ppm; 13C NMR (125 MHz, CDCl3) δ 150.4, 149.8, 149.7

Efficient catenane synthesis by cucurbit[6]uril-mediated azide–alkyne cycloaddition

• Antony Wing Hung Ng,
• Chi-Chung Yee,
• Kai Wang and
• Ho Yu Au-Yeung

Beilstein J. Org. Chem. 2018, 14, 1846–1853, doi:10.3762/bjoc.14.158

• proximity and their cycloaddition will be facilitated. As the cycloaddition is preceded by CB[6] binding, triazole formation will therefore ensure the interlocking of the CB[6]. A [1 + 1] macrocyclization of the diazide and dialkyne will then result in the exclusive formation of the [3]catenane with no

• interactions are preserved under the MS conditions. Inclusion of the triazole in the CB[6] cavity was evidenced by the upfield shifted triazole resonance from 8.5 ppm to 6.4 ppm when compared with that of free triazole in non-interlocked system [22][24][25]. NOE cross peaks between the triazole and CB[6

• upfield shifted triazole 1H NMR resonances of Cat-2–Cat-10 at ca. 6.4 ppm are consistent with the inclusion of the triazole in the CB[6] cavity [22][24][25]. The ESIMS, HRMS and MS2 spectra are all consistent with the [3]catenanes with a similar fragmentation behavior as that of Cat-1. The 1H NMR, 13C NMR

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3⁺ + 2]-cycloaddition/rearrangement reactions

• Lin-bo Luan,
• Zi-jie Song,
• Zhi-ming Li and
• Quan-rui Wang

Beilstein J. Org. Chem. 2018, 14, 1826–1833, doi:10.3762/bjoc.14.155

• furnishing the tricyclic 1,2,4-triazole-fused 1,4-benzodiazepines. Keywords: 1,4-benzodiazepine (BDZ); cyclization; hydrazones; oxidation; rearrangement; Introduction Heterocyclic compounds comprising a 1,4-benzodiazepine (BDZ) ring have been a topic of continued interest as they exhibit a wide spectrum of

• achieved when a third heterocycle, especially a 1,2,4-triazolo moiety, was attached to the seven-membered ring as part of 1,4-benzodiazepine [13][14]. Among various reported 1,2,4-triazole-annulated 1,4-benzodiazepines, triazolam (I), estazolam (II), alprazolam (III) and pyrazolam (IV) are prominent

• . Conclusion In summary, an appealing series of 1,2,4-triazole-fused 1,4-benzodiazepines 10 and 13 were prepared via the [3+ + 2]-cycloaddition reaction followed by a cationic [1,2]-rearrangement reaction. The procedure is general and has several advantages such as ready availability of starting materials

Synthesis and photophysical studies of a multivalent photoreactive Ru^II-calix[4]arene complex bearing RGD-containing cyclopentapeptides

• Sofia Kajouj,
• Lionel Marcelis,
• Alice Mattiuzzi,
• Adrien Grassin,
• Damien Dufour,
• Pierre Van Antwerpen,
• Didier Boturyn,
• Eric Defrancq,
• Mathieu Surin,
• Julien De Winter,
• Pascal Gerbaux,
• Ivan Jabin and
• Cécile Moucheron

Beilstein J. Org. Chem. 2018, 14, 1758–1768, doi:10.3762/bjoc.14.150

• (CuAAC). Note that the triazole moieties that would result from such a cycloaddition are known to be stable towards hydrolysis and protease, which allows their use in a biological environment [72]. For the CuAAC, the use of CuI-generated in situ from a mixture of CuSO4·5H2O and sodium ascorbate is often

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• mechanism that first involves the formation of a 2’-iodobiphenyl-2-azide promoted by the copper complex. The latter then catalyzes an intermolecular [3 + 2] cycloaddition with the alkyne. Finally, the copper-triazole moiety inserts intramolecularly into the second Ar–I bond, allowing a ring closure after

Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

• Alberto Spinella,
• Marco Russo,
• Antonella Di Vincenzo,
• Delia Chillura Martino and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

• was assessed by means of FTIR and 13C{1H} CP-MAS solid-state NMR techniques, whereas morphological characterization was provided by SEM microghaphy. The materials were proved to possess pH-dependent sequestration abilities, due to the presence of the weakly basic triazole linkers. Sequestration

• ]) between a heptakis(6-azido-6-deoxy)-β-cyclodextrin and a tetrakis(propargyloxy)calix[4]arene [11][31][32]. In this way, a random disposition of the co-monomer units linked by 1,2,3-triazole units is achieved. The obtained CyCaNSs benefit from several advantages. First, the properties of the material can

• polymeric structure and can be subsequently subjected to further chemical transformation, opening the way to a possible post-functionalization [31]. This, in turn, largely improves the possible tunability in the properties of the materials obtained. Finally, the triazole linker present in the structure is

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

• Cristina Cebrián and
• Matteo Mauro

Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• same N3 coordinating both Cu atoms attacks the terminal carbon of the polarized double bond with concerted cleavage of one of the two copper atoms. The copper triazolide formed in this way is then hydrolyzed to the final triazole. The same presumption (Scheme 17) concerning the role of the two Cu atoms

• -phenylbut-1-yne [119] tridentate tris(benzimidazole) ligands completely failed and tris(triazole) ligands gave only poor to moderate yields (16–65%) even at 100 °C, whereas all the bidentate ligands (phenanthrolines L1, L2 and diimidazo[1,2-a:2',1'-c]quinoxalines L3–L6) were found to be more efficient both

Oligonucleotide analogues with cationic backbone linkages

• Melissa Meng and
• Christian Ducho

Beilstein J. Org. Chem. 2018, 14, 1293–1308, doi:10.3762/bjoc.14.111

• motifs. Such artificial neutral linkages include, among others, sulfone [14], amide [15][16][17][18][19][20][21][22], triazole [23][24][25][26][27], phosphoramidate [28] and phosphate triester [29] moieties. Using a different approach, positive charges have been introduced into nucleic acid structures

Novel unit B cryptophycin analogues as payloads for targeted therapy

• Eduard Figueras,
• Adina Borbély,
• Mohamed Ismail,
• Marcel Frese and
• Norbert Sewald

Beilstein J. Org. Chem. 2018, 14, 1281–1286, doi:10.3762/bjoc.14.109

• conjugation of the novel cryptophycin analogues across an appropriate linker to an antibody or peptide. Either a virtually uncleavable triazole (introduced by CuAAC) or scissile ester, carbonate, or carbamate moieties were taken into account. The synthesis of the modified unit B (Scheme 1) started with the

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93