Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• between various azoles and internal alkynes is mediated by benziodoxole triflate as the electrophile in a trans-fashion, affording azole-bearing vinylbenziodoxoles in moderate to good yields. The tolerable azole nuclei include pyrazole, indazole, 1,2,3-triazole, benzotriazole, and tetrazole. The iodanyl

• reaction of azoles with alkynes and iodine(III) electrophile, benziodoxole triflate (BXT, 1; Scheme 1c). Displaying exclusive trans-selectivity, the reaction tolerates a broad range of azoles, including pyrazole, 1,2,3-triazole, tetrazole, indazole, and benzotriazole, with internal alkynes as coupling

• yield in a ratio of 7:3. Indazole and its 4-bromo and 6-methoxycarbonyl analogues afforded the expected N1-alkenylated products 4ea–4ga in 43–68% yields. 1,2,3-Triazole and benzotriazole both smoothly participated in the reaction to give their respective products 4ha and 4ia in 60% and 81% yields

Catalytic multi-step domino and one-pot reactions

• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2024, 20, 254–256, doi:10.3762/bjoc.20.25

• trisubstituted 3-iodoindoles, which are valuable substrates for the synthesis of, e.g., blue emitters in good yield [16]. The power of double click reactions toward functionalized bis(1,2,3-triazole) derivatives has been demonstrated in the Full Research Paper by Reissig and Yu. The authors successfully combined

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• good yield (this represented a formal synthesis to clozapine [26], if the procedure of Rao [27] is used, which entails heating 4e with 1-methylpiperidine and Ti(IV)Cl4, Scheme 4). Also compound 4a can be transformed to Hügel's 1,2,3-triazole-DBDAP using the methodology described in their report (Scheme

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• 1,2,3-triazole ring, either an additional pyrimidinedione, 4-nitroimidazole, isoxazole, 1,3,4-triazole, 2-oxochromone or thiazole ring, has been developed. The process was facilitated by a strong base and includes the cycloaddition reaction of 3,3-diaminoacrylonitriles (2-cyanoacetamidines) to

• -triazole-4-carbimidamides with alkyl, allyl, propargyl, benzyl, cycloalkyl, and indolyl substituents at the N1 position . Keywords: Cornforth rearrangement; cycloaddition reactions; 3,3-diaminoacrylonitriles; heterocyclic azides; 1,2,3-triazole; Introduction Heteroaryl amidines are widely used in the

• synthesis of various nitrogen-containing heterocyclic compounds and have a variety of biological activities [1][2][3][4]. After the discovery of click chemistry [5][6] involving the CuAAC method of 1,2,3-triazole synthesis [7][8], there has been great interest of studing the chemical and biological

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• ][19]. These mesoionic carbenes (MICs), together with their pyrazolin-4-ylidene [20] and 1,2-isoxazol-4-ylidene cousins [21], are the strongest donors among the various types of carbene ligands known thus far [22]. A distinct class of mesoionic or abnormal carbenes based on the 1,2,3-triazole ring

• -disubstituted-1,2,3-triazole derivatives is readily achieved via the copper(I)-catalyzed [3 + 2] cycloaddition of an azide and a terminal alkyne (CuAAC) [63][64][65]. A further alkylation of the N3 position with an alkyl halide is an equally straightforward procedure that ultimately affords a large assortment

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• pyrazole derivatives (including indazole), benzimidazole, 1,2,3-triazole, indole, carbazole, indoline, quinazoline, and isoquinoline. Nevertheless, many heterocyclic motifs still remain beyond the attention of researchers. For example, glutarimides that incorporate tetrazole and 1,2,4-triazole substituents

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• complex obtainable via a straightforward synthesis, with improved solubility, concerning our previous Co(II) complexes [21]. Thus, the new Co(II) complex bears two 1-benzyl-4-(quinolin-2-yl)-1H-1,2,3-triazole (BzQuTr) units, that were obtained through a copper-catalyzed alkyne–azide cycloaddition (CuAAC

• maintaining high selectivity for carbon products. Results and Discussion Synthesis and characterization of the new Co(II)-based catalyst The novel cobalt(II) complex 1 was synthesized in dry methanol (MeOH) by mixing in a 2:1 ratio, the chelating diimine ligand, 1-benzyl-4-(quinolin-2-yl)-1H-1,2,3-triazole

• coordinating nitrogen of the 1,2,3-triazole units. The nitrogen atoms of the two quinoline moieties are therefore trans to each other. This conformation might be induced by the cobalt precursor Co(NCS)2(py)4, which has already the NCS monodentate ligands cis to each other, as it was not the case for other Co

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• ][12], inflammation [13], bacterial [14][15], and viral infections [16]. Hence, new ways to rapidly and efficiently access 1,2,3-triazole heterocyclic motifs are still in demand. However, methods for the direct synthesis of 1,4,5-trisubstituted-1,2,3-triazoles are limited [17]. This is highly desirable

• since the selective introduction of substituents at three different positions on the 1,2,3-triazole ring can augment the features of the molecule. Triazoles are also found in many biologically important molecules and functionalized materials [11][12][13][14][15][16]. 1,4,5-Trisubstituted-1,2,3-triazoles

• -difluoroalkenes that subsequently undergoes a cycloaddition reaction. Results and Discussion While investigating 1,3-dipolar cycloaddition reactions between organic azides and gem-difluoroalkenes to obtain the 4-fluoro-1,4-disubstituted 1,2,3-triazole regioisomers, we observed an interesting reactivity while

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• copper(I) bromide in CH2Cl2 (Scheme 24) [31]. Nakamura et al. synthesized for the first time a copper complex with a 1,2,3-triazole carbene ligand in 2011. Complexes of copper with 1,4-diphenyl-, 1,4-dimesityl-, and 1-(2,6-diisopropylphenyl)-4-(3,5-xylyl)-1,2,3-triazol-5-ylidene were prepared through

• bulky azide 134 to afford 1-(2,6-dimesityl)phenyl-4-(2-pyridyl)-1,2,3-triazole (135), which is otherwise difficult to achieve (Scheme 51). Oro and co-workers employed complexes 78a and 78a-MCH-41 (Scheme 27) as homogeneous and heterogeneous catalysts, respectively, for the [3 + 2] cycloaddition of

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• (bromomethyl)benzene furnished geometrically differing bis(1,2,3-triazole) derivatives. The use of tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA) as ligand for the click step turned out to be very advantageous. The compounds with 1,2-oxazinyl end groups can potentially serve as precursors of divalent

• -catalyzed version can generally be executed at room temperature and it affords exclusively 1,4-disubstituted 1,2,3-triazole derivatives, thus allowing a controlled and highly efficient connection of a variety of molecular building blocks. This “Lego-approach” found countless applications and the bestowal of

• converted into several multivalent compounds B by amine or amide bond formations [44][45][46][47]. The transformation of the corresponding azidopyrans and azidooxepanes C or E into multivalent 1,2,3-triazole derivatives D and F by Meldal–Sharpless cycloadditions with suitable alkynes proceeded generally in

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• -methyltribenzotriquinacene-2,3,6,7,10,11-hexayl)hexakis(oxy))hexaacetate (TBTQ-C6) and 2,2',2'',2''',2'''',2'''''-((((12d-methyltribenzotriquinacene-2,3,6,7,10,11-hexayl)hexakis(oxy))hexakis(methylene))hexakis(1H-1,2,3-triazole-4,1-diyl))hexaacetate (TBTQ-CB6), which act as host molecules to bind to guest molecules to

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• connect two diverse moieties in a single framework. Therefore, this review focuses on the synthesis and photophysical studies of β- and meso-substituted and 1,2,3-triazole-fused porphyrin conjugates. All of the porphyrin conjugates discussed here are synthesized via a copper(I)-catalyzed Huisgen 1,3

• -dipolar cycloaddition reaction between an azide and a terminal alkyne, also popular as "click reaction" or CuAAC reaction. Moreover, the 1,2,3-triazole ring also serves as a spacer and an electron transfer bridge between the porphyrin and the attached chromophores. In order to provide a critical overview

• of the synthesis and properties of various porphyrin-triazole hybrids, this review will discuss some of the key reactions involved in the preparation of triazole-linked porphyrin conjugates. Keywords: azide–alkyne; click chemistry; CuAAC; 1,3-dipolar cycloaddition; porphyrin; 1,2,3-triazole

A novel bis-triazole scaffold accessed via two tandem [3 + 2] cycloaddition events including an uncatalyzed, room temperature azide–alkyne click reaction

• Ksenia Malkova,
• Andrey Bubyrev,
• Vasilisa Krivovicheva,
• Dmitry Dar’in,
• Alexander Bunev and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1636–1641, doi:10.3762/bjoc.18.175

• ; Introduction 1,2,3-Triazoles are well-established heterocycles in drug discovery [1] and are even considered pharmacophores (i.e., structural motifs defining the compound’s biological activity profile) on their own [2]. Therefore, synthetic methods allowing to construct a 1,2,3-triazole heterocycle are a

• molecular scaffold. Pondering various opportunities for post-condensational modifications of the 1,5-disubstituted 1,2,3-triazole core according to this strategy, we turned our attention to such powerful transformation as the azide–alkyne [3 + 2] cycloaddition (also known as the azide–alkyne click reaction

• ) [6]. Indeed, if an alkyne and an azido group were strategically positioned within the structure of the amine and the aldehyde components for the reaction with 1, subsequent intramolecular azide–alkyne cycloaddition would be a feasible event which would create a polycyclic bis-1,2,3-triazole framework

New triazole-substituted triterpene derivatives exhibiting anti-RSV activity: synthesis, biological evaluation, and molecular modeling

• Elenilson F. da Silva,
• Krist Helen Antunes Fernandes,
• Denise Diedrich,
• Jessica Gotardi,
• Marcia Silvana Freire Franco,
• Carlos Henrique Tomich de Paula da Silva,
• Ana Paula Duarte de Souza and
• Simone Cristina Baggio Gnoatto

Beilstein J. Org. Chem. 2022, 18, 1524–1531, doi:10.3762/bjoc.18.161

• drug for its treatment, however, its clinical use has been limited due to its side effects. Here, we designed two new nitroaryl-1,2,3-triazole triterpene derivatives as novel anti-RSV drugs. Their anti-RSV and cytotoxic activity were evaluated in vitro, RSV protein F gene effects by RT-PCR and

• triterpenes to synthesize 1,2,3-triazole derivatives via the Huisgen 1,3-cycloaddition reaction, but, as far as we know, this is the first report of the application of click chemistry to triterpenes with this objective [35][36][37]. Click chemistry is one of the most important tools used for the synthesis of

• = 44.4 and 14.29 µM, respectively). Although betulinic acid (1) exhibited greater antiviral activity than ursolic acid (2), the introduction of a nitroaryl-1,2,3-triazole substituent in 2 was more efficient than its introduction in scaffold 1. Moreover, all tested compounds showed low cytotoxicity in

Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof

• Laura Holzhauer,
• Chloé Liagre,
• Olaf Fuhr,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111

• diversity of metal complexes incorporating 1,2,3-triazoles as ligands have been reported [16][17][18]. Triazole ligands with N-heterocycles such as Pyta (4-(2-pyridyl)-1,2,3-triazole) and related structures were employed to obtain novel metal complexes as catalysts [19][20] and imaging probes [21], as well

• , a small library of 1,2,3-triazole-substituted quinoxalines was synthesized applying the method of Chattopadhyay et al. [10] with minor adjustments. Altogether, a series of 21 different aliphatic and aromatic terminal alkynes were reacted with tetrazolo[1,5-a]quinoxaline and Cu(I) triflate as a

• conditions, see Supporting Information File 1 for details. Synthesis of 1,2,3-triazole-substituted quinoxalines via CuAAC from tetrazolo[1,5-a]quinoxaline (11a). aSynthesis of 14j* from 14j = Et2NH, K2CO3, DMF, 70 °C, 1 d. Mechanism of CuAAC vs denitrogenative annulation. Synthesis of bis(tetrazolo)[1,5-a:5

Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes

• Mio Matsumura,
• Kaho Tsukada,
• Kiwa Sugimoto,
• Yuki Murata and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 863–871, doi:10.3762/bjoc.18.87

• -triazoles [33]. Based on these findings, we examined the reaction of Cu-mediated AAC. The reaction of 4aa with benzyl azide in the presence of one equivalent of CuI and pentamethyldiethylenetriamine (PMDETA) in THF at 60 °C gave the desired 5-selanyl-1,2,3-triazole 8 in 72% yield. This reaction yielded a

• regioselective 1,3-dipolar azide–alkyne cycloaddition to form 5-selanyl-1,2,3-triazole. The investigation of the biological activity of the compounds obtained in this study and the application of this synthesis route using other heterocycles, instead of imidazopyridine, are currently underway in our laboratory

Anomeric 1,2,3-triazole-linked sialic acid derivatives show selective inhibition towards a bacterial neuraminidase over a trypanosome trans-sialidase

• Peterson de Andrade,
• Sanaz Ahmadipour and
• Robert A. Field

Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24

• natural substrate for sialidases and its chemical modification has been a useful approach to generate potent and selective inhibitors. Aiming at advancing the discovery of selective Trypanosoma cruzi trans-sialidase (TcTS) inhibitors, we have synthesised a small series of anomeric 1,2,3-triazole-linked

• differences in sialidases that need to be addressed in order to achieve selective inhibition. Keywords: inhibition; neuraminidase; sialic acid; trans-sialidase; 1,2,3-triazole; Introduction Amongst the diversity of glycans present in living organisms, N-acetylneuraminic acid (Neu5Ac, sialic acid) is

• series of C-2-modified sialic acid bearing a monosaccharide tethered via 1,2,3-triazole ring (sialylmimetic neoglycoconjugates) [19] that showed 67–91% inhibitory activity at 1 mM. We now envisaged replacing the monosaccharide moiety by (hetero)aromatic substituents (Figure 2A) expecting better

Synthesis and antimicrobial activity of 1H-1,2,3-triazole and carboxylate analogues of metronidazole

• Satya Kumar Avula,
• Syed Raza Shah,
• Khdija Al-Hosni,
• Muhammad U. Anwar,
• Rene Csuk,
• Biswanath Das and
• Ahmed Al-Harrasi

Beilstein J. Org. Chem. 2021, 17, 2377–2384, doi:10.3762/bjoc.17.154

• -Wittenberg, Kurt-Mothes-Str. 2, d-06120, Halle (Saale), Germany 10.3762/bjoc.17.154 Abstract Herein, a series of novel 1H-1,2,3-triazole and carboxylate derivatives of metronidazole (5a–i and 7a–e) were synthesized and evaluated for their antimicrobial activity in vitro. All the newly synthesized compounds

• inhibiting effects compared to the activity of the parent compound. Amongst the tested compounds 5b, 5c, 5e, 7b and 7e displayed excellent potent antimicrobial activity. The current study has demonstrated the usefulness of the 1H-1,2,3-triazole moiety in the metronidazole skeleton. Keywords: antimicrobial

• agents; carboxylate analogues; 1H-1,2,3-triazole analogues; metronidazole; synthesis; Introduction Metronidazole (1) is an important antimicrobial agent which has been clinically used successfully for a long time. It was originally used for the treatment of infections caused by Trichomonas varginalis

(Phenylamino)pyrimidine-1,2,3-triazole derivatives as analogs of imatinib: searching for novel compounds against chronic myeloid leukemia

• Luiz Claudio Ferreira Pimentel,
• Lucas Villas Boas Hoelz,
• Henayle Fernandes Canzian,
• Frederico Silva Castelo Branco,
• Andressa Paula de Oliveira,
• Vinicius Rangel Campos,
• Floriano Paes Silva Júnior,
• Rafael Ferreira Dantas,
• Jackson Antônio Lamounier Camargos Resende,
• Anna Claudia Cunha,
• Nubia Boechat and
• Mônica Macedo Bastos

Beilstein J. Org. Chem. 2021, 17, 2260–2269, doi:10.3762/bjoc.17.144

• )pyrimidine-pyridine (PAPP) group as a pharmacophoric fragment, and these compounds were biologically evaluated. The synthesis of twelve new compounds was performed in three steps and assisted by microwave irradiation in a 1,3-dipolar cycloaddition to obtain 1,2,3-triazole derivatives substituted on carbon C

• in the docking studies. Keywords: chronic myeloid leukemia; 1,3-dipolar cycloaddition; imatinib; (phenylamino)pyrimidine-pyridine; 1,2,3-triazole; Introduction Changes in tyrosine kinase proteins (TKPs), either by mutation or chromosomal translocation, can turn them into potent oncogenes

• analogs [12][13], in this work, we designed a series of imatinib 1,2,3-triazole analogs 1a,b and 2a–j (Figure 1). The 1,2,3-triazoles are heterocyclic compounds, consisting of a five-membered ring, containing two carbon atoms and three nitrogen atoms [14]. The application of click chemistry, a concept

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• synthesis of a wide variety of relevant 1,4,5-trisubstituted 1,2,3-triazole molecules are reported. The synthesis of this category of diverse fully functionalized 1,2,3-triazoles has become a necessary and unique research subject in modern synthetic organic key transformations in academia, pharmacy, and

• -triazoles; N-containing heterocycles; 1,4,5-trisubstituted 1,2,3-triazoles; Introduction A high number of N-heterocycles [1][2][3][4] are identified, and this number is increasing very quickly [5][6][7][8]. Among them, the small heterocyclic ring of the 1,2,3-triazole is present in a broad variety of

• compounds with not only biological but also industrial significance [9][10][11]. It possesses a cyclic scaffold with carbon and three nitrogen elements in the ring [12][13][14][15]. An immense versatility of biological properties is possessed by 1,2,3‐triazole heterocyclic systems, and many strategies are

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

• . The heterocyclic structures which were found to be attached to these double-headed nucleosides include triazolophthalazine [11], 4,6-di-tert-butylbenzoxazole [12], mesitylisoxazole [13], 5-trimethylsilyl-1,2,3-triazole [14], 1-pivaloyloxymethyl-1H-1,2,3-triazole [15], 1,3,4-oxadiazino[6,5-b]indole [16

• ]. Nielsen and co-workers [43] synthesized 2′-(4-(thymin-1-ylmethyl)-1,2,3-triazole-1-yl)- and 2′-(4-(N6-benzoyladenine-9-ylmethyl)-1,2,3-triazole-1-yl)-substituted double-headed nucleosides of 2′-deoxy-5′-O-(4,4′-dimethoxytrityl)uridine (14 and 15) from the nucleoside azide 12 which in turn was obtained by

• complementary bases [34]. Nielsen and co-workers [23] synthesized the double-headed nucleoside 1-(5′-O-(4,4′-dimethoxytrityl)-2′-C-((4-(pyren-1-yl)-1,2,3-triazole-1-yl)methyl)arabinofuranosyl)uracil (41) starting from spironucleoside 2 which in turn was synthesized from uridine following a procedure reported in

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

Synthesis of β-triazolylenones via metal-free desulfonylative alkylation of N-tosyl-1,2,3-triazoles

• Soumyaranjan Pati,
• Renata G. Almeida,
• Eufrânio N. da Silva Júnior and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2021, 17, 762–770, doi:10.3762/bjoc.17.66

• 61% yields, respectively. The reaction of mild electron withdrawing 3-methoxyphenyl-1,2,3-triazole 1e led to product 3h in low yield (38%) whereas the corresponding 4-tert-butylphenyl-1,2,3-triazole 1f afforded the product 3i in 53% yield. Later, the reaction was performed using various

• the scope of cyclohexane-1,3-dione 2a is limited. On the contrary, dimedone (2d) did not react with N-tosyl-1,2,3-triazole, but reacted with N-mesyl-1,2,3-triazole to form the 5,5-dimethyl-3-oxo-cyclohex-1-en-1-yl methanesulfonate intermediate 4a. The highly substrate-dependent nature of the reaction

• excellent yields. Nucleophilic addition to 5- and 6-membered cyclic tosyloxyenones. Synthesis, functionalization and applications of triazoles. The reaction was performed using 0.2 mmol N-tosyl-1,2,3-triazole 1 and 0.2 mmol of cyclohexyl-1,3-dione 2. Yields are determined after silica gel column

Effective microwave-assisted approach to 1,2,3-triazolobenzodiazepinones via tandem Ugi reaction/catalyst-free intramolecular azide–alkyne cycloaddition

• Maryna O. Mazur,
• Oleksii S. Zhelavskyi,
• Eugene M. Zviagin,
• Svitlana V. Shishkina,
• Vladimir I. Musatov,
• Maksim A. Kolosov,
• Elena H. Shvets,
• Anna Yu. Andryushchenko and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2021, 17, 678–687, doi:10.3762/bjoc.17.57

• into two well-resolved doublets and two triplets slightly shifted downfield. This phenomenon can be explained by the loss of conformational motion of the aromatic ring and the formation of the hard molecular carcass of the 7-membered ring fused with a 1,2,3-triazole cycle. Then we applied higher

Deoxygenative C2-heteroarylation of quinoline N-oxides: facile access to α-triazolylquinolines

• Geetanjali S. Sontakke,
• Rahul K. Shukla and
• Chandra M. R. Volla

Beilstein J. Org. Chem. 2021, 17, 485–493, doi:10.3762/bjoc.17.42

• reaction conditions (Scheme 1b) [58][59][60][61][62]. Results and Discussion We initiated our trials employing easily accessible quinoline N-oxide (1a) and 1-tosyl-4-phenyl-1,2,3-triazole (2a) as model substrates. Subjecting the reaction mixture to 100 °C in the presence of DIPEA in 1,2-dichloroetane (DCE

• ) with 4-phenyl-1-tosyl-1H-1,2,3-triazole (2a, 8.3 mmol, 1.2 equiv) at room temperature for 1 h, the reaction worked equally well and produced the desired product 3a in 87% yield (1.6 g). In addition, to enlarge the simplicity of the developed protocol for selective C2-triazolylation of quinoline

• the stepwise pathway. The plausible mechanism for the C2-triazolylation of quinoline N-oxides is presented in Scheme 7 [64]. The reaction initiates by the nucleophilic attack of quinoline N-oxide, e.g., 1a, on the sulfonyl group of N-sulfonyl-1,2,3-triazole 2, leading to the formation of intermediate