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

• hybrids. The selective N-functionalization of the triazene-protected pyrazoles was conducted, and the cleavage of triazenylpyrazoles to the corresponding azides was described for the first time with regioisomer 17, whereas regioisomer 18 is acid-insensitive and cannot be converted. The azides were reacted

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• also simplifies product isolation and purification and improves the overall sustainability of the process [23][24]. However; specific reaction requirements ensure efficient and selective utilization of solvents. Marvi and Talakoubi carried out the Cannizzaro reaction [25] using montmorillonite K-10 and

• ability to introduce carboxylic acid functionalities and facilitate functional group interconversions makes it a valuable method for chemists engaged in the design and synthesis of diverse organic compounds. A selection of applications is depicted herein. Mehta et al. established a highly selective

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

• a methoxy group were transformed into the products in good yields (3la–na). 4-(Trifluoromethoxy)iodobenzene also well participated in this reaction, affording 3oa in 65% yield. Aryl iodides having fluoro and chloro substituents underwent selective C–I bond cleavage to provide monoalkylated products

Computation-guided scaffold exploration of 2E,6E-1,10-trans/cis-eunicellanes

• Zining Li,
• Sana Jindani,
• Volga Kojasoy,
• Teresa Ortega,
• Erin M. Marshall,
• Khalil A. Abboud,
• Sandra Loesgen,
• Dean J. Tantillo and
• Jeffrey D. Rudolf

Beilstein J. Org. Chem. 2024, 20, 1320–1326, doi:10.3762/bjoc.20.115

• -induced cyclization of the eunicellane skeleton (Figure 2). When 1 and 2 were individually subjected to acidic conditions (i.e., TFA in CHCl3), both cyclized into 6/6/6-tricyclic skeletons via a selective C2–C7 cyclization after protonation at C6 to give trans-BC ring systems (i.e., cis,trans-6/6/6 for 1

• . Scaffold exploration of the eunicellane skeleton During protonation-induced cyclization of 1 and 2, the C6–C7 alkene showed higher nucleophilicity than either of the other two double bonds likely due to the unique conformation of the eunicellane skeleton. This selective reactivity was further supported

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

Oxidative hydrolysis of aliphatic bromoalkenes: scope study and reactivity insights

• Amol P. Jadhav and
• Claude Y. Legault

Beilstein J. Org. Chem. 2024, 20, 1286–1291, doi:10.3762/bjoc.20.111

• for the synthesis of dialkyl bromoketones would result in a mixture of regioisomers given the presence of enolizable protons on each side of the ketone (Scheme 1b). Recently Toy et al. have disclosed the selective synthesis of unsymmetrical α-haloketones by reductive halogenation of an α,β-unsaturated

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• , controlling the regioselectivities of multiple functionalizations of fullerenes for the selective synthesis of specific multi-adducts poses an important challenge. Addition reactions of C60 are well known to occur mainly at the 6,6-bonds (junction between two hexagons) rather than at the 5,6-bonds (junction

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• ) being active at 5 μg/mL, using a 75% cutoff inhibition at each concentration. On the other hand, MCF-7 and SK-MEL-28 cells were the most resistant ones, with no compound being active at the lower concentration (Figure 5). This evidence of selective cytotoxicity for a specific histological tumor subtype

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• compounds. To achieve the selective C–C and C–N bond formation via hydrogen borrowing, controlling the selectivity is an important factor since the formation of possible side-products such as overreduction of unsaturated compounds or dialkylation. Hence, developing an efficient catalyst, capable of

• achieving both selective dehydrogenation and hydrogenation is highly important. A typical BH process is demonstrated in Scheme 1. Several precious transition-metal catalysts have been used successfully in this area, including iridium, rhodium, ruthenium, and osmium [4]. However, these noble metals are toxic

• ). However, N-methylation of anilines with methanol required 100 °C to yield the selective N-methylated products. The same year, Hultzsch et al. designed PN3-pincer ligand-supported Mn(I) complexes for the alkylation of amines with primary and secondary alcohols [42]. Most interestingly, a low catalyst

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• accelerated by enzymes. These enzymes share a similar mechanism of cytosine deamination and a similar tertiary structure. Despite this similarity, individual enzymes are selective for the corresponding cytosine-containing substrates with little or no cross-reactivity. Cytosine deaminase, which is present in

• for inhibition. By changing the nucleotides around dZ (IIc), we obtained the first A3B-selective inhibitor [56]. By inserting the fluoro-substituted FdZ (IId) into ssDNA, we observed three times better inhibition of A3Bctd and wild-type A3A in comparison to the IIc-containing DNA [57], which

• ), 5-methyl-2'-deoxyzebularine and diazepinone 2'-deoxyriboside (IIIb) inserted into loops of DNA hairpins have shown selective inhibition of A3A with a half-maximal inhibitory concentration (IC50) and Ki in the low-nM range [55][60][76][77]. Unfortunately, no inhibition of A3A by the DNA hairpin

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• ) resulted in lower selectivity for the benzyl α,α’-dibromide (2a) compared to 1a or 3a, due to the partial ring bromination [55]. The structure of mesitylene (4), featuring three o,p-activated positions, makes the selective halogenation of benzylic positions even more challenging. The conventional

Mild and efficient synthesis and base-promoted rearrangement of novel isoxazolo[4,5-b]pyridines

• Vladislav V. Nikol’skiy,
• Mikhail E. Minyaev,
• Maxim A. Bastrakov and
• Alexey M. Starosotnikov

Beilstein J. Org. Chem. 2024, 20, 1069–1075, doi:10.3762/bjoc.20.94

• that they do not participate in the stabilization of the pyridine-3-olate anion. It should be noted that the 4-(2-pyridyl)[1,2,3]triazole fragment is part of some pharmaceutically oriented molecules such as tradipitant, an experimental neurokinin-1 receptor antagonist [31], MU1787, a highly selective

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• of amides from 2-alkynylanilines by using TFBen (benzene-1,3,5-triyl triformate) as a CO source, Pd(OAc)2, DPEPhos (bis[(2-diphenylphosphino)phenyl] ether), and DIPEA (N,N-diisopropylethylamine) in MeCN. After 24 h, Pd(OAc)2 and AlCl3 were added to promote a selective cyclization reaction [14]. The

• selective cyclization to the indole derivative in the presence of Pd(OAc)2 and AlCl3. A variety of indole derivatives were synthetized in good isolated yields (Scheme 3). Synthesis of indoles by Pd(II)-catalyzed carbonylation reaction Oxidative carbonylation reactions, as well as all other types of

• targeted products were isolated in good yields (Scheme 5). In 2014, Shen and co-workers developed a selective synthesis for methyl 1-benzyl-1H-indole-3-carboxylates and bis(1-benzyl-1H-indol-3-yl)methanones [18] starting from the same kind of substrates used by Gabriele’s group two years before. The first

Enhancing structural diversity of terpenoids by multisubstrate terpene synthases

• Min Li and
• Hui Tao

Beilstein J. Org. Chem. 2024, 20, 959–972, doi:10.3762/bjoc.20.86

• generate diverse terpene skeletons via sophisticated cyclization cascades. In addition to the many highly selective TSs, there are many promiscuous TSs that accept multiple prenyl substrates, or even noncanonical ones, with 6, 7, 8, 11, and 16 carbon atoms, synthesized via chemical approaches, C

• , indicating that CoTPS5 is highly selective for individual prenyl substrates and that the reaction is tightly regulated under different conditions. Notably, CoTPS5 was the first plant TS to produce 10 [22]. Although many MSTSs exhibit a broad substrate scope in vitro, their product profiles may be altered in

• selective sesqui-TSs failed to transform 104–112. After further modification with cytochrome P450 CYP720B1 in the yeast host, 28 noncanonical terpenoids were generated, 10 of them are shown in Figure 8c (113–122) [58]. Notably, the widespread biosynthesis of C16 terpenoids was reported in a recent study in

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

• followed by a sequential Jones oxidation. The overall method displays a broad scope and good enantioselectivity, favoring the (R) enantiomer. The applicability of the protocol is highlighted by the efficient enantioselective syntheses of the selective phosphodiesterase-4-inhibitor rolipram and the

• Heck adducts (methyl N,O-acetals) were efficiently converted into several arylated γ-lactams by a simple oxidation procedure (Jones oxidation). To demonstrate the applicability of the strategy, two of the chiral aryl-lactams were further derivatized to provide the selective phosphodiesterase-4

• ). Synthesis of (R)-baclofen hydrochloride (6) from 4dd and (R)-rolipram (5b) from 4de To further demonstrate the applicability of this method, the aryl-lactams 4dd and 4de were successfully converted into the selective phosphodiesterase-4 inhibitor (R)-rolipram (5b) [15], and the commercial drug (R)-baclofen

Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents

• Lilian M. Maas,
• Alex Haswell,
• Rory Hughes and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82

• fluorides were also observed as by-products. Given the increasing interest in acyl fluorides in organic synthesis and the attractive features of BT-SRF salts as reagents for organofluorine chemistry, we considered whether optimisation of the reaction conditions could allow for the selective synthesis of

Synthesis and properties of 6-alkynyl-5-aryluracils

• Ruben Manuel Figueira de Abreu,
• Till Brockmann,
• Alexander Villinger,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

• ][42][43][44][45][46][47]. The remaining known methods use only both positions to induce cyclization [25][31][32][33][48][49][50][51][52][53][54][55][56]. Therefore, to the best of our knowledge, there are no known methods that allow the selective reaction of both positions of uracil (Figure 2). In

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

• natural products and pharmaceutical agents, including antifungal drugs [1][2][3], and hence their selective preparation has attracted considerable attention from the synthetic community. Compared to methods for the de novo construction of azole heterocycles, direct functionalization of the azole N–H bond

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• , deiodination at the bridgehead position, and nucleophilic substitution at the alkyl chloride. From 1,2-BCP (±)-4, a variety of 1,2-BCPs were prepared through basic chemical transformations (Scheme 1B) [26]. Selective deprotection gave access to free alcohol-containing 1,2-BCPs (±)-5 and (±)-8. Oxidation and

• -workers reported a method for the selective bridge bromination of BCPs, giving access to brominated 1,2-BCP (±)-16 (Scheme 2) [33]. By exploiting the homolytic cleavage of the C–Br bond using in situ-generated silyl radicals, they were then able to harness the installed bromide functionality in

• development of a new synthetic route to diester 1,2-cubane 88 from dimethyl cubane-1,4-dicarboxylate (85) (Scheme 9A) [51]. 1,4-Cubane 85 is photochemically carboxylated to 86, and selective saponification of the least hindered ester leads to 87. Formation of a redox active ester followed by photocatalytical

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• explored the reactivity of ortho-functionalized diaryliodonium salts containing electron-withdrawing groups (EWGs) such as fluorine and nitro groups [29][30]. These ortho-substituted diaryliodonium salts undergo selective benzocyclizations and arylocyclizations with aromatic acids, leading to 3,4

• investigations demonstrated the ability of diaryliodonium salts for selective mono-arylation of 2-naphthols [34]. In this context, we embark on a strategy to modify the neighbouring position of the diaryliodonium salt with an ester group, presenting a novel copper-catalysed regioselective arylocyclization of

• diaryliodonium salts in a cascade cyclization, the cyclization features a copper-catalyzed activation strategy involving the cleavage of the C–I bond and esterification. The resulting cascade of selective arylation/intramolecular cyclization facilitated the synthesis of 3,4-benzocoumarin derivatives. The

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

• nitramine. An enzyme, N-nitroglycine lyase A (NnlA), from the bacterium Variovorax sp. strain JS1663 (Vs NnlA) was recently shown to degrade NNG. This strain was enriched from sludge from the Holston Army Ammunition Plant using selective growth media containing NNG as the only carbon and nitrogen source [20

• were used to inoculate 100 µL of selective growth media (1/5 LB media, 20 µM isopropyl β-ᴅ-thiogalactopyranoside (IPTG), 300 µM 2-NAE or 3 mM NNG, and antibiotic) in a 96-well plate. After overnight incubation at 37 °C, the cells were pelleted by centrifugation and the nitrite quantified by Griess

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• ]octane, while O6 migrated when the C4–OH was axial leading to 2,4-dioxabicyclo[2.2.2]octanes. The formation of both anomers from the non-selective addition of fluoride suggested intermediates with oxocarbenium character. This work has recently been extended by Banwell and co-workers to include a set of

• reduction using NaBH4 as per our previously published approach (Scheme 1) [9]. When α-alkylations are performed using 2, the second alkylation step is faster than the first, meaning that only the dialkylated products are formed [16], and the reduction is highly selective with approach of the reductant from

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• distillation [41]. Under these conditions, exclusive formation of the bis-hydrochlorinated product (not shown) might have been anticipated. Several examples of the hydrochlorination of more complex molecules were reported (Scheme 5). Torii demonstrated the selective formation of chloride 20 when treating enone

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• single pentafluorophenyl ring was prepared through the regioselective nucleophilic aromatic substitution reaction of the p-fluorine atoms in 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin with 9-mercapto-m-carborane. The reaction of this porphyrin with sodium azide led to the selective substitution of

• biomolecules via the nucleophilic aromatic (SNAr) substitution reactions [15][16]. A variety of nucleophiles such as amines [17][18], alcohols [18][19][20], thiols [17][19][21][22][23], and carboranes [17][24][25][26][27] have been studied in selective SNAr substitution reactions of the p-fluorine atoms in

• has become one of the most popular route for the site-selective modification of cysteine residues in bioconjugation technology. We suppose that the maleimide group in porphyrin 11 is a useful target for thiol conjugation via Michael addition reactions [44]. This also concerns biotin-conjugated organic

Methodology for awakening the potential secondary metabolic capacity in actinomycetes

• Shun Saito and
• Midori A. Arai

Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69

• therapeutic drugs [1], agrochemicals [2], veterinary medicines [3], medium supplements for selective microbial/cell culture [4][5][6], food preservatives/colorings [7][8], and biochemical reagents for pharmacological/chemical biology studies [9]. This review has focused particularly on compounds produced by