Synthesis of the 1,5-disubstituted tetrazole-methanesulfonylindole hybrid system via high-order multicomponent reaction

• Cesia M. Aguilar-Morales,
• América A. Frías-López,
• Nadia V. Emilio-Velázquez,
• Alejandro Islas-Jácome,
• Angelica Judith Granados-López,
• Jorge Gustavo Araujo-Huitrado,
• Yamilé López-Hernández,
• Hiram Hernández-López,
• Luis Chacón-García,
• Jesús Adrián López and
• Carlos J. Cortés-García

Beilstein J. Org. Chem. 2024, 20, 3077–3084, doi:10.3762/bjoc.20.256

• trifluoroethanol as the solvent and at room temperature [23][24][25][26]. In the initial reaction, propargylamine served as a bifunctional reagent, with the primary amine group participating in the first step and the terminal alkyne promoting the subsequent heteroannulation. (Scheme 2). As observed in our previous

Enantioselective regiospecific addition of propargyltrichlorosilane to aldehydes catalyzed by biisoquinoline N,N’-dioxide

• Noble Brako,
• Sreerag Moorkkannur Narayanan,
• Amber Burns,
• Layla Auter,
• Valentino Cesiliano,
• Rajeev Prabhakar and
• Norito Takenaka

Beilstein J. Org. Chem. 2024, 20, 3069–3076, doi:10.3762/bjoc.20.255

• quenching with aqueous NaOH or NaHCO3 solutions. Results and Discussion Our group recently reported that N,N-diisopropylethylamine required for the synthesis of propargyltrichlorosilane isomerized it to allenyltrichlorosilane in the absence of solvents, and that removal of the amine before the distillation

• prevent a direct Si–N interaction. From Rprop, the amine group of N,N-diisopropylethylamine abstracts the H1 proton with a barrier of 14.2 kcal/mol to form an intermediate (IN1). The intermediate IN1 is unstable (endergonic by 14.0 kcal/mol) and will immediately stabilize to another intermediate (IN2

Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond

• Thomas Ma and
• John Chu

Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253

• to fully understand the determinant(s) of NRP topology. There are many ways to classify NRPs when topology and chemical structural features are considered simultaneously. For example, a macrocycle may be a lactam or a lactone depending on whether the internal nucleophile is an amine or an alcohol

Tailored charge-neutral self-assembled L₂Zn₂ container for taming oxalate

• David Ocklenburg and
• David Van Craen

Beilstein J. Org. Chem. 2024, 20, 3007–3015, doi:10.3762/bjoc.20.250

• ligand resulted in no clean formation of a charge-neutral metallocontainer with zinc(II) acetate. We believe that the modification with benzoyl chloride does not only alter the solubility but also shields the secondary amine which might act as additional coordination site. Binding of monocarboxylate

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• proposed mechanism of amine 72 peroxidation is the oxidation of Cu(I) with TBHP, resulting in the formation of tert-butoxy radical A, which abstracts the hydrogen atom from substrate 72 to form the C-centered radical B. The generated Cu(II) oxidizes TBHP to form tert-butylperoxy radical C, which recombines

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• group with a less hindered portion is observed. The mechanism revealed the reaction undergoes the homolytic cleavage of the diaryliodonium salt to produce an iodoaryl radical cation, which further reacts with the amine to acquire the corresponding diaryl amines. Moreover, a similar reaction tried with a

• diaryliodonium salts 40 (Scheme 18) [69], which however, does not produce the diarylated compounds. The intramolecular aryl migration from the iodine to the nitrogen leads to a quaternary ammonium ion intermediate A. Consequently, a nucleophilic ring opening of cyclic amine in 42 occurred via cleavage of the

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• -glycoside 11a (Scheme 7) [20]. Debenzylation gave product 11b which was transformed to akashin A (11c) by reduction of the azide to the amine in the presence of propane-1,3-dithiol and subsequent debenzoylation. Akashin A was transformed to akashins B and C by acetylation and reaction with diacetyl

• -mannose (14) afforded indigo-N-mannoside α-15a, albeit, in low yield (Scheme 11) [21]. Deacetylation afforded product α-15b. Indirubin-N-glycosides (red sugars) In contrast to indigo, indirubin is a non-symmetrical compound containing an amine- and an amide-type nitrogen atom. In our group, we developed a

• -glycosides containing the carbohydrate moiety located at the amine-type nitrogen atom (Scheme 18) [25]. For this purpose, we decided to react isatins with N-glycosylated indoxyls which were entirely unknown at that time. The reaction of ʟ-rhamnose α/β-4c with indoline afforded α/β-25a (β:α ≈ 4:1

Multicomponent synthesis of α-branched amines using organozinc reagents generated from alkyl bromides

• Baptiste Leroux,
• Alexis Beaufils,
• Federico Banchini,
• Olivier Jackowski,
• Alejandro Perez-Luna,
• Fabrice Chemla,
• Marc Presset and
• Erwan Le Gall

Beilstein J. Org. Chem. 2024, 20, 2834–2839, doi:10.3762/bjoc.20.239

• 16 h at 80 °C (Table 1, entry 2). However, its suitability in the multicomponent coupling with an amine and an aldehyde still had to be demonstrated as there was no precedent for such a Mannich multicomponent coupling involving nonstabilized organozinc halides using THF or 2-MeTHF as solvent. To our

• species 2 were collected using a syringe and allowed to react with an amine 3 and an aldehyde 4 under moderate heating (Scheme 2). The multicomponent couplings proceeded smoothly, with an acceptable yield of the α-branched amine being obtained after 3 h at 50 °C. A range of secondary amines as well as

• various aromatic aldehydes could be used in the multicomponent coupling. Interestingly, functionalized organozinc reagents gave the multicomponent coupling product, except for the cyanated organozinc compound 2d, which only provided traces of the expected α-branched amine. It can be noted that in sharp

Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

• Kento Iwai,
• Akari Hikasa,
• Kotaro Yoshioka,
• Shinki Tani,
• Kazuto Umezu and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

• anhydride, the intermediately formed hemiacetal underwent acetylation, leading to N,O-acetals 1. In this method, an acid amide can be used as an amine masked with an acyl group. Subsequent elimination of acetic acid occurred to afford 2 in situ upon treatment with a base, enabling nucleophilic addition with

• nucleophiles to synthesize PCPAs, and their ring closures were also investigated. Results and Discussion NAI 2 can be generated by treating N,O-acetal 1 with a base, such as triethylamine. However, the addition of an amine was omitted because lithium acetylide functions both as nucleophile and base. When 1a

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• , highly sensitive chemosensors via a facile synthetic route/method, we have explored three chelates for lanthanide ions (DO3A, 2,6-pyridinedicarboxylic acid and DO2A), resulting in complexes with different overall charges. Additionally we have explored two copper(II) binding groups (di(2-picolyl)amine and

Synthesis and antimycotic activity of new derivatives of imidazo[1,2-a]pyrimidines

• Dmitriy Yu. Vandyshev,
• Daria A. Mangusheva,
• Khidmet S. Shikhaliev,
• Kirill A. Scherbakov,
• Oleg N. Burov,
• Alexander D. Zagrebaev,
• Tatiana N. Khmelevskaya,
• Alexey S. Trenin and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2024, 20, 2806–2817, doi:10.3762/bjoc.20.236

• , it is worth mentioning the work of Li and co-workers (2011) [20], who described a single example of the formation of such structures by carrying out an organocatalytic domino aza-Michael–Mannich reaction between benzylidene-1H-imidazol-2-amine and cinnamaldehyde. Although the imidazo[1,2-a

Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction

• Yuta Kabumoto,
• Eiichiro Yoshimoto,
• Bing Xiaohuan,
• Masato Morita,
• Motohiro Yasui,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2776–2783, doi:10.3762/bjoc.20.233

• amides in moderate three-step yields. Keywords: amine; chirality transfer; [1,3]-proton shift reaction; tetrafluoroethylene fragment; Introduction A fluorine atom has quite peculiar chemical and physical properties compared to others, and hence changes in molecular properties resulting from the

• 22b could not be completely suppressed. The thus obtained [1,3]-proton shift product (S)-20b was subjected to 2 N HCl aq in Et2O for 2 h, and subsequently 2 N NaOH aq, affording the corresponding free amine (S)-17b. Then, treatment of the amine with CbzCl and pyridine in CH2Cl2 gave the corresponding

• good yield and a high asymmetric transfer was achieved. As a result, it was found that various optically active amine derivatives could be obtained with high optical purity. Various applications of tetrafluoroethylenated molecules. Precedent synthetic approaches to optically active compounds possessing

Copper-catalyzed yne-allylic substitutions: concept and recent developments

• Shuang Yang and
• Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

• :1 (Scheme 3, 3e). Carbonates with aryl or styryl residue can undergo the reaction smoothly (Scheme 3, 3f–k), but alkyl-substituted substrates showed low yields (Scheme 3, 3l and 3m). Moreover, secondary amines with various substituents, acyclic amines, primary amines, or even the amine moieties in

• et al. [63][64] reported the first amine-mediated highly enantioselective copper-catalyzed asymmetric yne-allylic substitution, affording 1,4-enynes with up to 98% ee and >20:1 rr. A series of secondary amines can react smoothly and achieve good enantioselectivities and regioselectivities (Scheme 7

• ). Further control experiments and DFT calculations show that during the catalytic process, tertiary amine directly participates as a nucleophilic reagent to give the ammonium salt, which then releases dimethylaminium to provide the final product (Scheme 12). Chiral allylic sulfone compounds can be easily

Synthesis of spiroindolenines through a one-pot multistep process mediated by visible light

• Francesco Gambuti,
• Jacopo Pizzorno,
• Chiara Lambruschini,
• Renata Riva and
• Lisa Moni

Beilstein J. Org. Chem. 2024, 20, 2722–2731, doi:10.3762/bjoc.20.230

• Scheme 6. Based on the results reported by Zeitler [28], several mechanisms are involved in the oxidation of N-Ph-THIQ. The most probable involves the photoexcitation of the EDA (Electron Donor-Acceptor) complex promoting an electron transfer from N-Ph-THIQ to BrCCl3 to afford the amine radical cation

Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones

• Ruben Manuel Figueira de Abreu,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228

• when located at position 5 of the uracil ring, which might be due to the protonation of the amine under the employed reaction conditions, making the aryl ring less feasible for the SEAr reaction (Scheme 4b). The same effects may explain the cyclisation of 4f to 5f, while 4c is not converted to the

Computational design for enantioselective CO₂ capture: asymmetric frustrated Lewis pairs in epoxide transformations

• Maxime Ferrer,
• Iñigo Iribarren,
• Tim Renningholtz,
• Ibon Alkorta and
• Cristina Trujillo

Beilstein J. Org. Chem. 2024, 20, 2668–2681, doi:10.3762/bjoc.20.224

• regioselectivity of the CO2 insertion into PO must be addressed as part of the full mechanistic investigation. The compound 3-boryl-2-propen-1-amine is now considered as the catalyst (Figure 2B). As observed in Figure 2A, the bond length and electron density at the bond critical point (BCP) difference are minimal

Synthesis and cytotoxicity studies of novel N-arylbenzo[h]quinazolin-2-amines

• Battini Veeraiah,
• Kishore Ramineni,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Hélène Solhi,
• Rémy Le Guevel,
• Chada Raji Reddy,
• Frédéric Justaud and
• René Grée

Beilstein J. Org. Chem. 2024, 20, 2592–2598, doi:10.3762/bjoc.20.218

• ]quinazolin-2-amine (3): To a stirred solution of guanidinium carbonate (2.0 g, 0.011 mol) in DMA (15 mL) was added compound 2 (1.5 g, 0.008 mol). Then the reaction mixture was heated to stir at 150 °C for 16 h. After completion of the reaction (TLC), the mixture was poured into ice water, a solid was formed

• ; HRESIMS (m/z): [M + H]+ calcd for C12H10N3,196.0869; found, 196.0872 (1 ppm); mp: 193–195 °C (lit. 194–196 °C [12]). Step 3: Representative procedure for the preparation of compounds 4: To the stirred solution of benzo[h]quinazolin-2-amine (3a, 0.256 mmol, 1.0 equiv) in 1,4-dioxane (4 mL) was added

• ). Compound 4a: N-phenylbenzo[h]quinazolin-2-amine: 69% yield (off white solid). 1H NMR (400 MHz, DMSO-d6, δ ppm) 10.01 (br s, 1H, NH), 9.29 (s, 1H), 9.03 (dd, J = 7.2, 0.8 Hz, 1H), 8.07–8.01 (m, 3H), 7.84–7.72 (m, 3H), 7.43 (d, J = 2.0 Hz, 1H), 7.41 (t, J = 7.6 Hz, 1H), 7.05 (t, J = 6.8 Hz, 1H); 13C NMR (75

Base-promoted cascade recyclization of allomaltol derivatives containing an amide fragment into substituted 3-(1-hydroxyethylidene)tetronic acids

• Andrey N. Komogortsev,
• Constantine V. Milyutin and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 2585–2591, doi:10.3762/bjoc.20.217

• refluxing EtOH allowed us to obtain substituted enehydrazine 7 (Scheme 5a). The similar condensation with amine 8 led to enamine derivative 9 (Scheme 5b). Based on the data of X-ray analysis compound 7 has the same configuration of double and hydrogen bonds as in the case of starting tetronic acids 4

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• the DDQH• radical to generate a carbocation and DDQH−. In path B, the reaction involves direct hydride transfer to DDQ, forming DDQH− and a carbocation. In both pathways, the amine nucleophile captures the carbocation, resulting in the final amination product after losing a proton. Subsequently, DDQH

• mediator between the anode and the nickel-chelated enolate intermediate. Simultaneously, the amine substrate is oxidized at the anode and deprotonated to generate a nitrogen-centered radical. The desired product then is generated by the stereoselective cross-coupling of the carbon-centered radical with the

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• as a key methodology in the synthesis of alkaloids and natural products with 4-, 5- and 6-membered cyclic amine motifs. Initially reliant on stoichiometric reagents, synthetic chemists predominantly used N-substituted chiral imines, organometallic chiral reagents and achiral reagents with an

• directly prepared by combining three readily accessible synthons: an amine, an allyl nucleophile, and a carbonyl compound (Scheme 1) [15][16]. A selection of structural motifs accessible via homoallylic amines is shown in Scheme 1. Despite several reviews on homoallylic amine syntheses being published [17

• (Scheme 6). The study explored a broad range of p-methoxyphenyl (PMP)imines derived from aryl, heteroaryl and alkyl aldehydes (including ethyl glyoxylate), demonstrating yields of 57–98% and high enantioselectivity of 90–98%. Screening of aldehyde and amine components indicated that the method is

Improved deconvolution of natural products’ protein targets using diagnostic ions from chemical proteomics linkers

• Andreas Wiest and
• Pavel Kielkowski

Beilstein J. Org. Chem. 2024, 20, 2323–2341, doi:10.3762/bjoc.20.199

• . The fragmentation of the triazole ring leaving the primary amine and b-ion resulting from the fragmentation of the TEV-recognition peptide sequence. The chemical cleavage of the linker to release probe–peptide conjugates is achieved mainly by the change of the pH or via reducing conditions to release

Stereoselective mechanochemical synthesis of thiomalonate Michael adducts via iminium catalysis by chiral primary amines

• Michał Błauciak,
• Dominika Andrzejczyk,
• Błażej Dziuk and
• Rafał Kowalczyk

Beilstein J. Org. Chem. 2024, 20, 2313–2322, doi:10.3762/bjoc.20.198

• studies by Bolm [12][13], and Juaristi et al. [14]. have significantly advanced chiral secondary amine-catalyzed stereoselective reactions under ball milling conditions, representing a widely explored activation mode in mechanochemical-mediated transformations. However, reports on chiral primary iminium

• [15][16] or iminium-ion catalysis [17] under ball-mill conditions are scarce, in contrast to the abundance of transformations catalyzed by such covalent catalysis. Among the numerous organocatalytic reactions facilitated by primary amine-based iminium ions, Michael-type additions deserve special

• by extended reaction times, sometimes up to 168 hours. An intriguing example involves the use of a bifunctional primary amine-sulfonamide catalyst, which activates benzylideneacetone towards dibenzyl malonate, with the presence of water accelerating the reaction [25]. An alternative approach, where

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

• including pyrimidines and pyrazines. The importance of mechanistic understanding for model building was underlined by Kuang et al. [126], where the authors considered multi-catalyst enantioselective reactions, where one catalyst was an organocatalyst, either CPA or an amine. The co-catalyst was included in

• expands the considerable reaction space in organocatalysis. The discussed principle of mechanistic transferability has also been employed outside of CPA catalysis, with a focus on amine-based hydrogen-bond donors, for example imidodiphosphorimidate-type catalysts for the construction of THF and THP rings

• for this reaction class (ee threshold 80%), even though amine-based catalysts demonstrate a higher average ee. Notably, this strategy is not restricted to literature-extracted examples and can also be applied to enantioselectivities calculated via quantum chemical calculations or predictions from an

Deuterated reagents in multicomponent reactions to afford deuterium-labeled products

• Kevin Schofield,
• Shayna Maddern,
• Yueteng Zhang,
• Grace E. Mastin,
• Rachel Knight,
• Wei Wang,
• James Galligan and
• Christopher Hulme

Beilstein J. Org. Chem. 2024, 20, 2270–2279, doi:10.3762/bjoc.20.195

• method to prepare [D1]-formamides (D–C=O) is through a Leuckart–Wallach reaction with an amine and [D1]-methyl/ethyl formate or [D1]-dimethylformamide [19][20]. Stockmann and co-workers produced [D2]-formamides (N–D, D–C=O) via acid-catalyzed nitrile hydrolysis with HCl and D2O [21]. Thus, using the

• scope of reactivity and determination of deuterium retention using a combination of deuterated aldehydes, [D1]-, and/or [D2]-isocyanides. We began with the venerable Ugi 4-component reaction (Ugi-4CR), first reported by Ivar Ugi in 1959 [28]. The Ugi-4CR utilizes an amine, carbonyl, carboxylic acid, and

• is comprised of reaction of an isonitrile, amine, and aldehyde/ketone, in the presence of phenylphosphinic acid (PPA), to give α-amino amides [35]. Examples of deuterated Ugi-3CR products are represented in Scheme 4. Like the Ugi 4-CR reaction, there was no deuterium scrambling in the Ugi 3-CR. Using

Heterocycle-guided synthesis of m-hetarylanilines via three-component benzannulation

• Andrey R. Galeev,
• Maksim V. Dmitriev,
• Alexander S. Novikov and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2024, 20, 2208–2216, doi:10.3762/bjoc.20.188

• was released [57] allowing direct comparison of different substituents. On the basis of the calculated Hammett constants, we have selected a model series of 1,3-diketones, bearing heterocyclic substituents with a range of electron-withdrawing ability (Figure 2). For the amine model series, we used

• amines with different nucleophilicity, namely benzylamine (primary alkylamine), morpholine (secondary alkylamine) and aniline (aromatic amine). We first examined the reaction of 1,2,4-oxadiazole-1,3-diketone 1a (σm/σp 0.463/0.575, which is quite close to the constants of the CO2Me group, so a successful

• reaction in the presence of molecular sieves and 1.5-fold excess of aniline (conditions B) dramatically reduced the reaction time to 1 d, allowing isolation of diarylamine 3ac in 75% yield (Scheme 2). Next, we started to screen various heterocyclic 1,3-diketones with the model amine series. The reaction of