Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• derivatives 3 in yields up to 99%, up to 20:1 dr, and up to 99% ee [24]. This work represents the first enantioselective bifunctional catalytic inverse electron demand Diels–Alder reaction that occurs with a dual control of the dienophile HOMO and diene LUMO energies of the substrates. The amino group of the

Ceratinadin G, a new psammaplysin derivative possessing a cyano group from a sponge of the genus Pseudoceratina

• Shin-ichiro Kurimoto,
• Kouta Inoue,
• Taito Ohno and
• Takaaki Kubota

Beilstein J. Org. Chem. 2024, 20, 3215–3220, doi:10.3762/bjoc.20.267

• -labeled ʟ-phenylalanine [19]. Therefore, the cyano group in bromotyrosine alkaloids containing the phenylacetonitrile moiety is derived from the α-carbon and amino group of ʟ-tyrosine. On the other hand, the biosynthesis of nitrile with a cyanoformamide moiety remains unclear. Ceratinadin G (1) represents

Discovery of ianthelliformisamines D–G from the sponge Suberea ianthelliformis and the total synthesis of ianthelliformisamine D

• Sasha Hayes,
• Yaoying Lu,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2024, 20, 3205–3214, doi:10.3762/bjoc.20.266

• cluster at m/z 477/479/481 [M + H]+. Similarly to compound 4, the 1H NMR (Table 1) and edited HSQC spectra of 5 displayed six methylene signals (δH 3.25, 2.92, 2.36, 1.79, 1.77). Additionally, a broad exchangeable proton (δH 8.35) was observed that was indicative of a protonated dialkylated amino group [7

• integrated for three protons and a triplet (δH 8.23) that were indicative of a protonated terminal amino group and a secondary amide functionality, respectively [7]. 13C NMR shifts and COSY correlations associated with the methylene signals of 7 enabled the assignment of an NH–(CH2)3–NH2 moiety, which was

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• produce simple structured rotaxane species (Scheme 3) [46][47][48]. In this method, dodecanediamine and α-CD are mixed in water to form a pseudo[3]rotaxane (1), and the subsequent one-pot end-capping reaction driven by the amino group on the axle ends and substituted phenyl isocyanate produced [3]rotaxane

Tunable full-color dual-state (solution and solid) emission of push–pull molecules containing the 1-pyrindane moiety

• Anastasia I. Ershova,
• Sergey V. Fedoseev,
• Konstantin V. Lipin,
• Mikhail Yu. Ievlev,
• Oleg E. Nasakin and
• Oleg V. Ershov

Beilstein J. Org. Chem. 2024, 20, 3016–3025, doi:10.3762/bjoc.20.251

• group, a strong blue shift occurred down to 394 nm. The only exception was a solution of 1i in acetic acid, where two peaks were observed. Apparently, the weaker acetic acid caused just a partial protonation of the amino group, and the equilibrium shown in Scheme 2 was observed. This was evidenced by

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

• this Li and Jiang, created an effective ball-milling process for the N-arylation of amines 38 with the assistance of diaryliodonium salts 16 (Scheme 15) [67]. The arylation of an amino group or nitrogen heterocycle occurred effectively when the reaction is performed under solvent-free conditions or

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

• -acylamine; oxazole; propargylamine; Introduction Propargylamine is an important motif in the synthesis of heterocyclic compounds [1][2][3][4] and drug discovery [5][6] due to its multifunctionality, which includes a basic and nucleophilic amino group, an electrophilic and dipolarophilic triple bond, and an

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

• -nitrogen atom. The second route involves the participation of an amino group which allows the formation of adducts 7 and 9 (routes A2 and B2). The intermediates formed then undergo subsequent tandem recyclization of succinimide/citraconimide fragments at the expense of one of the carbonyl groups and the

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

• the reaction protonates the amino group, making the final cyclization less efficient. Finally, we have tried to extend the synthetic protocol to other benzo-fused N-heterocycles. We investigated the benzo-fused 7-membered nitrogen heterocycles, both for our previous experience in applying them in MCRs

Synthesis of fluoroalkenes and fluoroenynes via cross-coupling reactions using novel multihalogenated vinyl ethers

• Yukiko Karuo,
• Keita Hirata,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 2691–2703, doi:10.3762/bjoc.20.226

• 5l) could be introduced into 1a in 76% or 52% yields, respectively (Table 4, entries 10 and 11). Reactions using acetylenes possessing a hydroxy group, amino group and thiophene proceeded well (3m–o) (Table 4, entries 12–14). Hexa-1-yne 5p and cyclopropylacetylene (5q) afforded 3p and 3q

• -coupling between 1 derived from various phenols and 5a. Vinyl ethers 1b–d were converted into enynes 3t–v in 29–35% yields (Table 4, entries 19–21). The reaction using 1e, which bears an amino group on the benzene ring, did not complete despite requiring a long reaction time (Table 4, entry 22). Therefore

Photoluminescence color-tuning with polymer-dispersed fluorescent films containing two fluorinated diphenylacetylene-type fluorophores

• Kazuki Kobayashi,
• Shigeyuki Yamada,
• Motohiro Yasui and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2682–2690, doi:10.3762/bjoc.20.225

• as electron-donating groups was shown to promote intramolecular charge transfer (ICT) and shifted the PL wavelength to longer wavelengths, resulting in yellow or orange fluorescence in the solid state [21][22]. In addition, cross-linking between the amino group and attached benzene ring effectively

Efficient modification of peroxydisulfate oxidation reactions of nitrogen-containing heterocycles 6-methyluracil and pyridine

• Alfiya R. Gimadieva,
• Yuliya Z. Khazimullina,
• Aigiza A. Gilimkhanova and
• Akhat G. Mustafin

Beilstein J. Org. Chem. 2024, 20, 2599–2607, doi:10.3762/bjoc.20.219

• the amino group is involved in the formation of an intermediate hydroxylamine derivative. Scheme 3 demonstrates a possible reaction mechanism using the example of the peroxydisulfate oxidation of MU and TMU catalyzed by PcM. It is proposed that PcM provides the necessary polarization of peroxydi(mono

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• product, although in this case, reduction of the nitro group to an amino group was observed and the resulting 4-aminobenzaldehyde is likely too electron-rich to undergo allylation. The use of other halides was also explored (Table 3). Switching to allyl chloride (Table 3, entry 2) did result in partial

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

• the possible substitution patterns, meta-substituted anilines hold a special place. These compounds are difficult to access due to the inherent ortho-/para-directional reactivity of the amino group, at the same time they are widely used in medicinal chemistry, resulting in several marketed drugs

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

• with IC50 values of 25.5 and 37.3 μM, respectively [171], and exhibited significant larvicidal activity against Aedes aegypti (LC50: 7.2 μg/mL) [172]. Pestauvicolactone A (30) bearing an amino group in position C-4 of dimethylated alternariol was isolated from Pestalotiopsis uvicola [174]. It was

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• derivatives 29–31 were immobilised on this polymer support by utilising its reactive epoxy groups (Scheme 9). These structurally diverse precatalysts were prepared by modifying the cinchona skeleton at different positions to investigate how the amino group-containing linker affects them. The immobilised

• . α-Amination of ethyl 2-oxocyclopentanecarboxylate catalysed by PS-THU which could be recycled over 9 reaction cycles. Preparation of supported catalysts C29–C31 from cinchona squaramides 29–31 modified with a primary amino group. Application of PGMA-supported organocatalysts C29–C31 in the

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• continuous flow conditions, leading to reaction completion within 30 minutes (Scheme 4). Oxime formation Once the ethyl heteroarylacetates scope was completed we turned our attention to the incorporation of the amino group. There are precedents for α-aminations, but we were not able to find a method suitable

• amino group by reduction. We reasoned that increasing the sp2 fraction and the rigidity of the whole structure will lead to increased stability of these derivatives. The first exploratory attempts demonstrated the easy preparation and the high bench stability of the oxime derivatives, therefore we opted

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• multistep procedure, however, by employing 3,6-diamino-1,2,4-triazin-5-one 44 as amidine derivative, 46 could be simply obtained through a GBB-3CR. The amino group in position 3 was opportunely protected to drive the GBB reaction to the selective formation of 45. Microwave heating appeared to be beneficial

Harnessing unprotected deactivated amines and arylglyoxals in the Ugi reaction for the synthesis of fused complex nitrogen heterocycles

• Javier Gómez-Ayuso,
• Pablo Pertejo,
• Tomás Hermosilla,
• Israel Carreira-Barral,
• Roberto Quesada and
• María García-Valverde

Beilstein J. Org. Chem. 2024, 20, 1758–1766, doi:10.3762/bjoc.20.154

• hurdles. Here, we have demonstrated the possibility of using the combination of arylglyoxals and carboxylic acids tethered to nonprotected deactivated amines as a powerful strategy for the synthesis of complex fused heterocycles. The limited nucleophilic character of the amino group of the anthranilic

• protecting groups, as the reduced nucleophilic character of the amino group of the anthranilic acid would prevent its participation in the Ugi reaction. In this way, the Ugi reaction was performed using arylglyoxals 1, anthranilic acid derivatives 2, amines 3 and isocyanides 4 following the most common

• assayed in our group. Under these conditions, the bis-1,4-benzodiazepines 7 resulting from the reaction of the amino group with the imine on the benzodiazepine were obtained as a single diastereomer. On the basis of the preferred conformation for the 1,4-benzodiazepin-5-ones 5 and 6 [20][22], where the

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• revealed that compounds derived from estrone were more potent than those from trans-androsterone. Additionally, spiro 2-aminooxazolines were identified as the most active compounds in both series. Notably, when considering the substituent on the amino group, butyl and cyclohexyl derivatives displayed

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• -methylation concurrently to peptide synthesis is also possible. Commonly used methods for SPPS of N-methylated peptides involve activating the amino group with 2-nitrobenzenesulfonamide and methylating agents, such as dimethyl sulphate [40][41][42]. Directly methylating peptides is challenging. Multiple amide

• -terminal methyltransferases The α-amino group of N-terminal amino acid residues can either be mono-, di-, or trimethylated. This methylation step occurs after the core peptide is cleaved from the leader and can enhance the metabolic stability of the final peptide natural product [85]. Crocagin A is the

Synthesis of 2-benzyl N-substituted anilines via imine condensation–isoaromatization of (E)-2-arylidene-3-cyclohexenones and primary amines

• Lu Li,
• Na Li,
• Xiao-Tian Mo,
• Ming-Wei Yuan,
• Lin Jiang and
• Ming-Long Yuan

Beilstein J. Org. Chem. 2024, 20, 1468–1475, doi:10.3762/bjoc.20.130

• reduction. This electrophilic aromatic substitution usually needs harsh reaction conditions, tedious synthetic procedures and sometimes encounters the trouble of separating positional isomers caused by orientation or steric effects of the pre-existed amino group on the aryl moiety. Nevertheless, anilines

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• applications have been developed. In the future, it will be interesting also to study reactions of 3-nitrochromone with carbonyl compounds. In this context, biological properties of the products will be interesting, as the nitro group can be transformed to the biologically important amino group. Structures of

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• ). Similar to the 77Se NMR signals of isomeric diaryl diselenides 1 and 2, the symmetrical diaryl diselenide 12, having an amino group para to the selenium center in both aryl units, showed a downfield shift compared to isomer 11. The mass spectrum of oxamide 13 revealed peaks for the sodium complexes [M

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

• bearing a secondary amino group and an internal triple bond [16]. In the same research group, it has been demonstrated that with a terminal alkynyl group, the reactivity is completely different leading to the formation of dihydroindol-2-one derivatives [17]. The process was versatile and efficient towards

• presence of trimethyl orthoformate to transform, in situ, the primary amino group into a secondary amino group with an easy-to-remove substituent thus performing a not direct synthesis process. Indeed, the desired N–H-free product was obtained by acidic treatment of the reaction crude. In both cases, the

• ) species and the triple bond that promotes an intramolecular nucleophilic attack of the amino group giving a indolcyclopalladium species. This is followed by CO insertion and intramolecular nucleophilic displacement by the hydroxy group to give the indole–PdII-cycle derivate. The reaction ends with a