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

• introduces primary amines for 1,3-dipolar cycloaddition which is less explored due to the probability of competitive Strecker degradation over decarboxylation of azomethine ylides. The protocol reveals the efficiency of MW assisted reaction with reduced reaction time from 18 h to 12 min and enhanced the

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• -amine (5f, 80%), cyclohexylamine (5d, 85%), and also with the 4-CF3 and 4-OMe-benzylamines (5g, 85%; 5h, 65%). Additionally, when using primary amines in the reaction the formation of polysubstituted products was not observed. On the other hand, N-phenylpyridin-2-amine afforded the appropriate compound

Three-component reactions of aromatic amines, 1,3-dicarbonyl compounds, and α-bromoacetaldehyde acetal to access N-(hetero)aryl-4,5-unsubstituted pyrroles

• Wenbo Huang,
• Kaimei Wang,
• Ping Liu,
• Minghao Li,
• Shaoyong Ke and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2920–2928, doi:10.3762/bjoc.16.241

• , aliphatic primary amines and ammonia, such as benzylamine and N-butylamine, were also examined as nitrogen donors; however, no desired product was detected. Then, we attempted to synthesize pharmaceutically active N-heterocyclic pyrrole derivatives with the aid of this three-component reaction. To our great

One-pot multicomponent green Hantzsch synthesis of 1,2-dihydropyridine derivatives with antiproliferative activity

• Giovanna Bosica,
• Kaylie Demanuele,
• José M. Padrón and
• Adrián Puerta

Beilstein J. Org. Chem. 2020, 16, 2862–2869, doi:10.3762/bjoc.16.235

• source of nitrogen has also been varied from the classical use of ammonia. The most common nitrogen source reported in literature is ammonium acetate (3). Others include the use of oxahydrazines, primary amines, and urea. The oxidation of dihydropyridines to pyridines has been achieved using mild

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor

• Dalel El-Marrouki,
• Sabrina Touchet,
• Abderrahmen Abdelli,
• Hédi M’Rabet,
• Mohamed Lotfi Efrit and
• Philippe C. Gros

Beilstein J. Org. Chem. 2020, 16, 1722–1731, doi:10.3762/bjoc.16.144

• construction of nitrogen-containing heterocycles from common substrates: 1,4-diketones and primary amines. Indeed, by just varying the substrates, the substituents, or the heating mode, it is possible to selectively synthesize indole, indolone (1,5,6,7-tetrahydroindol-4-one), or cinnoline (5,6,7,8

• indole, indolone, or cinnoline derivatives from the same starting material is not yet available. To reach this goal, the Michael reaction between 1,4-diketones and primary amines seems particularly attractive because of its straightforward and metal-free properties, and because they can be performed

• ; indoles 6, indolones 7, and cinnolines 8, starting from common substrates 1,4-diketones 5 and primary amines. The protocols developed here used mild conditions, were functional-group tolerant, transition-metal-free, proceeded in moderate to good yield, and could therefore easily be used in medicinal

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• oxidation of amines to imines was also described using heterogeneous catalysis. Zhang and co-workers demonstrated that the MOF (SnIV)porphyrin-containing photocatalyst (UNLPF-12) can be used for the oxidation of primary amines to imines in 88–99% yields under visible light irradiation (Scheme 53) [40]. In

• this case, the authors observed the oxidative coupling between the primary amines and their respective imines to produce the secondary imines. Wang and co-workers reported the synthesis, characterization, and application of interesting metal-free heterogeneous photocatalysts, 2D porphyrin-COFs (Por-COF

• methodology (conditions A). However, when primary amines were used, the authors observed an oxidative coupling between the amines and their respective N-substituted imines, which were trapped with TMSCN to afford the corresponding nitriles. The authors solved this problem by cooling the reaction to −50 °C and

Photocatalytic deaminative benzylation and alkylation of tetrahydroisoquinolines with N-alkylpyrydinium salts

• David Schönbauer,
• Carlo Sambiagio,
• Timothy Noël and
• Michael Schnürch

Beilstein J. Org. Chem. 2020, 16, 809–817, doi:10.3762/bjoc.16.74

• from amino acids gave a complex reaction mixture, and the desired products could not be isolated. Additionally, alkyl salts derived from primary amines were unreactive. For the more stable allyl radicals, our initially optimized conditions with [Ru(bpy)3]Cl2 in DMA/ACN were again applicable and the

Exploring the scope of DBU-promoted amidations of 7-methoxycarbonylpterin

• Anna R. Bockman and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2020, 16, 509–514, doi:10.3762/bjoc.16.46

• amines screened to react. This preliminary screen of amines gave acceptable yields for a range of substituted amines, with primary amines often giving the best results, as expected. To streamline the amine screening and allow for better comparisons of reactivity, a variety of times and temperatures were

• smoothly reacted affording product 9 in good yield under reaction conditions identical to those for the unhindered primary amines (5 min, 60 °C). Consistent with previous NMR studies of secondary amides, each of these were observed as a resolved mixture of the s-cis and s-trans rotamers [19]. Product 16

The use of isoxazoline and isoxazole scaffolding in the design of novel thiourea and amide liquid-crystalline compounds

• Itamar L. Gonçalves,
• Rafaela R. da Rosa,
• Vera L. Eifler-Lima and
• Aloir A. Merlo

Beilstein J. Org. Chem. 2020, 16, 175–184, doi:10.3762/bjoc.16.20

• in the reaction of thiourea with primary amines [6]. Another important synthetic route for substituted thioureas is a two-step approach: (i) the addition/elimination reaction of benzoyl chloride, with a thiocyanate salt, generating in situ, benzoyl isothiocyanate, and (ii) an appropriate amine

One-pot synthesis of substituted pyrrolo[3,4-b]pyridine-4,5-diones based on the reaction of N-(1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-oxo-2-arylethyl)acetamide with amines

• Valeriya G. Melekhina,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Vitaly S. Mityanov,
• Artem N. Fakhrutdinov,
• Arkady A. Dudinov,
• Vasily A. Migulin,
• Yulia V. Nelyubina,
• Elizaveta K. Melnikova and
• Michail M. Krayushkin

Beilstein J. Org. Chem. 2019, 15, 2840–2846, doi:10.3762/bjoc.15.277

• Federation Lomonosov Moscow State University, Moscow 119991, Russian Federation 10.3762/bjoc.15.277 Abstract The condensation of primary amines with N-(1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-oxo-2-arylethyl)acetamides was explored. Thus, a previously unknown recyclization of the starting material was

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• ) in the kinetic resolution of primary amines 60 via their electrocatalytic oxidation to the corresponding ketones 62, and remaining amines (R)-60 were obtained with very high enantioselectivity. The controlled potential electrolysis was carried out in a divided cell in the presence of a base and a

• supporting electrolyte. Asymmetric anodic oxidation of enol acetates using chiral supporting electrolytes. Kinetic resolution of primary amines using a chiral N-oxyl radical mediator

Synthesis and properties of sulfur-functionalized triarylmethylium, acridinium and triangulenium dyes

• Marco Santella,
• Eduardo Della Pia,
• Jakob Kryger Sørensen and
• Bo W. Laursen

Beilstein J. Org. Chem. 2019, 15, 2133–2141, doi:10.3762/bjoc.15.210

• ] lacking para-substituents and for the para-amino-substituted analogue [17] (step 2 in Figure 1). It was found that the reactivity in SNAr reactions of 1 with primary amines was high and the acridinium compounds 4a,b were obtained in few minutes after the addition of 2 equiv of the corresponding primary

• triarylmethylium ions via SNAr reactions was demonstrated. These new thioether-substituted triarylmethylium ions provide access to a broad range of new heterocyclic carbenium dyes of the xanthenium, acridinium and triangulenium type via further SNAr reactions with primary amines and ring-closure reactions. The

Synthesis and anion binding properties of phthalimide-containing corona[6]arenes

• Meng-Di Gu,
• Yao Lu and
• Mei-Xiang Wang

Beilstein J. Org. Chem. 2019, 15, 1976–1983, doi:10.3762/bjoc.15.193

• -substituted 3,6-dihydroxyphthalimide derivatives are accessible conveniently from the reaction between various commercially available functional primary amines and 3,6-dihydoxyphthalic anhydride. The ready availability of N-functionalized 3,6-dihydroxyphthalimides would therefore enable the construction of

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• alkynylpalladium complex 25 in the proposed pathway. Other benzoic acid derivatives such as those bearing a formyl substituent at the ortho position also take part in several multicomponent cyclizations leading to isoindolinones. Thus, 2-formylbenzoate 29, primary amines 2 and terminal alkynes 18 react under

• -component cyclization of 2-formylbenzoic acids, primary amines and a 1,3-dicarbonyl compounds. The first proposal uses 2-formylbenzoic acid 33 (R = H, conditions A, Scheme 9), cyclic aliphatic and aromatic diketones 34 such as dimedone (R2R3 = -CH2CMe2CH2-) as the 1,3-dicarbonyl partner and a variety of

A three-component, Zn(OTf)₂-mediated entry into trisubstituted 2-aminoimidazoles

• Alexei Lukin,
• Anna Bakholdina,
• Anna Kryukova,
• Alexander Sapegin and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2019, 15, 1061–1064, doi:10.3762/bjoc.15.103

• from the respective isocyanates and propargylamine (or propagyl isocyanate and primary amines), thus could offer an opportunity to synthesize 2-aminoimidazoles 5 in a three-component format. Considering these premises, we started to explore the Zn(OTf)2-catalyzed reaction of 4 with primary amines

• and the reaction of propargylureas 4 with primary amines studied in this work. Substrate scope for the three-component synthesis of 5. Plausible mechanism for the formation of 5. Catalyst screening results for the conversion of 4a to 5a. Supporting Information Supporting Information File 134: General

Diaminoterephthalate–α-lipoic acid conjugates with fluorinated residues

• Leon Buschbeck,
• Aleksandra Markovic,
• Gunther Wittstock and
• Jens Christoffers

Beilstein J. Org. Chem. 2019, 15, 981–991, doi:10.3762/bjoc.15.96

• primary amines [6][7], can be regarded as a molecular scaffold [8], which can be orthogonally equipped with different functional units [9] by simple transformations. Thus, different applications in materials science [10] and life sciences [11][12] can be addressed by tailored functional DATs. As an

Easy, efficient and versatile one-pot synthesis of Janus-type-substituted fullerenols

• Marius Kunkel and
• Sebastian Polarz

Beilstein J. Org. Chem. 2019, 15, 901–905, doi:10.3762/bjoc.15.87

• substituted fullerenol with five substituents on one pole of the fullerene and polyhydroxylation moieties, mostly ether and hydroxy groups, on the rest of the fullerene core. As substituents a broad variety of primary amines can be used to obtain Janus-type amphiphilic fullerenols in good to excellent yield

• synthetic pathways, which allow to introduce a broader variety of substituents and better yield. We report an easy and efficient one-pot approach using C60Cl6 as a precursor. The attachment of substituents, in our case primary amines, and the polyhydroxylation of the fullerene core are performed

• synthesized according to procedure reported by Kuvychko et al. and adapted by our group [27][28][29]. Though, several compounds are known to undergo the penta-substitution reaction with C60Cl6, like amines, thiols or alcohols [30][31][32], it has been observed that primary amines show a high reactivity under

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• [112]. In this work they have also demonstrated that metallic pnictogens do form sufficiently strong halogen bonds to enable co-crystal formation. Mal and co-workers have shown that a contact explosive, i.e., the mixture of primary amines and phenyliodine diacetate led to a high-yielding reaction at

• maximum contact (solvent-free ball milling) of the reactants [113]. An acid salt, (sodium bisulfate) was used to control the reactivity of the highly basic primary amines to transform the exceedingly exothermic reactive substrates in a high-yielding cross-dehydrogenative coupling (CDC) reaction to obtain

• (pyridin-4-yl)ethylene and 4,6-dichlororesorcinol. Halogen-bonded co-crystals via a) I···P, b) I···As, and c) I···Sb bonds [112]. Transformation of contact-explosive primary amines and iodine(III) into a successful chemical reaction for amide synthesis. Undirected C–H functionalization by using the acidic

Efficient synthesis of pyrazolopyridines containing a chromane backbone through domino reaction

• Razieh Navari,
• Saeed Balalaie,
• Saber Mehrparvar,
• Fatemeh Darvish,
• Frank Rominger,
• Fatima Hamdan and
• Sattar Mirzaie

Beilstein J. Org. Chem. 2019, 15, 874–880, doi:10.3762/bjoc.15.85

• base-catalyzed cyclization reaction is reported. The synthesis was carried out through a three-component reaction of (arylhydrazono)methyl-4H-chromen-4-one, malononitrile, primary amines in the presence of Et3N at room temperature. However, carrying out the reaction under the same conditions without

• construct fused heterocyclic skeletons [37][38][39][40], we describe the synthesis of pyrazolopyridines 4a–m containing a chromone moiety (Scheme 1). The synthetic approach was based on a domino reaction of (arylhydrazono)methyl-4H-chromen-4-one 1a–g, primary amines 2a–c, and malononitrile (3) in the

• reaction with different primary amines and malononitrile were examined and compounds 4a–m were formed. The results are summarized in Figure 3. In another experiment, the model reaction of (arylhydrazono)methyl-4H-chromen-4-one (1a), phenylethylamine (2b), and malononitrile (3) were investigated in ethanol

Synthesis of a novel category of pseudo-peptides using an Ugi three-component reaction of levulinic acid as bifunctional substrate, amines, and amino acid-based isocyanides

• Maryam Khalesi,
• Azim Ziyaei Halimehjani and
• Jürgen Martens

Beilstein J. Org. Chem. 2019, 15, 852–857, doi:10.3762/bjoc.15.82

• aliphatic amines and ordinary isocyanides with excellent yields [24]. In 2003, Mironov et al. reported the Ugi reaction of levulinic acid, isocyanides and primary amines in aqueous media with high yields [25]. In addition, Banfi et al. have shown that by using levulinic acid in multicomponent reactions and

Synthesis and SAR of the antistaphylococcal natural product nematophin from Xenorhabdus nematophila

• Frank Wesche,
• Hélène Adihou,
• Thomas A. Wichelhaus and
• Helge B. Bode

Beilstein J. Org. Chem. 2019, 15, 535–541, doi:10.3762/bjoc.15.47

• the desired primary amines in good yields (18, 19, 25, and 26) (Scheme 2 and Scheme 3). With all building blocks available, the synthesis of the appropriate fluorescent derivatives was performed as before, using (rac)-3-methyl-2-oxopentanoic acid. Yields after coupling and bioactivities are summarized

Microwave-assisted synthesis of N,N-bis(phosphinoylmethyl)amines and N,N,N-tris(phosphinoylmethyl)amines bearing different substituents on the phosphorus atoms

• Erika Bálint,
• Anna Tripolszky,
• László Hegedűs and
• György Keglevich

Beilstein J. Org. Chem. 2019, 15, 469–473, doi:10.3762/bjoc.15.40

• were also prepared by the double Kabachnik–Fields reaction using primary amines [11][14][15], amino acids [16][17] or aminoethanol [14] as the amine component. To the best of our knowledge, only one example can be found for a bis(α-aminophosphine oxide) containing different P-functions that was

• containing different substituents on the phosphorus atoms First, the (aminomethyl)phosphine oxide starting materials 5–7 were synthesized following our previous protocol [11]. Thus, the MW-assisted Kabachnik–Fields reaction of primary amines (butyl-, cyclohexyl- or benzylamine), paraformaldehyde and di(p

Adhesion, forces and the stability of interfaces

• Robin Guttmann,
• Johannes Hoja,
• Christoph Lechner,
• Reinhard J. Maurer and
• Alexander F. Sax

Beilstein J. Org. Chem. 2019, 15, 106–129, doi:10.3762/bjoc.15.12

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• explored for tetrasubstituted imidazole synthesis from primary amines, aromatic aldehydes, ammonium acetate, and phenylglyoxal. The TFE-modified SMSM had better behavior than others. To highlight the catalytic activity of the RFOH/SBA-15-Pr-SO3H, the reaction was also carried out with non-RFOH

• –270 °C for 20 h, (e) after filtration, washing, and drying, MWCNTs-SO3H composite 97 was achieved (Scheme 17). N-Substituted pyrroles 99 were obtained in good to excellent yields (40–92%) via a simple and green reaction between 2,5-dimethoxytetrahydrofuran (98) and primary amines 15 in water media at