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

• found to exhibit a broad range of biological activities [11][12][13]. 3-Formylchromone was used as a suitable starting material for the construction of various heterocyclic skeletons [14][15][16][17]. Pyrazolopyridines are a promising class of heterocyclic compounds which inhibits cyclin-dependent

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

• post-multicomponent reactions, diversities of bicyclic drug-like heterocyclic compounds can be obtained [26]. Results and Discussion In continuation of our interest on the synthesis of novel pseudo-peptides [27][28][29] via multicomponent reactions, herein we investigate the Ugi-4C-3CR of levulinic

Azologization of serotonin 5-HT₃ receptor antagonists

• Karin Rustler,
• Galyna Maleeva,
• Piotr Bregestovski and
• Burkhard König

Beilstein J. Org. Chem. 2019, 15, 780–788, doi:10.3762/bjoc.15.74

• thermal half-lives (THL) of the cis-isomers of compounds 5a, 5b, 12a, 16a–d, 23, and 28 was accomplished by monitoring the increase in absorbance which corresponds to the evolution of the trans-isomer after irradiation and exposure to dark. In contrast to the heterocyclic compounds 5a, 5b, 12a, and 16a–d

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• highly substituted heterocyclic compounds is possible. An intramolecular aldol-type condensation reaction efficiently furnishes pyridin-4-ols PY that can be further modified by palladium-catalyzed reactions, e.g., to specifically substituted furopyridine derivatives. Condensations of β-ketoenamides with

• particular heterocyclic compounds. The synthesis of pyrimidines PM, pyrimidine N-oxides PO, oxazoles OX, 1,2-diketones DK and quinoxalines QU starting from β-ketoenamides KE is the topic of the present review. Review Scope of the LANCA three-component synthesis of β-ketoenamides The scope of the LANCA three

• worth mentioning that the relatively complex heterocyclic compounds depicted in Scheme 10 are accessible through the three-component reaction and subsequent condensation reaction in only two steps. Functionalization of pyrimidine derivatives The substitution pattern of the prepared pyrimidine

Catalyst-free assembly of giant tris(heteroaryl)methanes: synthesis of novel pharmacophoric triads and model sterically crowded tris(heteroaryl/aryl)methyl cation salts

• Rodrigo Abonia,
• Luisa F. Gutiérrez,
• Braulio Insuasty,
• Jairo Quiroga,
• Kenneth K. Laali,
• Chunqing Zhao,
• Gabriela L. Borosky,
• Samantha M. Horwitz and
• Scott D. Bunge

Beilstein J. Org. Chem. 2019, 15, 642–654, doi:10.3762/bjoc.15.60

• Rodrigo Abonia Luisa F. Gutierrez Braulio Insuasty Jairo Quiroga Kenneth K. Laali Chunqing Zhao Gabriela L. Borosky Samantha M. Horwitz Scott D. Bunge Research Group of Heterocyclic Compounds (GICH), Department of Chemistry, Universidad del Valle, A. A. 25360, Cali, Colombia Department of

• the indole and coumarin partners also characterizes these approaches, Scheme 2. Continuing our current program on the synthesis of quinoline-based heterocyclic compounds of biological interest [54][55][56][57], we describe here a Yonemitsu-based direct and reproducible three-component synthesis of

Green synthesis of new chiral 1-(arylamino)imidazo[2,1-a]isoindole-2,5-diones from the corresponding α-amino acid arylhydrazides in aqueous medium

• Nadia Bouzayani,
• Jamil Kraїem,
• Sylvain Marque,
• Yakdhane Kacem,
• Abel Carlin-Sinclair,
• Jérôme Marrot and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2018, 14, 2923–2930, doi:10.3762/bjoc.14.271

• directed toward the development of environmentally safe conditions for the synthesis of heterocyclic compounds starting from natural (L)-α-amino acids [19][20][21][22][23] and the reactivity of α-amino acid phenylhydrazides [24][25], we now report a green and eco-friendly procedure for the synthesis of new

Transition metal-free oxidative and deoxygenative C–H/C–Li cross-couplings of 2H-imidazole 1-oxides with carboranyl lithium as an efficient synthetic approach to azaheterocyclic carboranes

• Lidia A. Smyshliaeva,
• Mikhail V. Varaksin,
• Pavel A. Slepukhin,
• Oleg N. Chupakhin and
• Valery N. Charushin

Beilstein J. Org. Chem. 2018, 14, 2618–2626, doi:10.3762/bjoc.14.240

• boron-enriched scaffold, is likely to be due to unique properties of these organoboron compounds and materials based on them. Results and Discussion 2H-Imidazole 1-oxides are known to be non-aromatic heterocyclic compounds, bearing the electrophilic center C(5)–H, which is active for interaction with

Synthesis of dihydroquinazolines from 2-aminobenzylamine: N³-aryl derivatives with electron-withdrawing groups

• Nadia Gruber,
• Jimena E. Díaz and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2018, 14, 2510–2519, doi:10.3762/bjoc.14.227

• generated by Lewis acid-promoted halide abstraction from imidoyl chlorides or by alkylation of nitriles. A nucleophilic attack on such species followed by cyclization provides access to a variety of heterocycles. Intramolecular reactions of in situ generated nitrilium ions leading to heterocyclic compounds

Practical tetrafluoroethylene fragment installation through a coupling reaction of (1,1,2,2-tetrafluorobut-3-en-1-yl)zinc bromide with various electrophiles

• Ken Tamamoto,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2018, 14, 2375–2383, doi:10.3762/bjoc.14.213

• ), demonstrating a promising pathway for constructing CF2CF2-containing heterocyclic compounds. We also demonstrated the multigram preparation of CF2CF2-containing arenes through the present cross-coupling reaction, as shown in Scheme 2. Thus, treatment of 1.38 g (5.00 mmol) of ethyl o-iodobenzoate (3j) with 10.1

Chiral bisoxazoline ligands designed to stabilize bimetallic complexes

• Deepankar Das,
• Rudrajit Mal,
• Nisha Mittal,
• Zhengbo Zhu,
• Thomas J. Emge and
• Daniel Seidel

Beilstein J. Org. Chem. 2018, 14, 2002–2011, doi:10.3762/bjoc.14.175

• Deepankar Das Rudrajit Mal Nisha Mittal Zhengbo Zhu Thomas J. Emge Daniel Seidel Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3⁺ + 2]-cycloaddition/rearrangement reactions

• Lin-bo Luan,
• Zi-jie Song,
• Zhi-ming Li and
• Quan-rui Wang

Beilstein J. Org. Chem. 2018, 14, 1826–1833, doi:10.3762/bjoc.14.155

• furnishing the tricyclic 1,2,4-triazole-fused 1,4-benzodiazepines. Keywords: 1,4-benzodiazepine (BDZ); cyclization; hydrazones; oxidation; rearrangement; Introduction Heterocyclic compounds comprising a 1,4-benzodiazepine (BDZ) ring have been a topic of continued interest as they exhibit a wide spectrum of

Host–guest complexes of conformationally flexible C-hexyl-2-bromoresorcinarene and aromatic N-oxides: solid-state, solution and computational studies

• Rakesh Puttreddy,
• Ngong Kodiah Beyeh,
• S. Maryamdokht Taimoory,
• Daniel Meister,
• John F. Trant and
• Kari Rissanen

Beilstein J. Org. Chem. 2018, 14, 1723–1733, doi:10.3762/bjoc.14.146

• that resorcinarenes are particularly suited hosts for both neutral and protonated N-heterocyclic compounds [19][20] and alkyl ammonium cations [21][22][23][24][25]. The resulting complexes have been extensively studied in both solid and solution state. The most common defined interactions involve

An air-stable bisboron complex: a practical bidentate Lewis acid catalyst

• Longcheng Hong,
• Sebastian Ahles,
• Andreas H. Heindl,
• Gastelle Tiétcha,
• Andrey Petrov,
• Zhenpin Lu,
• Christian Logemann and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2018, 14, 618–625, doi:10.3762/bjoc.14.48

• of cyclic frameworks, especially in the synthesis of natural products [1][2]. Aza-dienes have been utilized in IEDDA reactions for the construction of nitrogen-containing heterocyclic compounds [3][4][5][6][7][8]. Among them, 1,2-diazines are less used owing to their relative low reactivity as their

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• intermediate reacts with the nucleophile (dienophile) species in different reactions to form a wide range of heterocyclic compounds. Reactions with C=C dienophiles Reactions of o-QMs with different C=C dienophiles are listed in Table 3. Osyanin et al. reported the efficient reaction of quaternary ammonium salt

Synthesis of fluoro-functionalized diaryl-λ³-iodonium salts and their cytotoxicity against human lymphoma U937 cells

• Prajwalita Das,
• Etsuko Tokunaga,
• Hidehiko Akiyama,
• Hiroki Doi,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2018, 14, 364–372, doi:10.3762/bjoc.14.24

• could themselves be highly potential drug candidates. All of the reagents that we developed contain at least one fluorine atom in their structures, which may explain why they have potential biological activity [4][5][6][7][8][9]. In addition, examination of the successful records of heterocyclic

• compounds in the pharmaceutical history indicates that some of these reagents have a heterocyclic skeleton which makes them suitable as drug candidates [29][30][31][32]. Among these compounds, our group is interested in investigating the biological activity of hypervalent iodine-type reagents [33

One-pot preparation of 4-aryl-3-bromocoumarins from 4-aryl-2-propynoic acids with diaryliodonium salts, TBAB, and Na₂S₂O₈

• Teppei Sasaki,
• Katsuhiko Moriyama and
• Hideo Togo

Beilstein J. Org. Chem. 2018, 14, 345–353, doi:10.3762/bjoc.14.22

• transformed into 4-phenylcoumarin derivatives bearing C–H, C–S, C–N, and C–C bonds at 3-position. Keywords: 3-aryl-2-propynoic acid; bromo-cyclization; coumarin; diaryliodonium triflate; O-phenylation; Introduction Coumarin is a benzo-α-pyrone and one of the typical heterocyclic compounds. The importance of

• the preparation of heterocyclic compounds [43][44][45][46], we would like to report an efficient one-pot preparation of 4-aryl-3-bromocoumarins by treatment of 3-aryl-2-propynoic acids with diaryliodonium triflate in the presence of a base, followed by the reaction with tetrabutylammonium bromide

Continuous-flow retro-Diels–Alder reaction: an efficient method for the preparation of pyrimidinone derivatives

• Imane Nekkaa,
• Márta Palkó,
• István M. Mándity and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2018, 14, 318–324, doi:10.3762/bjoc.14.20

• ] syntheses of heterocyclic compounds. The rDA products can be gained, due to a thermal [4 + 2]-cycloreversion, by distillation under reduced pressure [29], boiling in solvent [30][31], and applying microwave irradiation [32][33][34][35] or flash vacuum pyrolysis [35][36]. rDA reactions under mild conditions

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• yield of 10–36% [41]. 2.2. Vinylphosphonium salts in the intramolecular Wittig reaction As was already mentioned, in 1964 Schweizer provided a general method for preparing carbo- and heterocyclic compounds 38 using vinylphosphonium salts [1][2]. The method consisted in the reaction of oxygen, nitrogen

• provided two final four- and five-membered reaction products 94 and 95, respectively (Scheme 56) [69]. Another example of the generation of heterocyclic compounds via the intramolecular Wittig reaction is the synthesis of quinoline derivatives 99 from triphenylphosphine, acetylenedicarboxylic acid esters

Regioselective decarboxylative addition of malonic acid and its mono(thio)esters to 4-trifluoromethylpyrimidin-2(1H)-ones

• Sergii V. Melnykov,
• Andrii S. Pataman,
• Yurii V. Dmytriv,
• Svitlana V. Shishkina,
• Mykhailo V. Vovk and
• Volodymyr A. Sukach

Beilstein J. Org. Chem. 2017, 13, 2617–2625, doi:10.3762/bjoc.13.259

• -containing heterocyclic compounds [24][25][26][27][28][29]. It should be noted that the presence of a strong electron-withdrawing trifluoromethyl group is responsible for the sufficient reactivity of the electrophilic ketimine function with various carbon nucleophiles in these reactions. Recently, the

A novel synthetic approach to hydroimidazo[1,5-b]pyridazines by the recyclization of itaconimides and HPLC–HRMS monitoring of the reaction pathway

• Dmitry Yu. Vandyshev,
• Khidmet S. Shikhaliev,
• Andrey Yu. Potapov,
• Michael Yu. Krysin,
• Fedor I. Zubkov and
• Lyudmila V. Sapronova

Beilstein J. Org. Chem. 2017, 13, 2561–2568, doi:10.3762/bjoc.13.252

• virtually any carbon atom of the heterocyclic system is achievable in addition to hydrogenated imidazo[1,5-b]pyridazines [34][35]. Itaconimides, in contrast to itaconic acid, its esters, monoamides or anhydride [36][37], scarcely have been studied in the synthesis of heterocyclic compounds. The presence of

¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution

• Sergey L. Deev,
• Alexander S. Paramonov,
• Tatyana S. Shestakova,
• Igor A. Khalymbadzha,
• Oleg N. Chupakhin,
• Julia O. Subbotina,
• Oleg S. Eltsov,
• Pavel A. Slepukhin,
• Vladimir L. Rusinov,
• Alexander S. Arseniev and
• Zakhar O. Shenkarev

Beilstein J. Org. Chem. 2017, 13, 2535–2548, doi:10.3762/bjoc.13.250

• membranes. The conjugation of adamantane with heterocyclic compounds also provides a method to modify the pharmacological profile and frequently leads to a new type of bioactivity. For example, N-adamantyl tetrazoles 1 and 2 (Figure 1A) demonstrate lower toxicity and, simultaneously, more potent activity

• the studies of N-alkylated heterocyclic compounds with a high abundance of nitrogen nuclei, where 13C chemical shifts and 1H-1H NOE data cannot provide reliable structural information. The incorporation of the 15N-labels also permitted the study of the mechanism of isomerization of N-adamantylated

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• unreactive under these conditions. Electron-rich aromatic heterocyclic compounds such as pyrroles and indoles enter reactions with nitrosoalkenes more smoothly [44][45][46][47][48][49][50][51][52][53][54][55]). The addition of nitrosoalkenes to pyrroles and indoles is a convenient and mild strategy for the

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• acid is readily achieved by adding 2 N NaOH/water solution to the silylated phosphonate [178]. This two-step sequence: 1. bromotrimethylsilane; 2. methanolysis or hydrolysis was used for the synthesis of numerus phosphonic acids including heterocyclic compounds that are too sensitive to be prepared by

Preparation of imidazo[1,2-a]-N-heterocyclic derivatives with gem-difluorinated side chains

• Layal Hariss,
• Kamal Bou Hadir,
• Mirvat El-Masri,
• Thierry Roisnel,
• René Grée and
• Ali Hachem

Beilstein J. Org. Chem. 2017, 13, 2115–2121, doi:10.3762/bjoc.13.208

• coupling reactions as well as nucleophilic substitutions have been performed successfully in order to increase the molecular diversity. Keywords: aerobic oxidative coupling; imidazo[1,2-a]-N-heterocycles; gem-difluoroalkyl derivatives; propargylic fluorides; Introduction Nitrogen-containing heterocyclic

• compounds are frequently found in bioactive naturally occurring compounds, as well as in the synthetic pharmacopeia. Imidazo[1,2-a]pyridine is an important heterocyclic system present in many molecules featuring diverse biological activities, such as antiviral, antimicrobial, antitumor, anti-inflammatory

Metal-free hydroarylation of the side chain carbon–carbon double bond of 5-(2-arylethenyl)-3-aryl-1,2,4-oxadiazoles in triflic acid

• Anna S. Zalivatskaya,
• Dmitry S. Ryabukhin,
• Marina V. Tarasenko,
• Alexander Yu. Ivanov,
• Irina A. Boyarskaya,
• Elena V. Grinenko,
• Ludmila V. Osetrova,
• Eugeniy R. Kofanov and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2017, 13, 883–894, doi:10.3762/bjoc.13.89

• , N4,C-diprotonated forms of oxadiazoles are the electrophilic intermediates in this reaction. Keywords: Friedel–Crafts reaction; hydroarylation; oxadiazoles; superelectrophilic activation; triflic acid; Introduction Oxadiazoles are an important class of heterocyclic compounds and great attention has