Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

• necessary to eliminate a high amount of internal carbon for the formation of a well-developed and highly porous carbon structure [6]. In general, the physical activation of carbon materials has the advantage over chemical activation to avoid impurities or additives in the final materials from the

Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties

• Liliia Moshniaha,
• Marika Żyła-Karwowska,
• Joanna Cybińska,
• Piotr J. Chmielewski,
• Ludovic Favereau and
• Marcin Stępień

Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81

• and increasing curvature of the bipyrrole linkage. The efficiency of the oxygenation step is dependent on a several of factors, i.e., Pd loading, concentration, and additives. The isolation of unoxygenated products cNMI2H and cNMI3H emphasizes the role of acceptor units and decreased inter-pyrrole

Synthesis of new asparagine-based glycopeptides for future scanning tunneling microscopy investigations

• Laura Sršan and
• Thomas Ziegler

Beilstein J. Org. Chem. 2020, 16, 888–894, doi:10.3762/bjoc.16.80

• coupling reagents, such as benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (BOP) or diisopropyl carbodiimide (DIC) and additives, such as 1-hydroxybenzotriazole (HOBt) or triethylphosphine. [29][30][31] However, in our hands, none of the described methods reached the high yields that

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• state quencher, as well as by the lowered rate of the reaction in the presence of the triplet energy quencher 2,5-dimethylhexa-2,4-diene or pyridazines, additives with lower triplet state energies than 4-anisaldehyde (52). The fact that the solvent polarity did not affect the sensitivity of the process

Efficient synthesis of piperazinyl amides of 18β-glycyrrhetinic acid

• Dong Cai,
• ZhiHua Zhang,
• Yufan Meng,
• KaiLi Zhu,
• LiYi Chen,
• ChangXiang Yu,
• ChangWei Yu,
• ZiYi Fu,
• DianShen Yang and
• YiXia Gong

Beilstein J. Org. Chem. 2020, 16, 798–808, doi:10.3762/bjoc.16.73

• with 1-Boc-piperazine (2.5 equiv) without any other additives can readily proceed in acetonitrile at reflux temperature in 95% yield. Having demonstrated the effectiveness of the new procedure, we decided to apply this method towards the synthesis of compound 10. But our investigations proved that the

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• as gold catalysts (e.g., gold(I) cyanide), solvents (e.g., CH2Cl2, THF, MeCN, DMF), additives (e.g., TFA, Sc(OTf)3), and temperature, the reaction conditions as mentioned earlier were chosen for the synthesis of 5a and 6a (Table S1, Supporting Information File 1). Because of the electron-deficient

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

Aerobic synthesis of N-sulfonylamidines mediated by N-heterocyclic carbene copper(I) catalysts

• Faïma Lazreg,
• Marie Vasseur,
• Alexandra M. Z. Slawin and
• Catherine S. J. Cazin

Beilstein J. Org. Chem. 2020, 16, 482–491, doi:10.3762/bjoc.16.43

• between alkyne, sulfonyl azide and amine/alcohol was described as a synthetic route to generate sulfonyltriazole intermediates. However, the presence of additives and high catalyst loading (CuI 10 mol %) were required for the synthesis of N-sulfonylimidates (Scheme 1, left). Over the last two decades

Synthesis of 4-amino-5-fluoropyrimidines and 5-amino-4-fluoropyrazoles from a β-fluoroenolate salt

• Tobias Lucas,
• Jule-Philipp Dietz and
• Till Opatz

Beilstein J. Org. Chem. 2020, 16, 445–450, doi:10.3762/bjoc.16.41

• . The hydrochlorides furnished the highest yields and no undesired byproducts were formed. In contrast to the related reaction with guanidinium salts [36], the reactions with amidine hydrochlorides did not require any basic additives. Under these improved conditions, the scope of the reaction for

Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds

• Vuyisa Mzozoyana,
• Fanie R. van Heerden and
• Craig Grimmer

Beilstein J. Org. Chem. 2020, 16, 190–199, doi:10.3762/bjoc.16.22

• coumarins have been identified from natural sources [1][2]. Coumarins have been reported to play a vital role as food and cosmetics constituents, cigarette additives, and dye-sensitized solar cells [3][4]. In addition, coumarins possess some biological activities such as anti-inflammatory [5], antitumor [6

Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst

• Abhijit Paul,
• Debnath Chatterjee,
• Srirupa Banerjee and
• Somnath Yadav

Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16

• observed. To further test the functional group tolerance of the reaction, we employed a modified version of the “robustness screen” method promulgated by Glorius and co-workers [50][51][52]. For this purpose, the reaction of indole (1a) was carried out with 2b in the presence of several additives bearing

Synthetic terpenoids in the world of fragrances: Iso E Super^® is the showcase

• Alexey Stepanyuk and
• Andreas Kirschning

Beilstein J. Org. Chem. 2019, 15, 2590–2602, doi:10.3762/bjoc.15.252

• . described a process, which involves methanol and other alcohols or alternatively organic acids as nucleophilic additives that can reversibly be introduced and removed again (Scheme 8). Typically, methanol, ethanol, isopropanol and 2-methoxyethanol served as suitable alcohols. According to patent information

• di- or polyols can also serve as “dummy” additives. Alternatively, also acetic acid was suggested. Using this method, the desired Iso E Super Plus® (34) concentration ranged from 5% to 7% as judged by GC analysis [26]. Fráter and Schröder discovered that Iso E Super Plus® (34) can undergo an

• formation of products. Most importantly, Iso E Super® (33), Iso E Super Plus® (34) and Iso Gamma (55) are formed [1]. All compounds are obtained as racemates [25]. Isomerisation using additives such as alcohols or carboxylic acids. The product with the γ-positioned double bond is the desired Iso E Super

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• radical, leading to the desired C–F bond formation. The excellent selectivity of the desired fluorinated product was obtained without additives. In addition, a catalytic amount of iron(III) complex [FeCl4][FeCl2(dmf)3] was found to improve the yields in some cases (Scheme 43). With an Fe(II)-catalyzed

• reaction proceeded efficiently for a wide range of alkyl and aryl-substituted α,β-unsaturated carboxylic acids derivatives with excellent E/Z selectivity (Scheme 76). It's worth mentioning that the addition of Ag2CO3 additives was crucial for promoting the decarboxylation of α,β-unsaturated carboxylic

Synthesis of benzo[d]imidazo[2,1-b]benzoselenoazoles: Cs₂CO₃-mediated cyclization of 1-(2-bromoaryl)benzimidazoles with selenium

• Mio Matsumura,
• Yuki Kitamura,
• Arisa Yamauchi,
• Yoshitaka Kanazawa,
• Yuki Murata,
• Tadashi Hyodo,
• Kentaro Yamaguchi and
• Shuji Yasuike

Beilstein J. Org. Chem. 2019, 15, 2029–2035, doi:10.3762/bjoc.15.199

• conditions for the cyclization of a chalcogen with 1-(2-bromophenyl)benzimidazole (1a). Table 1 shows the results from the screening of additives, solvents, and chalcogens. Since most of these types of reactions require a transition metal catalyst such as a copper reagent [14][15][16], the reaction between

Morphology-tunable and pH-responsive supramolecular self-assemblies based on AB₂-type host–guest-conjugated amphiphilic molecules for controlled drug delivery

• Yang Bai,
• Cai-ping Liu,
• Di Chen,
• Long-hai Zhuo,
• Huai-tian Bu and
• Wei Tian

Beilstein J. Org. Chem. 2019, 15, 1925–1932, doi:10.3762/bjoc.15.188

• Yang Bai Cai-ping Liu Di Chen Long-hai Zhuo Huai-tian Bu Wei Tian Shaanxi Key Laboratory of Chemical Additives for Industry, College of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China MOE Key Laboratory of Material Physics and Chemistry under

A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage

• Kesari Lakshmi Manasa,
• Yellaiah Tangella,
• Namballa Hari Krishna and
• Mallika Alvala

Beilstein J. Org. Chem. 2019, 15, 1864–1871, doi:10.3762/bjoc.15.182

• new C–N bonds in the presence of transition metal catalysts [25][26][27][28][29][30][31][32][33][34]. Tang and Jiao reported copper catalyzed C–C single bond cleavage and C–N bond formation [35]. However, the transition metal catalysts and additives employed in these transformations are toxic and

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• 0.15 eV (neglecting entropy changes during the light absorption) is required to efficiently inject photo excited electrons from the LUMO of the dyes in the CB of the oxide [34]. Usually iodine-based liquid electrolytes are comprising additives such as tert-butylpyridine (tBP) which is known to shift

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• preservance of the sensitive aldehyde group in the product structure, which can act as a precursor for the synthesis of some new motifs (Scheme 29) [117]. The reaction was carried out between 2-APs 3 and cinnamaldehyde derivatives 88 under aerobic conditions. ZnCl2 and pyridine act as additives, where ZnCl2

Mechanochemical Friedel–Crafts acylations

• Mateja Đud,
• Anamarija Briš,
• Iva Jušinski,
• Davor Gracin and
• Davor Margetić

Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130

• grinding additives to improve mass transfer and prevent pasting of the reaction mixture [26][27][28] (Table 1, entries 5–8) was detrimental to reaction yields. The addition of a small amount of solvents which was reported to facilitate several ball milling reactions (liquid assisted grinding, LAG) [29][30

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

• by acid catalysis from renewable resources, such as sugars, lignocellulosic biomass and waste materials [18]. It can be used as a bifunctional precursor for the synthesis of pharmaceuticals, plasticizers, and different additives [19]. Furthermore, it is recognized as an excellent starting material

An improved synthesis of adefovir and related analogues

• David J. Jones,
• Eileen M. O’Leary and
• Timothy P. O’Sullivan

Beilstein J. Org. Chem. 2019, 15, 801–810, doi:10.3762/bjoc.15.77

• significantly lower conversion to 6 than when tosylate 5 was employed. Optimisation of other aspects of this reaction (e.g., choice of base, solvent, temperature and the role of additives) has already been investigated by Brown Ripin [37][40] and Riley [38] which suggested that further investigation had limited

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

• State University, Kent, OH 44242, USA 10.3762/bjoc.15.60 Abstract A series of giant tris(heteroaryl)methanes are easily assembled by one-pot three-component synthesis by simple reflux in ethanol without catalyst or additives. Diversely substituted indoles (Ar1) react with quinoline aldehydes, quinolone

Ammonium-tagged ruthenium-based catalysts for olefin metathesis in aqueous media under ultrasound and microwave irradiation

• Łukasz Gułajski,
• Andrzej Tracz,
• Katarzyna Urbaniak,
• Stefan J. Czarnocki,
• Michał Bieniek and
• Tomasz K. Olszewski

Beilstein J. Org. Chem. 2019, 15, 160–166, doi:10.3762/bjoc.15.16

• in water including the development of specially designed water-soluble catalysts [21][22][23][24][25][26][27][28], addition of organic solvents [29][30][31], or use of additives such as for example calixarenes or cyclodextrins [32][33], chloride salts [34], vitamin E-based amphiphiles [35

• structure of the tailored catalysts and thus difficulties associated with their synthesis, or the need to use additives or co-solvents to improve the solubility of reacting species, still remain. Therefore, further development of catalytic systems would provide a complimentary extension to the scope of this

Gold-catalyzed ethylene cyclopropanation

• Silvia G. Rull,
• Andrea Olmos and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2019, 15, 67–71, doi:10.3762/bjoc.15.7

• additives [11], alkylating reagent in the Friedel–Crafts synthesis of indanones [12] or as synthon toward the introduction of cyclopropyl moieties in compounds with medicinal or biological interest [13][14]. In view of the lack of examples of direct conversions of ethylene into cyclopropanecarboxylates, and

N-Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes

• Fabienne Speck,
• David Rombach and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 52–59, doi:10.3762/bjoc.15.5

• only in stationary low concentrations. In the past, we used electron mediators as additives (triethylamine) [19][26] or peptides with substrate-binding sites [31][32] to overcome this problem. For the current work, we propose a radical ion pair in a solvent cage that undergoes an extremely fast proton