Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Katarzyna Urbaniak,
• Marcin Jasiński,
• Vladyslav Bakhonsky,
• Peter R. Schreiner and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2019, 15, 497–505, doi:10.3762/bjoc.15.43

• temperature [14]. An important reaction of 1 is the O-alkylation leading to alkoxyimidazolium salts, which display in some cases properties of ‘room temperature ionic liquids’ [15][16]. Finally, straightforward deoxygenation by treatment with Raney-Ni is also worth mentioning [17]. Condensations presented in

• -tetramethylcyclobutane-1,3-dione. Imidazolium salts are of special importance as they are widely used as ionic liquids or precursors of imidazole-based nucleophilic carbenes (imidazol-2-ylidenes). For example, deprotonation of 1,3-diadamantylimidazolium chloride led to the first stable imidazol-2-ylidene (the so-called

A chemoenzymatic synthesis of ceramide trafficking inhibitor HPA-12

• Seema V. Kanojia,
• Sucheta Chatterjee,
• Subrata Chattopadhyay and
• Dibakar Goswami

Beilstein J. Org. Chem. 2019, 15, 490–496, doi:10.3762/bjoc.15.42

• least three times without any significant loss of enzyme activity. There are similar instances in literature [48] for a substantial slow-down of the transesterification reaction rate in organic solvents. This issue can be overcome by using room temperature ionic liquids, which not only substitute the

• environment damaging organic solvent, but also increase the reaction rate, and provide many other technological advantages [49]. Towards this, we have chosen [bmim][BF4] and [bmim][PF6] as two model ionic liquids. Of them, [bmim][BF4] is water soluble, and [bmim][PF6] is immiscible with water. The acetylation

LCST phase behavior of benzo-21-crown-7 with different alkyl chains

• Yan Deng,
• Xing Li,
• Qiao Zhang,
• Zheng Luo,
• Chengyou Han and
• Shengyi Dong

Beilstein J. Org. Chem. 2019, 15, 437–444, doi:10.3762/bjoc.15.38

• molecules-containing systems has been developed exhibiting LCST behavior and adjustable thermo-responsive properties. These include ionic liquids [27][28][29][30], macrocycles [31][32][33][34], and supramolecular pairs [26][35][36][37][38]. For example, the combination of macrocycles and supramolecular

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

• handling, and even reusability [34]. Ionic liquids (ILs) have been extensively reported as green solvents in organic transformations, owing to their considerable properties such as the ability to dissolve a wide range of substances, very low vapor pressure, high thermal stability, recyclability, non

• -flammability, low volatility, and safety. These eco-friendly materials have been applied as a new category of catalysts in some organic reactions as well. Recently, new sulfonated ionic liquids and sulfonated solid salts have been prepared and used as efficient catalysts in various chemical reactions [35][36

• liquids 18 or 19 were again applied for next runs. Shirini et al. have reported a series of procedures for the synthesis of sulfonated materials and their applications for one-pot multicomponent reactions. This research group has reported a new route for the preparation of bi-SO3H ionic liquids based on

Learning from B₁₂ enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

• Keishiro Tahara,
• Ling Pan,
• Toshikazu Ono and
• Yoshio Hisaeda

Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232

• ) through dechlorination (Scheme 8b) [109]. A turnover number of 82 based on 1 was achieved. Mechanistic investigation revealed that the electrochemically generated Co(I) species of 1 participated in the dechlorination. To recycle the catalyst, ionic liquids are promising solvents due to their excellent

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

• more recent method starts from an aromatic amine and formaldehyde in the presence of ionic liquids and a controlled amount of 1-methyl-3-(2-(sulfoxy)ethyl)-1H-imidazol-3-ium chloride as the catalyst. The reaction affords the corresponding 1,4-dihydroquinzolin-3-ium tetrafluoroborates, which upon

• catalytic reductive conditions [61]. In conclusion, the already described methods for the synthesis of 4-unsustituted N-aryl-3,4-DHQs are either limited to symmetrical substitution patterns, lead to byproducts and afford low yields, require the use of complex catalysts and ionic liquids or involve reductive

Bi-mediated allylation of aldehydes in [bmim][Br]: a mechanistic investigation

• Mrunesh Koli,
• Sucheta Chatterjee,
• Subrata Chattopadhyay and
• Dibakar Goswami

Beilstein J. Org. Chem. 2018, 14, 2198–2203, doi:10.3762/bjoc.14.193

• solvent systems and room temperature ionic liquids (RTILs) is also ideal for probing in situ formation of different allylmetal species in solution, their stability and reactivity towards electrophiles [8][9][10]. Despite extensive investigation, several key factors of the reaction have not been adequately

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• epoxides using ionic liquids under solvent free conditions [27]. The reaction is compatible with the presence of alkyl halides (R1 = CH2Cl), alkyls (R1 = CH3), aryloxy (R1 = ArO) and aryls on the epoxide ring as well as a wide range of thiophenols bearing a variety of substituents (Scheme 8). The nature of

• oxidation to β-hydroxy sulfoxides under microwave irradiation. Gallium triflate-catalyzed ring opening of epoxides and one-pot oxidation. Thiolysis of epoxides and one-pot oxidation to β-hydroxy sulfoxides using Ga(OTf)3 as a catalyst. Ring opening of epoxide using ionic liquids under solvent-free

Mechanochemistry of nucleosides, nucleotides and related materials

• Olga Eguaogie,
• Joseph S. Vyle,
• Patrick F. Conlon,
• Manuela A. Gîlea and
• Yipei Liang

Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81

• solid nucleoside or nucleotide substrates have been performed in the presence of liquids. These may originate either from the use of reagents which are liquids or low-melting solids (which liquify upon grinding) or from the addition of stoichiometric quantities of molecular solvents (or ionic liquids

• POCl3 (e.g., Scheme 10), monoalkyl phosphorodichloridates or dialkyl phosphoromonochloridates in the absence of solvent has been reported [48]. Migaud and co-workers prepared highly water-sensitive phosphitylating agents directly from PCl3 in low viscosity ionic liquids derived from the tris

• solubility of substrates in the ionic liquids (<10 mM) which rendered the phosphitylating agents prone to hydrolysis. Highly reactive phosphoramidite derivatives of low molecular weight amines could be isolated by this route (on 40–60 mg scales). Under the same conditions, coupling of bis(2-cyanoethyl

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

• reactions is definitely more advantageous. Ionic liquids have also attracted considerable attention due to their „green chemistry” values, including reusability, high thermal stability and non-inflammability. Hajipour et al. reported the one-pot synthesis of 1-amidoalkyl-2-naphthols catalysed by N-(4

• -sulfobutyl)triethylammonium hydrogen sulfate ([TEBSA][HSO4]) as Brønsted acidic ionic liquid [24]. In addition, ethylammonium nitrate (EAN) [25], a sulfonic acid-functionalized benzimidazolium-based supported ionic liquid catalyst (SILC) [26], and carboxyl-functionalized benzimidazolium-based ionic liquids

• (CFBILs) [27] proved to be efficient in the reaction (Table 1, entries 8–10). Safari et al. combined the benefits of using magnetic nanoparticles and ionic liquids by the application of magnetic Fe3O4 nanoparticles functionalized with 1-methyl-3-(3-trimethoxysilylpropyl)-1H-imidazol-3-ium acetate (MNP-IL

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• , dehydration and aromatization reactions. The use of ionic liquids (non-volatile solvents) over toxic organic solvents makes it an environmentally benign process [45][46]. The synthesis of isomeric tetracyclic pyrazolo[3,4-b]pyridine-based coumarin chromophores 27 and 28 was reported by Chen et al. [47

• -aminopyrazole 16 and aldehydes 47 in various organic solvents and ionic liquids to synthesize pyrazolo[3,4-b]pyridine derivative 87 (Scheme 23). Ionic liquids provided high yields of 87 in very short time with the best results obtained in [bmim]Br whereas organic solvents resulted in low yields and took longer

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides

• Irwan Iskandar Roslan,
• Kian-Hong Ng,
• Gaik-Khuan Chuah and
• Stephan Jaenicke

Beilstein J. Org. Chem. 2017, 13, 2739–2750, doi:10.3762/bjoc.13.270

• -Diels–Alder reaction [87]. Coupling between alkynoic acid and 2-aminobenzothiazole and the use of ionic liquids have also been developed [88]. Heterogeneous catalysts such as kaolin and hydrotalcites have been employed in the synthesis of benzo[4,5]thiazolo[3,2-a]pyrimidin-4-ones [89][90

Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2698–2709, doi:10.3762/bjoc.13.268

• [31][32], for instance as chiral selectors or as catalysts in micro-heterogeneous or organized systems (micelles, Langmuir–Blodgett films, ionic liquids etc.). Finally, our study shows how the use of polarimetry, which has already been shown a powerful tool for the systematic study of the binding

Synthesis, effect of substituents on the regiochemistry and equilibrium studies of tetrazolo[1,5-a]pyrimidine/2-azidopyrimidines

• Elisandra Scapin,
• Paulo R. S. Salbego,
• Caroline R. Bender,
• Alexandre R. Meyer,
• Anderson B. Pagliari,
• Tainára Orlando,
• Geórgia C. Zimmer,
• Clarissa P. Frizzo,
• Helio G. Bonacorso,
• Nilo Zanatta and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 2396–2407, doi:10.3762/bjoc.13.237

• , using ionic liquids and water as solvents, and short reaction times. In addition, 5-substituted isomers have proved to be excellent models in carrying out a thorough investigation of the azide–tetrazole equilibrium mechanism by density functional theory (DFT) and various experimental methods (e.g., NMR

• conditions for the preparation of tetrazolo[1,5-a]pyrimidines, the reaction of β-enaminone 1a with 5-aminotetrazole (2) was carried out under several conditions using conventional solvents and ionic liquids (ILs) to provide 5-phenyltetrazolo[1,5-a]pyrimidine (3a). Two conditions in which the product exceeded

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• variations are adopted to improve the efficiency of this reaction for practical application towards drug discovery [126][127][128]. Modifications have been done in substrates by replacing urea with substituted ureas and thio urea, use of various 1,3-dicarbonyl compounds etc. Reactions using ionic liquids as

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

• Sadaf Hanif,
• Bernd Oschmann,
• Dmitri Spetter,
• Muhammad Nawaz Tahir,
• Wolfgang Tremel and
• Rudolf Zentel

Beilstein J. Org. Chem. 2017, 13, 1693–1701, doi:10.3762/bjoc.13.163

• ; ionic liquid; polymeric ionic liquid; RAFT polymerization; Introduction Ionic liquids (ILs) are organic salts. Most of them have a melting point below 100 °C [1][2]. These organic salts do not have the same structure like inorganic salts. This is due to the structure of the ion pairs. They are built of

• ]. Properties, like solubility can be varied easily by exchanging the anion. Ionic liquids are often used as an electrolyte or organic solvent. Furthermore, they are also used in catalysis or in organic synthesis. Due to their selective solubility for ions [6][7][8], they can be used to predetermine the

• presence of ions on surfaces, a property which is very important for electrochemical conversions or the uptake of ions into the crystal lattice [9]. Polymeric ionic liquids (PILs) are made of ionic liquids with a polymerizable group, like a vinyl or acrylate group. They build a new class of macromolecules

Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

• Desirée Leistenschneider,
• Nicolas Jäckel,
• Felix Hippauf,
• Volker Presser and
• Lars Borchardt

Beilstein J. Org. Chem. 2017, 13, 1332–1341, doi:10.3762/bjoc.13.130

• done in 1 M TEA-BF4 in acetonitrile (ACN) and neat EMIM-BF4 as an ionic liquid. Since ionic liquids show a lower ion mobility as compared to aqueous or organic electrolytes, a well-connected transport pore system is of particular importance to guarantee a fast ion transport and should result in better

• comparable to other known Kroll carbons [52] and non-doped mesoporous carbons [57]. At a high sweep rate of 500 mV s−1, the shape of the CV, recorded in the organic electrolyte (Figure 7A) remains nearly rectangular, which indicated a high power handling ability. The ion mobility of ionic liquids is lower

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• -arylpropanoic and 4-arylbutanoic acids has been reported in 2015 by Le et al. [22]. The authors applied a microwave-assisted intramolecular Friedel–Crafts acylation catalyzed by metal triflate in triflate-anion containing ionic liquids. This synthesis proceeded with the goals of green chemistry and allowed to

Extrusion – back to the future: Using an established technique to reform automated chemical synthesis

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 65–75, doi:10.3762/bjoc.13.9

• final milling process step typically employed in the conventional synthesis to increase the surface area was removed. Deep eutectic solvents Deep eutectic solvents (DESs) – regarded as a new generation of ionic liquids – are two-component ionic solvents with melting points lower than either constituent

β-Amino functionalization of cinnamic Weinreb amides in ionic liquid

• Yi-Ning Wang,
• Guo-Xiang Sun and
• Gang Qi

Beilstein J. Org. Chem. 2016, 12, 2372–2377, doi:10.3762/bjoc.12.231

• -protecting groups is relatively easier than those shown above; and 3) the ionic liquids are environmentally friendly and can be readily recycled. Results and Discussion The first attempt was to conduct the aminochlorination reaction of N-methoxy-N-methylcinnamoylamide (5a) in acetonitrile by using 2-NsNCl2

• as the nitrogen source and Cu(I)OTf as the metal catalyst [33][34]. However, there no aminochlorination products were observed. Next, we turned our attention to the use of ionic liquids, which have shown many significant advantages in the reported aminochlorination reactions [35][36][37]. However

Isosorbide and dimethyl carbonate: a green match

• Fabio Aricò and
• Pietro Tundo

Beilstein J. Org. Chem. 2016, 12, 2256–2266, doi:10.3762/bjoc.12.218

• glucose by hydrolysis. Hydrogenation of glucose to D-sorbitol. An appropriate catalyst for this process should provide both acid sites (hydrolysis) and metallic sites (hydrogenation). Thus, several bifunctional catalytic systems have been investigated [40][41][42][43][44]. The use of ionic liquids as

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

• Maurizio Selva,
• Alvise Perosa,
• Sandro Guidi and
• Lisa Cattelan

Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181

• Maurizio Selva Alvise Perosa Sandro Guidi Lisa Cattelan Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, Via Torino, 155 – Venezia Mestre, Italy 10.3762/bjoc.12.181 Abstract The use of ionic liquids (ILs) as organocatalysts is reviewed for transesterification

• reactions, specifically for the conversion of nontoxic compounds such as dialkyl carbonates to both linear mono-transesterification products or alkylene carbonates. An introductory survey compares pros and cons of classic catalysts based on both acidic and basic systems, to ionic liquids. Then, innovative

• /nucleophilic) activation of reactants. Keywords: ionic liquids; transesterification; organocatalysts; organic carbonates; Review Introduction Transesterification catalysts The transesterification is one of the classical organic reactions that has found numerous applications in laboratory practice as well as

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• studies on this topic [196][239][240][241][242][243][244][245][246]. Hydroxylated and methoxylated benzaldehydes 69 (Scheme 21) and acetophenones 72 (Scheme 22) can be oxidized to the corresponding phenols 70a–d, and 73 in good yields in the presence of the H2O2/MeReO3 system in ionic liquids [bmim]BF4 or

Microwave-assisted synthesis of (aminomethylene)bisphosphine oxides and (aminomethylene)bisphosphonates by a three-component condensation

• Erika Bálint,
• Ádám Tajti,
• Anna Dzielak,
• Gerhard Hägele and
• György Keglevich

Beilstein J. Org. Chem. 2016, 12, 1493–1502, doi:10.3762/bjoc.12.146

• [15][16][17][18][19][20][21]. The use of crown ethers with an NH unit, or thienopyrimidine amines as starting materials was also reported [22][23]. The catalyst- and solvent-free methods required long reaction times and/or a high temperature [6][7][8][9][10][11][12][13][14][21][22][23]. Ionic liquids

Mutagenic activity of quaternary ammonium salt derivatives of carbohydrates

• Barbara Dmochowska,
• Karol Sikora,
• Anna Woziwodzka,
• Jacek Piosik and
• Beata Podgórska

Beilstein J. Org. Chem. 2016, 12, 1434–1439, doi:10.3762/bjoc.12.138

• construction [7][8][9]. Moreover, QASs are applied in industry, agriculture (as pesticides and herbicides) [10], and chemistry (as catalysts and solvents) [11][12]. QASs are also used as ingredients in hair conditioners, shampoos, and toothpastes [13]. Ionic liquids (IL) are recognized as a particularly