Synthetic mRNA capping

• Fabian Muttach,
• Nils Muthmann and
• Andrea Rentmeister

Beilstein J. Org. Chem. 2017, 13, 2819–2832, doi:10.3762/bjoc.13.274

• , comprising phenylthio [56], 5-chloro-8-quinolyl [57], morpholidate [48] and imidazolide moieties [58][59]. Imidazole activation in DMF with ZnCl2 was first reported by Sekine et al. [60] and is the most often used method for the formation of triphosphates. P-Imidazoles are known to react with numerous

• hydrolytically less stable than other purine nucleosides. Under basic conditions which are commonly used for RNA deprotection and cleavage from the solid support, opening of the imidazole ring of the 7-methylguanine would occur [111]. Thus, for synthesis of the cap structure on the solid support, standard

• trypanosomatid cap4 structure, characterized by 2′-O-methylation of the first four nucleotides and additional methylation at the first adenosine and the fourth uridine, was reported in 2004 by the group of Darzynkiewicz. The preparation was achieved by reacting an imidazole activated m7GDP with the 5

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

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

• -addition by the activated C=C double bond and subsequent intramolecular recyclization of the intermediate with the amino group involved. Keywords: cascade reaction; diaminoimidazoles; HPLC–HRESIMS; imidazo[1,5-b]pyridazines; itaconimides; Introduction Among the numerous bicyclic fused imidazole

• ], antitumor agents [9], and are stimulators of guanylate cyclase [10], whereas imidazo[1,5-c]pyrimidines demonstrate anti-infectious effects in the treatment of brucellosis [11], etc. However, the chemistry, medicinal chemistry and pharmacology of imidazo[1,5-b]pyridazines, with the imidazole ring connected

• to search for new reagents for the synthesis of their imidazo[1,5-b]-annelated analogues. There are two general approaches to the construction of an imidazo[1,5-b]pyridazine scaffold: the annulation of the imidazole ring to the b-bond of the pyridazine (route A, Scheme 1) and the heterocyclization 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

• against influenza A virus compared with the currently used antiviral drug rimantadine (1-(1-adamantyl)ethanamine) [3]. More recently, Roberge et al. described new inhibitors of the influenza A virus M2 proton channel. Among the studied compounds, adamantyl imidazole 3 showed good activity [4]. An azolo

Exploring mechanochemistry to turn organic bio-relevant molecules into metal-organic frameworks: a short review

• Vânia André,
• Sílvia Quaresma,
• João Luís Ferreira da Silva and
• M. Teresa Duarte

Beilstein J. Org. Chem. 2017, 13, 2416–2427, doi:10.3762/bjoc.13.239

• framework and have simultaneously the characteristics of MOFs and zeolites, making them very promising for biomedical applications [90][91]. In their work, Beldon et al. explored the synthesis of new ZIFs using imidazole (HIm), 2-methylimidazole (HMeIm) and 2-ethylimidazole (HEtIm) as ligands. Initially

• , they used LAG with ZnO and the previous imidazole ligands in the presence of DMF as a space-filling liquid. However, this method only partially succeeded: with HIm the quantitative formation of ZIF-4 was obtained after 60 min, whereas with HMeIm only partial formation of ZIF-8 was achieved and with

The effect of milling frequency on a mechanochemical organic reaction monitored by in situ Raman spectroscopy

• Patrick A. Julien,
• Ivani Malvestiti and
• Tomislav Friščić

Beilstein J. Org. Chem. 2017, 13, 2160–2168, doi:10.3762/bjoc.13.216

• mechanochemical synthesis of a MOF from ZnO and imidazole in the presence of a small amount of N,N-dimethylformamide [41]. This study revealed reaction kinetics consistent with a 2nd order reaction rate law, rationalized through a “pseudo-fluid” reaction model in which the rate-determining factor is the frequency

An efficient synthesis of a C₁₂-higher sugar aminoalditol

• Łukasz Szyszka,
• Anna Osuch-Kwiatkowska,
• Mykhaylo A. Potopnyk and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2017, 13, 2146–2152, doi:10.3762/bjoc.13.213

• , 6.72; N, 0.88. To a stirred solution of 8 (0.35 g, 0.21 mmol) in DMF (20 mL) containing imidazole (1.5 mg), sodium hydride (60% dispersion in mineral oil, 80.6 mg, 2.1 mmol) was added, and the mixture was stirred at 20 °C for 30 min. Benzyl bromide (0.2 mL, 1.68 mmol) was added dropwise and the mixture

NHC-catalyzed cleavage of vicinal diketones and triketones followed by insertion of enones and ynones

• Ken Takaki,
• Makoto Hino,
• Akira Ohno,
• Kimihiro Komeyama,
• Hiroto Yoshida and
• Hiroshi Fukuoka

Beilstein J. Org. Chem. 2017, 13, 1816–1822, doi:10.3762/bjoc.13.176

• regeneration of C and its reaction with 6a took place predominantly. It seems surprising that compound 12 could be quantitatively generated from C and HClO4 regardless of equimolar amounts of DIPEA, while analogous intermediates derived from imidazole NHC were protonated by the acid alone [23]. Conclusion We

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• facilitates the asymmetric intramolecular cycloetherification of starting materials 27 (Scheme 13). One of the important observations in this impressive report was the necessity of the imidazole moiety to achieve high selectivities [125]. In a subsequent study, the same group also expanded this concept to 6

An efficient Pd–NHC catalyst system in situ generated from Na₂PdCl₄ and PEG-functionalized imidazolium salts for Mizoroki–Heck reactions in water

• Nan Sun,
• Meng Chen,
• Liqun Jin,
• Wei Zhao,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 1735–1744, doi:10.3762/bjoc.13.168

• salt L1, bearing a pyridine-2-methyl substituent at the N3 atom of the imidazole ring, showed the best catalytic activity. Under the optimal conditions, a wide range of substituted alkenes were achieved in good to excellent yields from various aryl bromides and alkenes with the catalyst TON of up to

• reaction sequence as depicted in Scheme 1. Firstly, the commercially available MeO-PEG1900-OH was reacted with MsCl using pyridine as base in CH2Cl2 to form MeO-PEG1900-OMs, which was then treated with sodium imidazole in THF to form the imidazole-functionalized PEG (MeO-PEG1900-Im). The resulted MeO

• –L3 from commercially available MeO-PEG1900-OH, imidazole, and various arylmethyl bromides (2-bromomethylpyridine for L1, benzyl bromide for L2 and 1-bromomethylnaphthalene for L3). It was shown that these imidazolium salts L1–L3 could be utilized as water soluble NHC ligand precursors in combination

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

• . In a first step the PIL block is synthesized using 1-vinyl-3-cyanomethylimidazolium bromide (1) as an IL monomer, which was prepared following a literature procedure [16]. During this process the nitrogen atom in the imidazole ring in position 3 is quaternized. Monomer 1 was polymerized with 2

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Direct catalytic arylation of heteroarenes with meso-bromophenyl-substituted porphyrins

• Alexei N. Kiselev,
• Olga K. Grigorova,
• Alexei D. Averin,
• Sergei A. Syrbu,
• Oskar I. Koifman and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2017, 13, 1524–1532, doi:10.3762/bjoc.13.152

• date certain tetrapyrrole derivatives of such type were described in the literature, for example, porphyrins with imidazole and benzimidazole substitutents at meso-positions [6][7], meso-pyridinyl and meso-quinolinyl-substituted porphyrins [8], an imidazolyl group was attached to the meso-position also

Synthesis of the heterocyclic core of the D-series GE2270

• Christophe Berini,
• Thibaut Martin,
• Pierrik Lassalas,
• Francis Marsais,
• Christine Baudequin and
• Christophe Hoarau

Beilstein J. Org. Chem. 2017, 13, 1407–1412, doi:10.3762/bjoc.13.137

• of chiral thioamide 16. Reaction conditions: a) SnCl2∙2H2O, dioxane/H2O (1:3), 0 °C to rt, 5 h, then NaHCO3, benzyl chloroformate, rt, 18 h, 96%. b) TBDMSCl, imidazole, DMF, rt, 16 h, 99%. c) LiOH∙H2O, DME/H2O (1:1), 0 °C to rt, 72 h, then HCl, 96%. d) DCC, HOSu, THF, rt, 16 h, then Lawesson’s

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

• modern protecting-group-free synthesis (Scheme 29) [89]. The Hindsgaul group reacted imidazole and DMC to form an activated species termed 2-imidazolyl-1,3-dimethylimidazolinium chloride (ImIm) which reacted with UMP within one hour to form an activated phosphoester. Then, over 18 h at 37 °C, Gal-1-P can

Synthesis of D-manno-heptulose via a cascade aldol/hemiketalization reaction

• Yan Chen,
• Xiaoman Wang,
• Junchang Wang and
• You Yang

Beilstein J. Org. Chem. 2017, 13, 795–799, doi:10.3762/bjoc.13.79

• was subjected to benzoyl chloride and DMAP in dichloromethane at room temperature or tert-butyldimethylsilyl chloride and imidazole in DMF at room temperature, no reaction occurred probably because of the steric hindrance between the 2-OH group and the surrounding functional groups. To overcome the

Synthesis of new pyrrolidine-based organocatalysts and study of their use in the asymmetric Michael addition of aldehydes to nitroolefins

• Alejandro Castán,
• Ramón Badorrey,
• José A. Gálvez and
• María D. Díaz-de-Villegas

Beilstein J. Org. Chem. 2017, 13, 612–619, doi:10.3762/bjoc.13.59

• catalytic Pd/C. In this way organocatalysts OC3–OC10 were obtained (Scheme 3 and Scheme 4). In addition another new organocatalyst, OC11, with a different bulky substituent at C2 in the pyrrolidine moiety was prepared. Reacting diol 7 with 1,3-dichlorotetraisopropyldisiloxane in the presence of imidazole

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• synthesized a series of novel imidazole-based phosphine ligands, and their effciency was carefully screened [23]. Among these ligands, the one with two isopropyl groups located at the phenyl ring (L3) was effective in converting aryl chlorides and bromides to the corresponding phenols in moderate to excellent

• structural motifs. Hydroxylation of aryl halides using biphenylphosphine as ligand. Hydroxylation of aryl halides using tert-butylphosphine as ligand. Hydroxylation of aryl halides using imidazole typed phosphine ligands. [Pd(cod)(CH2SiMe3)2] catalyzed hydroxylation of aryl halides. Pd/PANI catalyzed

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

• and noradrenaline. A new method for the synthesis of the indane 2-imidazole derivative 37 acting as a strong adrenergic receptor agonist has been proposed by Roberts et al. [30]. In this synthesis, the diacid 34 was converted to 1-indanone 36 via the AlCl3 promoted Friedel–Crafts acylation of the acid

• carbene is an outstanding protocol for the synthesis of polyhydroxylated spiro- or fused 1-indanones [49]. Thus, the imidazole-based carbene catalyzed the conversion of phthalaldehydes 72 to dihydroxyspiro[indane-2,1′-isobenzofuran]-3-ones 73, whereas triazole-based carbene catalyzed the conversion of 72

Structure–efficiency relationships of cyclodextrin scavengers in the hydrolytic degradation of organophosphorus compounds

• Sophie Letort,
• Michaël Bosco,
• Benedetta Cornelio,
• Frédérique Brégier,
• Sébastien Daulon,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2017, 13, 417–427, doi:10.3762/bjoc.13.45

• iodosobenzoate group, responsible for its degradation, the latter group had to be covalently bound to the cyclodextrin scaffold. Although the presence of the α nucleophile iodosobenzoate was a determinant in the hydrolysis process, an imidazole group was added to get a synergistic effect towards the degradation

• nucleophilic groups were described [31][32]. Recently, our team developed a synthesis of heterodifunctionalized β-CD derivatives bearing an iodosobenzoate group and an imidazole substituent [33]. We have proven that the presence of both substituents increased the detoxification rate of soman as compared to the

• monofunctionalized derivatives. However, the synergistic effect was regiodependent and only observed with the imidazole substituent located in position 2 of one methylated glucose unit and the α nucleophile in position 3 of the adjacent methylated glucose unit (compound 1, Figure 2). Herein we present an extended

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• , 82%; (b) NIS, TfOH, HO(CH2)5NBnCbz, CH2Cl2, −20 °C, 70%; (c) N2H4, AcOH, pyridine, CH2Cl2, 70%; (d) Tf2O, pyridine, CH2Cl2, 0 °C to rt. Synthesis of mannosazide building block 18. Reagents and conditions: (a) TBSCl, imidazole, DCM, 0 °C to rt, 85%; (b) NIS, TfOH, HO(CH2)5NBnCbz, CH2Cl2, −20 °C, 61

• ), −20 °C, 61%; (e) p-TsOH, CH3OH, rt, 90%; (f) TBSCl, imidazole, CH2Cl2, rt, 93%. Synthesis of monosaccharide building blocks 8, 9 and 26. Reagents and conditions: (a) acetic anhydride, pyridine, CH2Cl2, rt, 18 h, 82%; (b) NIS, THF/H2O (1:1), rt; (c) 1) TBDPSCl, imidazole, DMF, rt; 2) NaOMe, MOH, rt, 68

Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

• Andrea Mascitti,
• Massimiliano Lupacchini,
• Ruben Guerra,
• Ilya Taydakov,
• Lucia Tonucci,
• Nicola d’Alessandro,
• Frederic Lamaty,
• Jean Martinez and
• Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 19–25, doi:10.3762/bjoc.13.3

• here that the crude mixture was cleaner in comparison with dry-grinding conditions. Indeed, the symmetrical urea of the starting amino ester – obtained from the corresponding N-carbamoyl imidazole amino ester A – was not observed, as shown by the LC–MS analyses of the crude mixture. An approach

First DMAP-mediated direct conversion of Morita–Baylis–Hillman alcohols into γ-ketoallylphosphonates: Synthesis of γ-aminoallylphosphonates

• Marwa Ayadi,
• Haitham Elleuch,
• Emmanuel Vrancken and
• Farhat Rezgui

Beilstein J. Org. Chem. 2016, 12, 2906–2915, doi:10.3762/bjoc.12.290

• yields and selectivity, using cyclic MBH acetates as starting materials, in the presence of DMAP or imidazole as additives (Scheme 2, reaction 6). Moreover, it has been demonstrated that the presence of a nitrogen atom and a phosphonate moiety in multifunctional compounds may improve their synthetic and

Biochemical and structural characterisation of the second oxidative crosslinking step during the biosynthesis of the glycopeptide antibiotic A47934

• Veronika Ulrich,
• Clara Brieke and
• Max J. Cryle

Beilstein J. Org. Chem. 2016, 12, 2849–2864, doi:10.3762/bjoc.12.284

• expression was induced with 0.1% rhamnose and 0.1 mM IPTG. After overnight expression, cells were harvested at 5000g and 4 °C for 10 min and resuspended in lysis buffer (50 mM Tris pH 8, 50 mM NaCl, 10 mM imidazole, 0.5 mM DTE, EDTA-free SIGMAFAST™ Protease Inhibitor Cocktail Tablet). All purification steps

• -terminally hexahistidine-tagged StaF. Therefore, the Protino® Ni-NTA Agarose resin (Macherey-Nagel, Düren, Germany) was equilibrated twice with the 10-fold column bed volume (CV) of Ni-NTA wash buffer (50 mM Tris pH 8, 300 mM NaCl, 10 mM imidazole). This was achieved through resuspension of the resin in the

• (50 mM Tris pH 8, 300 mM NaCl, 300 mM imidazole). For anion exchange chromatography (AEC), the Ni-NTA elution was buffer exchanged with AEC buffer A (see below) using illustra NAP-25 columns (GE Healthcare, Chalfont St Giles, UK) and concentrated using vivaspin® centrifugal concentrators with a 30 kDa

Orthogonal protection of saccharide polyols through solvent-free one-pot sequences based on regioselective silylations

• Serena Traboni,
• Emiliano Bedini and
• Alfonso Iadonisi

Beilstein J. Org. Chem. 2016, 12, 2748–2756, doi:10.3762/bjoc.12.271

• ][13]. A regioselective silylation of polar saccharide polyols is typically performed with the appropriate silyl chloride in the presence of a high boiling solvent such as DMF or pyridine, often in the presence of a nucleophilic catalyst (more frequently imidazole and DMAP) [14][15][16][17][18][19][20