Automated glycan assembly of arabinomannan oligosaccharides from Mycobacterium tuberculosis

• Alonso Pardo-Vargas,
• Priya Bharate,
• Martina Delbianco and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2019, 15, 2936–2940, doi:10.3762/bjoc.15.288

• the understanding of these polysaccharides and the development of novel therapeutical and diagnostic agents. Automated glycan assembly (AGA) was employed to prepare the core structure of AM from MTB, containing α-(1,6)-Man, α-(1,5)-Ara, and α-(1,2)-Man linkages. The introduction of a capping step

• after each glycosylation and further optimized reaction conditions allowed for the synthesis of a series of oligosaccharides, ranging from hexa- to branched dodecasaccharides. Keywords: arabinomannan; automated glycan assembly; capping; Introduction Bacterial infections caused by MTB killed 1.7

• Mai Hoang for the proofreading of the manuscript. This work used Dr. Bharate’s thesis “Automated Glycan Assembly of Oligomannose Glycans for Sensing Applications” as a source.

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

• László Orha,
• József M. Tukacs,
• László Kollár and
• László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

• chemistry; ionic liquids; Introduction In the past few decades, the transition-metal-catalyzed coupling reaction has represented one of the most powerful and atom economical strategies for the efficient assembly of new carbon–carbon bonds. It has therefore become the most attractive approach to the

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering

• Eric J. N. Helfrich,
• Geng-Min Lin,
• Christopher A. Voigt and
• Jon Clardy

Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283

• knowledge of how they are biosynthesized is limited, particularly when compared to the well-studied thiotemplate assembly lines. Bacteria have only recently been recognized as having the genetic potential to biosynthesize a large number of complex terpenoids, but our current ability to associate genetic

• thiotemplated assembly lines, such as type I polyketide synthases (PKS) and nonribosomal peptide synthetases (NRPS), are modular, with each module contributing a distinct fragment to the final product’s core structure – a short-chain carboxylic acid (PKS) or an amino acid (NRPS). The modularly defined template

• . Biosynthetic core enzymes of well-characterized classes of natural products, such as modular thiotemplate assembly lines (NRPSs, PKSs), are usually highly specific and produce only a few closely related natural product analogs. Adenylation domains in NRPSs [26][27][28], acyltransferase (AT) domains in cis-AT

Influence of the cis/trans configuration on the supramolecular aggregation of aryltriazoles

• Sara Tejera,
• Giada Caniglia,
• Rosa L. Dorta,
• Andrea Favero,
• Javier González-Platas and
• Jesús T. Vázquez

Beilstein J. Org. Chem. 2019, 15, 2881–2888, doi:10.3762/bjoc.15.282

• - and cis-1,2-glucopyranosyl and cyclohexyl ditriazoles, synthesized by CuAAC "click" chemistry, to form gels was studied, their physical properties determined, and the self-aggregation behavior investigated by SEM, X-ray, and EDC studies. The results revealed that self-assembly was driven mainly by π–π

• , with short and planar films or scales. This could be due to the high proportion of water in the gel and/or the presence of the three free hydroxy groups in its structure, changing its intermolecular self-assembly behavior. Various efforts were made to crystallize the obtained compounds; however, only

A chiral self-sorting photoresponsive coordination cage based on overcrowded alkenes

• Constantin Stuckhardt,
• Diederik Roke,
• Wojciech Danowski,
• Edwin Otten,
• Sander J. Wezenberg and
• Ben L. Feringa

Beilstein J. Org. Chem. 2019, 15, 2767–2773, doi:10.3762/bjoc.15.268

• be expected when the homochiral enantiomers of cage structure Pd2(stable Z-1)4 are the only optically active species in solution (Figure S1, Supporting Information File 1). Additionally, DOSY NMR spectroscopy revealed that the signals correspond to a single type of assembly in each case (see

• formation of a new set of signals was observed. DOSY NMR confirmed the formation of an assembly with a hydrodynamic radius which was similar to that of the cage Pd2(stable Z-1)4. Precipitation of the metal centers in this assembly using tetrabutylammonium glutarate liberates the ligands and they were

Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

• Heather J. Lacey,
• Cameron L. M. Gilchrist,
• Andrew Crombie,
• John A. Kalaitzis,
• Daniel Vuong,
• Peter J. Rutledge,
• Peter Turner,
• John I. Pitt,
• Ernest Lacey,
• Yit-Heng Chooi and
• Andrew M. Piggott

Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256

• is synthesised by a PKS [32]. The A. nanangensis genome was sequenced and a draft assembly of the genome was generated. A local BLASTp search of the A. nanangensis genome using the drimane synthase AstC as query returned a hit on scaffold 3, FE257_006542, which was immediately flanked by a highly

• . insuetus CBS 107.25 (Figure 2). A homologous cluster was also found in A. pseudodeflectus CBS 756.74, though it is located on a truncated assembly scaffold. In total, six genes are conserved across these species: the HR-PKS (FE257_006541), HAD-like terpene synthase (FE257_006542) and FAD-binding

• and bioinformatic analysis Genomic DNA was extracted from A. nanangensis (see Supporting Information File 1) and sent to the Australian Genome Research Facilities for de novo genome sequencing using Illumina HiSeq 2000. A draft genome assembly of A. nanangensis was obtained using SPAdes v3.13.0 via

Safe and highly efficient adaptation of potentially explosive azide chemistry involved in the synthesis of Tamiflu using continuous-flow technology

• Cloudius R. Sagandira and
• Paul Watts

Beilstein J. Org. Chem. 2019, 15, 2577–2589, doi:10.3762/bjoc.15.251

• firm that specialises in azide chemistry to develop its industrial process [1][2][6][9]. Numerous reported routes demonstrate amazing potential and ingenuity in the Tamiflu molecule assembly. However, most of them are not amenable to easy scale-up due to the safety concerns associated with azide

Chemical synthesis of the pentasaccharide repeating unit of the O-specific polysaccharide from Escherichia coli O132 in the form of its 2-aminoethyl glycoside

• Debasish Pal and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2019, 15, 2563–2568, doi:10.3762/bjoc.15.249

• -acetylation using NaOMe in MeOH followed by hydrogenolysis in a ThalesNano continuous flow hydrogenation assembly using a 10% Pd-C cartridge [29]. After three cycles of hydrogenation, formation of the target pentasaccharide 1 was evident from the mass spectrum (Scheme 4). Conclusion In conclusion, the

Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis

• Zhen Cao,
• Aline Lacoudre,
• Cybille Rossy and
• Brigitte Bibal

Beilstein J. Org. Chem. 2019, 15, 2465–2472, doi:10.3762/bjoc.15.239

• the stoichiometry of coordination complexes. Atropisomer 1 directed the self-assembly towards the same half-space (regarding the anthracene core). The triflate anion lead to a [2 + 2] macrocycle meanwhile the more coordinating nitrate anion induced the formation of a large globular macrocycle M6L4. A

Reversible switching of arylazopyrazole within a metal–organic cage

• Anton I. Hanopolskyi,
• Soumen De,
• Michał J. Białek,
• Yael Diskin-Posner,
• Liat Avram,
• Moran Feller and
• Rafal Klajn

Beilstein J. Org. Chem. 2019, 15, 2398–2407, doi:10.3762/bjoc.15.232

• selectivity [35][36][37][38][39][40]. Consequently, arylazopyrazoles have been employed as photoresponsive gelators [41] and adhesives [42] and for controlling antimicrobial response [43][44], cell adhesion to surfaces [45], as well as DNA [46] and microtubule [47] self-assembly using light. Here, we focused

Targeted photoswitchable imaging of intracellular glutathione by a photochromic glycosheet sensor

• Xianzhi Chai,
• Hai-Hao Han,
• Yi Zang,
• Jia Li,
• Xiao-Peng He,
• Junji Zhang and
• He Tian

Beilstein J. Org. Chem. 2019, 15, 2380–2389, doi:10.3762/bjoc.15.230

• , indicating the successful coating of MnO2 nanosheets with the Glyco-DTE reporter [25]. An increasing Zeta potential was also observed after the assembly, confirming again the successful fabrication of Glyco-DTE@MnO2 glycosheet (Figure 2D) [26]. GSH sensing and fluorescence photoswitching of Glyco-DTE@MnO2

1,2,3-Triazolium macrocycles in supramolecular chemistry

• Mastaneh Safarnejad Shad,
• Pulikkal Veettil Santhini and
• Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

• template-directed self-assembly procedure via an intramolecular “CuAAC click” reaction in the presence of electron-rich bisnaphtho- or bisbenzo-24-crown-8 ethers. Afterwards, the triazole groups in the catenanes were methylated. The resulting triazolium macrocycle containing catenanes 17a (DN24C8) and 17b

• interactions, compared to monovalent receptor–ligand interactions offer the advantage of multiple and sequential binding within the host–guest systems. These noncovalent interactions which can be controlled in a chemical or physical manner depend on the binding sites in the multivalent assembly [67

Multiple threading of a triple-calix[6]arene host

• Veronica Iuliano,
• Roberta Ciao,
• Emanuele Vignola,
• Carmen Talotta,
• Patrizia Iannece,
• Margherita De Rosa,
• Annunziata Soriente,
• Carmine Gaeta and
• Placido Neri

Beilstein J. Org. Chem. 2019, 15, 2092–2104, doi:10.3762/bjoc.15.207

• stereoselective formation of endo-alkyl pseudo[n]rotaxane stereoisomers. Keywords: calixarene; multiple-threading; pseudo[n]rotaxane; stereoisomers; Introduction The self-assembly [1] of smaller components to larger aggregates represents one of the most spectacular phenomena in supramolecular chemistry [2][3][4

• ]. Among the self-assembly processes, those that lead to the formation of interlocked and/or interpenetrated supramolecular structures have inspired many scientists [5][6][7][8]. The synthesis of interlocked molecules such as rotaxanes, catenanes, and high-order architectures (e.g., polyrotaxanes, suitanes

Naphthalene diimides with improved solubility for visible light photoredox catalysis

• Barbara Reiß and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 2043–2051, doi:10.3762/bjoc.15.201

• self-assembly [43][44], as molecular sensors [45][46][47] and for organic electronics [48][49], but yet nearly completely unexplored for photoredox catalysis. Core-unsubstituted NDIs are colorless compounds with high extinction coefficients at the border between UV-A and visible light. Their

Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via intramolecular 1,3-dipolar cycloaddition

• Yulia V. Khoroshunova,
• Denis A. Morozov,
• Andrey I. Taratayko,
• Polina D. Gladkikh,
• Yuri I. Glazachev and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2019, 15, 2036–2042, doi:10.3762/bjoc.15.200

• effect may be useful for structural studies by means of PELDOR or DQC [5]. We recently reported the synthesis of sterically shielded pyrrolidine nitroxide 1 via a stereospecific consecutive assembly of two spiro-(2-hydroxymethyl)cyclopentane moieties. These procedures included the addition of pent-4

• of nitroaldehyde 3c (25%). The reactive aldehyde groups were protected via 1,3-dioxolane assembly, and the resulting compounds were treated with Zn dust and NH4Cl in a water–THF solution to reduce nitro groups. The resulting hydroxylamines were treated with hydrochloric acid to hydrolyse dioxolane

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

• molecular systems to study molecular recognition and the nature of noncovalent interactions. Functional macrocycles also provide essential components for the fabrication or assembly of sophisticated (supra)molecular structures [1][2][3][4], advanced materials [1][2][5][6][7][8][9][10] and machinery systems

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

• -responsive supramolecular self-assemblies have been constructed, the controlled drug delivery induced by morphology transitions of these supramolecular self-assemblies on the basis of host–guest-conjugated monomers (HGCMs) are few reported. In this paper, the self-assembly behaviors of AB2-type HGCMs, e.g

• stimuli-responsive supramolecular self-assemblies with regulated self-assembly morphologies due to their response to various external stimuli, such as temperature [12], light [13][14][15], redox [16][17][18], and pH [19][20]. In addition, β-cyclodextrin (β-CD), pillararene and cucurbituril have been

• -assemblies were fairly complicated, and their self-assembly behaviors could hardly effectively be regulated. Alternatively, host–guest-conjugated monomers (HGCMs) which gather host and guest units into one molecule have been studied and attracted many attentions in the field of self-assembly [35]. AB-type

Complexation of chiral amines by resorcin[4]arene sulfonic acids in polar media – circular dichroism and diffusion studies of chirality transfer and solvent dependence

• Bartosz Setner and
• Agnieszka Szumna

Beilstein J. Org. Chem. 2019, 15, 1913–1924, doi:10.3762/bjoc.15.187

• Bartosz Setner Agnieszka Szumna Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland 10.3762/bjoc.15.187 Abstract Directional self‐assembly of conformationally well-defined complexes in polar environment is still a major challenge in supramolecular

• disintegrative for these complexes. This result is quite non-intuitive and worth attention in the context of formation of supramolecular complexes in polar environment, for which DMSO is most often a first-choice solvent. Keywords: cavitands; chirality; macrocycle; resorcin[4]arene; self-assembly

• ; supramolecular chemistry; Introduction Despite of the great progress that has been made in supramolecular chemistry in polar and aqueous media, formation of discrete ordered supramolecular associates with precise patterns of noncovalent interactions still presents a challenge [1][2]. Especially self-assembly

Installation of -SO₂F groups onto primary amides

• Jing Liu,
• Shi-Meng Wang,
• Njud S. Alharbi and
• Hua-Li Qin

Beilstein J. Org. Chem. 2019, 15, 1907–1912, doi:10.3762/bjoc.15.186

• aromatic amines with SO2F2 or the fluorosulfurylimidazolium salt have been achieved for assembly of N-sulfonyl fluorides [1][30], which have served as important active precursors for the development of noncovalent inhibitors (Scheme 1, (1)) [1][30][31]. Amides are the key connections in proteins, amides

• assembly of N-fluorosulfonyl amides from cheap and abundant reagent is highly desirable. Herein, we report the first, to the best of our knowledge, SO2F2-mediated N-fluorosulfonylation [40][41][42] of amides by using DBU as base for the constructions of a series N-fluorosulfonyl amides (Scheme 1b). Results

Nanopatterns of arylene–alkynylene squares on graphite: self-sorting and intercalation

• Tristan J. Keller,
• Joshua Bahr,
• Kristin Gratzfeld,
• Nina Schönfelder,
• Marcin A. Majewski,
• Marcin Stępień,
• Sigurd Höger and
• Stefan-S. Jester

Beilstein J. Org. Chem. 2019, 15, 1848–1855, doi:10.3762/bjoc.15.180

• the TCB/HOPG (and also the 1-octanoic acid/HOPG) interface at concentrations as low as 10−3 M or lower (see Supporting Information File 1). Anyhow, the above results motivated us to investigate whether 1a stabilizes the assembly by intercalation of the non-planar species 3. Therefore, we prepared (by

Synthesis of a [6]rotaxane with singly threaded γ-cyclodextrins as a single stereoisomer

• Jason Yin Hei Man and
• Ho Yu Au-Yeung

Beilstein J. Org. Chem. 2019, 15, 1829–1837, doi:10.3762/bjoc.15.177

• building blocks for the construction of complex molecular topology such as rotaxanes and catenanes [12][13][14][15]. For example, by making use of hydrophobic-driven binding of simple alkyl groups in water to α-CD, Ogino has reported one first example of a rotaxane assembly featuring an alkyldiamine

Norbornadiene-functionalized triazatriangulenium and trioxatriangulenium platforms

• Roland Löw,
• Talina Rusch,
• Tobias Moje,
• Fynn Röhricht,
• Olaf M. Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1815–1821, doi:10.3762/bjoc.15.175

• would have to be in the switched state 1b. The second explanation, i.e., that the mixed monolayer consists of octyl-TATA 6 and the NBD-TATA 1a, seems to be more likely, since molecule 1 decays slowly under irradiation in contact with oxygen. Previous measurements have shown that self-assembly from

• solutions containing pure and vertically functionalized TATA molecules leads to the formation of stochastically mixed monolayers with a highly ordered (√19 × √19) R23.4° superstructure [22]. This would be also expected for self-assembly from solution containing 1a and 6. The composition of the adlayer on

Complexation of 2,6-helic[6]arene and its derivatives with 1,1′-dimethyl-4,4′-bipyridinium salts and protonated 4,4'-bipyridinium salts: an acid–base controllable complexation

• Jing Li,
• Qiang Shi,
• Ying Han and
• Chuan-Feng Chen

Beilstein J. Org. Chem. 2019, 15, 1795–1804, doi:10.3762/bjoc.15.173

• methenyl groups. They have been a kind of important macrocyclic host molecules during the last decades due to their unique structures and a wide range of applications in host–guest chemistry [13][14][15][16][17][18], self-assembly [19], biomedicine [20] and materials science [21][22]. The derivatives of

Synthesis, enantioseparation and photophysical properties of planar-chiral pillar[5]arene derivatives bearing fluorophore fragments

• Guojuan Li,
• Chunying Fan,
• Guo Cheng,
• Wanhua Wu and
• Cheng Yang

Beilstein J. Org. Chem. 2019, 15, 1601–1611, doi:10.3762/bjoc.15.164

• center and therefore chirality transfer is non-effective [43]. Supramolecular assembly usually leads to different photophysical properties than homogeneous solutions. We have demonstrated that solvents play a critical role in chiral recognition and chiral photoreactions [44][45][46][47][48][49][50][51

Water inside β-cyclodextrin cavity: amount, stability and mechanism of binding

• Stiliyana Pereva,
• Valya Nikolova,
• Silvia Angelova,
• Tony Spassov and
• Todor Dudev

Beilstein J. Org. Chem. 2019, 15, 1592–1600, doi:10.3762/bjoc.15.163

• “head–tail” assembly of the primary hydroxy groups can be considered as a major attractor (“hot” spot) for the incoming water. Similar results had been obtained for the positioning of the first water molecule hosted by the smaller α-CD counterpart [19]. In constructing the heavier β-CD hydrates