Oligonucleotide analogues with cationic backbone linkages

• Melissa Meng and
• Christian Ducho

Beilstein J. Org. Chem. 2018, 14, 1293–1308, doi:10.3762/bjoc.14.111

• accessible by means of chemical synthesis, which is either based on the application of H-phosphonate (for i) or phosphoramidite-based (for iv) DNA synthesis, or on a massively modified version of DNA synthesis (for ii and iii), or on solid phase-supported peptide synthesis (for iv). Studies on the properties

Synthetic avenues towards a tetrasaccharide related to Streptococcus pneumonia of serotype 6A

• Aritra Chaudhury,
• Mana Mohan Mukherjee and
• Rina Ghosh

Beilstein J. Org. Chem. 2018, 14, 1095–1102, doi:10.3762/bjoc.14.95

• conjugate in proper amounts for future vaccine development can only be met via chemical synthesis. Therefore, a number of syntheses targeting the SPn 6A tetrasaccharide has been reported in literature. Initial reports of a linear synthesis were made by Vliegenthart et al. in the nineties [17][18][19][20][21

Volatiles from the xylarialean fungus Hypoxylon invadens

• Jeroen S. Dickschat,
• Tao Wang and
• Marc Stadler

Beilstein J. Org. Chem. 2018, 14, 734–746, doi:10.3762/bjoc.14.62

• Geniculosporium sp. by comparison of the natural products to all possible regioisomers that were obtained by chemical synthesis [9]. Here we report on the identification of the volatiles emitted by the xylarialean fungus Hypoxylon invadens MUCL 54175, a highly interesting pyrenomycete that was recently described

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• demonstrated the specific features which make these nanoreactors an advantageous choice for chemical synthesis. In particular, they combine a high active surface area with a good dispersion in solution and therefore are ideal structures for facile diffusion of reactants. Furthermore, the compartments protect

Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review

• Fabio Tonin and
• Isabel W. C. E. Arends

Beilstein J. Org. Chem. 2018, 14, 470–483, doi:10.3762/bjoc.14.33

• in this review. C12 Dehydroxylation Chemical dehydroxylation UDCA can be obtained by a multistep chemical synthesis starting from CA. Two main steps are involved: the dehydroxylation at C12 and the epimerization of the 7-OH group. In order to achieve chemical dehydroxylation, firstly CA has to be

• processing For an economically and environmentally sustainable process volumetric productivities have to be considered. In other words substrate loadings cannot be too low. While it does not represent a problem in chemical synthesis (UDCA, CDCA and CA are pretty soluble in alcohols like methanol and ethanol

Stimuli-responsive oligonucleotides in prodrug-based approaches for gene silencing

• Françoise Debart,
• Christelle Dupouy and
• Jean-Jacques Vasseur

Beilstein J. Org. Chem. 2018, 14, 436–469, doi:10.3762/bjoc.14.32

• synthesis and properties of 2’-O-alkyldithiomethyl-modified RNAs [15][16]. Previously, Urata had described a post-synthetic approach for the synthesis of 2’-O-methyldithiomethyl (MDTM) ONs [17] that was more practical than the phosphoramidite approach used initially for the chemical synthesis of RNAs using

Diels–Alder cycloadditions of N-arylpyrroles via aryne intermediates using diaryliodonium salts

• Huangguan Chen,
• Jianwei Han and
• Limin Wang

Beilstein J. Org. Chem. 2018, 14, 354–363, doi:10.3762/bjoc.14.23

• Huangguan Chen Jianwei Han Limin Wang Key Laboratory for Advanced Materials, Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China Shanghai–Hong Kong Joint Laboratory in Chemical

• Synthesis, Shanghai Institute of Organic Chemistry, The Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China 10.3762/bjoc.14.23 Abstract With a strategy of the formation of benzynes by using diaryliodonium salts, a cycloaddition reaction of N-arylpyrroles with benzynes was reported. A

Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)

• Tao Wang,
• Kathrin I. Mohr,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9

• significant activities against competing microbes, but the volatile profiles of these biocontrol candidates were only evaluated using databases like NIST, which can only serve to detect and identify known compounds. The current study demonstrates the need of chemical synthesis for rigorous identification of

Aminosugar-based immunomodulator lipid A: synthetic approaches

• Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

• diglucosamine backbone. Strong controversies in assessment of biological activities of P. gingivalis lipid A based on the LPS isolates [95][96][97] prompted chemical synthesis of structurally defined variably acylated P. gingivalis lipid A substructures [98][99]. Tetraacylated lipid A substructures representing

Synthetic mRNA capping

• Fabian Muttach,
• Nils Muthmann and
• Andrea Rentmeister

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

• for introduction of other artificial cap analogues at the 5′-end aiming to modulate biological activity of the resulting RNAs. Enzymatic modification of chemically synthesized cap analogues An alternative to the complete chemical synthesis of cap analogues is the use of enzymes to functionalize

• adenosyltransferase variant (MAT-Var.). The AdoMet analogue was directly converted by the methyltransferases, resulting in double alkyne modified cap analogues [95]. Chemical synthesis of capped mRNA Solid-phase synthesis of capped RNA Chemical synthesis of capped RNA is based on the solid-phase synthesis of RNA

• nucleotides and was prepared with the 2-cyanoethoxymethyl (CEM) as the 2′-OH protection group [105]. Chemical synthesis of 5′-capped RNA in solution was originally reported to be low yielding, slow (reaction times of 6–10 days), and not suitable for large-scale preparations [58][106][107][108][109][110

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

• [6][7] to catalysis [8][9] and drug carriers [10][11][12][13]. Unlike the more popular cyclodextrins (CDs), CAs are exclusively obtained by chemical synthesis [14][15][16][17][18]. Therefore, they are particularly suitable for designing tailored systems with peculiar properties and abilities. This

A semisynthesis of 3'-O-ethyl-5,6-dihydrospinosyn J based on the spinosyn A aglycone

• Kai Zhang,
• Shenglan Liu,
• Anjun Liu,
• Hongxin Chai,
• Jiarong Li and
• Lamusi A

Beilstein J. Org. Chem. 2017, 13, 2603–2609, doi:10.3762/bjoc.13.257

• aglycone are obtained via the hydrolysis of spinosyn A. High yields were obtained in each step, and all intermediates in the synthesis were characterized by 1H NMR, 13C NMR and MS techniques. This study can be helpful for developing an efficient chemical synthesis of spinetoram, and it also offers

• ][20][21][22], but there are few studies on the chemical synthesis of 3'-O-ethyl-5,6-dihydrospinosyn J. Considering the high fermentation productivity and low cost of spinosyn A, we designed a semi-synthesis of 3'-O-ethyl-5,6-dihydrospinosyn J from the spinosyn A aglycone via sequential glycosylation

Hydrolysis, polarity, and conformational impact of C-terminal partially fluorinated ethyl esters in peptide models

• Vladimir Kubyshkin and
• Nediljko Budisa

Beilstein J. Org. Chem. 2017, 13, 2442–2457, doi:10.3762/bjoc.13.241

• experiments are remarkably sensitive [4]. Fluorine-containing groups can be incorporated into biopolymers by various approaches, including those that utilize biosynthesis [5][6][7], enzymatic conversion [8], chemical synthesis [9][10], and ligation reactions [11]. Depending on the research target, 19F NMR

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• development of medicinal chemistry and demands of the pharmaceutical industry for greener and more efficient approaches to chemical synthesis [23][24][25]. In accordance with the progress of mechanochemistry in organic syntheses [26], ball milling has been successfully implemented for solvent-free CuAAC

Synthesis of ergostane-type brassinosteroids with modifications in ring A

• Vladimir N. Zhabinskii,
• Darya A. Osiyuk,
• Yuri V. Ermolovich,
• Natalia M. Chaschina,
• Tatsiana S. Dalidovich,
• Miroslav Strnad and
• Vladimir A. Khripach

Beilstein J. Org. Chem. 2017, 13, 2326–2331, doi:10.3762/bjoc.13.229

• understood. Evidently, the identification of as much as possible elements of this network would contribute to its better knowledge. Because of the extremely low BS content in natural sources, studies on their identification almost always included a preliminary chemical synthesis of the compounds in question

Comparative profiling of well-defined copper reagents and precursors for the trifluoromethylation of aryl iodides

• Peter T. Kaplan,
• Jessica A. Lloyd,
• Mason T. Chin and
• David A. Vicic

Beilstein J. Org. Chem. 2017, 13, 2297–2303, doi:10.3762/bjoc.13.225

• complexes of copper B1 were reported shortly after the NHC counterparts [5][12] and have reached much success in chemical synthesis due to the ease of preparation and the low cost of the phenanthroline ancillary ligand. [(phen)CuCF3] can now be purchased commercially, or prepared in situ by a variety of

Synthesis of 2-aminosuberic acid derivatives as components of some histone deacetylase inhibiting cyclic tetrapeptides

• Shital Kumar Chattopadhyay,
• Suman Sil and
• Jyoti Prasad Mukherjee

Beilstein J. Org. Chem. 2017, 13, 2153–2156, doi:10.3762/bjoc.13.214

• [5][6]. For this, and other reasons, several synthetic routes to Asu have been developed [7][8][9] which often uses chemical or enzymatic resolution of a racemate [10]. However, the chemical synthesis of an orthogonally protected Asu derivative from easily available sources [11] for potential

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• needed [3]. However, this is hampered by the limited availability of complex glycans from nature. Thus, chemical synthesis is a powerful approach to provide much needed samples to enable biological studies [4]. Traditional carbohydrate synthesis is commonly carried out from the reducing end to the non

• °C; then acceptor. Chemoselective iterative dehydrative glycosylation. Reagents and conditions: (a) Ph2SO, Tf2O, −40 °C. Chemical synthesis of a hyaluronic acid (HA) trimer 47. Reagents and conditions: (a) Ph2SO, TTBP, CH2Cl2, −60 °C, then Tf2O, 44, −60 °C to 0 °C; (b) Ph2SO, TTBP, CH2Cl2, −60 °C

Main group mechanochemistry

• Agota A. Gečiauskaitė and
• Felipe García

Beilstein J. Org. Chem. 2017, 13, 2068–2077, doi:10.3762/bjoc.13.204

• methodologies. Mechanochemistry [1][2][3][4][5][6][7][8][9][10] is an emerging solid state methodology involving the use of little or no solvent, with the potential to challenge the current dominance of ‘wet’ chemical synthesis [11][12][13][14][15]. From a purely synthetic point of view, it is clear that

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• remote glycosidation of 18 was conducted in the presence of Cp2HfC12 and AgOTf in CH2C12 under reflux. The cyclized product 19 was obtained in 37% yield, the tether was removed with NaOMe, and the resulting free hydroxy groups were acetylated to afford the branched trisaccharide 20. The chemical

• synthesis of cyclodextrins is very challenging: controlling α-gluco stereoselectivity, and especially the final cyclization, represent a great challenge. For example, in Ogawa’s synthesis of α-cyclodextrin the chain assembly was non-stereoselective and the cyclization was achieved in only 21% yield [75

One-pot multistep mechanochemical synthesis of fluorinated pyrazolones

• Joseph L. Howard,
• William Nicholson,
• Yerbol Sagatov and
• Duncan L. Browne

Beilstein J. Org. Chem. 2017, 13, 1950–1956, doi:10.3762/bjoc.13.189

• ; mechanochemistry; multistep; solid-state synthesis; Introduction Mechanochemical methods are emerging as an alternative approach to traditional solvent-based reactions for chemical synthesis. Under mechanochemical conditions reactions are performed between neat reagents and do not require a solvent. Processing

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

• fortunately, mechanochemistry has overcome all these limitations and proved to be advantageous since it uses minimum amount of solvents, shorter reaction time, and easy handling of reagents and room temperature conditions. Despite the advantages of ball milling in chemical synthesis still there are some

Grip on complexity in chemical reaction networks

• Albert S. Y. Wong and
• Wilhelm T. S. Huck

Beilstein J. Org. Chem. 2017, 13, 1486–1497, doi:10.3762/bjoc.13.147

• exploit the full power of chemical synthesis. Figure 7a depicts the synthetic sites at which the pro-inhibitor can be altered (R1−R4). In general, this allows us to create a “Swiss army knife” out of the source molecule that controls the negative feedback [30]. The possibility to make small synthetic

Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

• Ana Franco,
• Sudipta De,
• Alina M. Balu,
• Araceli Garcia and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1439–1445, doi:10.3762/bjoc.13.141

• Singapore, 4 Engineering Drive 4, 117585, Singapore 10.3762/bjoc.13.141 Abstract Vanillin is one of the most commonly used natural products, which can also be produced from lignin-derived feedstocks. The chemical synthesis of vanillin is well-established in large-scale production from petrochemical-based

Synthesis of oligonucleotides on a soluble support

• Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

• ion labile tert-butyldimethylsilyl (TBDMS) [20]) and triisopropylsilyloxymetyl (TOM) [21] groups being most widely used. Otherwise, the synthetic strategies are similar to those of ODNs. The real breakthrough of the chemical synthesis of oligonucleotides was the finding of Beaucage and Caruthers in