On the mass spectrometric fragmentations of the bacterial sesterterpenes sestermobaraenes A–C

• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2020, 16, 2807–2819, doi:10.3762/bjoc.16.231

• complicated cases, as was exemplified for the side products of bacterial 2-methylisoborneol synthases [22], but in general the structural complexity of terpenes does not allow for such approaches. Nevertheless, more knowledge about the MS fragmentation reactions of terpenes is desirable, but represents a

A heterobimetallic tetrahedron from a linear platinum(II)-bis(acetylide) metalloligand

• Matthias Hardy,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2020, 16, 2701–2708, doi:10.3762/bjoc.16.220

• sophisticated cage-in-ring structures [6][7], interlocked rings [8] and catenanes [9][10][11][12] or giant spheres [13][14]. Increasing the structural complexity, however, usually implies growing synthetic efforts that have to be made to obtain the necessary organic ligands [15][16][17]. A great way to simplify

• complexity with homometallic assemblies becomes increasingly difficult to achieve. An approach to tackle these limitations is the use of not only one, but two different types of metal cations to form heterobimetallic aggregates [24][25][26]. Introducing two different types of metal cations within one

Vicinal difluorination as a C=C surrogate: an analog of piperine with enhanced solubility, photostability, and acetylcholinesterase inhibitory activity

• Yuvixza Lizarme-Salas,
• Alexandra Daryl Ariawan,
• Ranjala Ratnayake,
• Hendrik Luesch,
• Angela Finch and
• Luke Hunter

Beilstein J. Org. Chem. 2020, 16, 2663–2670, doi:10.3762/bjoc.16.216

• predominate. Of course, the contiguous positioning of the F–C–C–F and F–C–C=O moieties within the same molecule (2) means that these moieties would not function independently, but rather would likely influence one another, adding another layer of complexity. Finally, it is interesting to consider whether the

Leveraging glycomics data in glycoprotein 3D structure validation with Privateer

• Haroldas Bagdonas,
• Daniel Ungar and
• Jon Agirre

Beilstein J. Org. Chem. 2020, 16, 2523–2533, doi:10.3762/bjoc.16.204

• complexity of glycans in glycoproteins have been, and currently remain, significant challenges in structural biology. These aspects present unique problems to the two most prolific techniques: X-ray crystallography and cryo-electron microscopy. At the same time, advances in mass spectrometry have made it

• databases can usually be interrogated using textual or graphical notations that describe the glycan sequence. However, due to the glycan complexity and the incremental nature of the different glycomics projects, numerous notations have been developed over the years – e.g., CarbBank [48] utilized CCSD [48

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

• Emine Kayahan,
• Mathias Jacobs,
• Leen Braeken,
• Leen C.J. Thomassen,
• Simon Kuhn,
• Tom van Gerven and
• M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

• sequestration [7]. Still, photochemistry has not been exploited much in industry since the distribution of light inside a photoreactor brings a lot of complexity to the reactor design. Unlike thermochemical reactions, it is not feasible to scale up photoreactions by increasing the dimensions of the reactor due

• successful scale-up strategies in literature. Design considerations The complexity of the photochemical processes leads to significant challenges in the photoreactor design. In addition to the general reactor design considerations, such as the selection of a suitable reactor material and geometry, the

• energy efficiency. In addition, the solvent should not absorb light strongly nor be a quencher of the photoreaction. In order to avoid excessive heating of the light source, cooling systems might be necessary. The distribution of light inside the reactor brings a lot of complexity into the design. Since

Conformational preferences of fluorine-containing agrochemicals and their implications for lipophilicity prediction

• Daniela Rodrigues Silva,
• Joyce K. Daré and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2020, 16, 2469–2476, doi:10.3762/bjoc.16.200

•  5b). Most tools for predicting physicochemical properties are based on the additive contributions of polarity from atoms or chemical groups instead of considering the overall molecular polarity (μ) [27]. The predictive ability of these methods for compounds with higher structural complexity have been

Computational tools for drawing, building and displaying carbohydrates: a visual guide

• Kanhaya Lal,
• Rafael Bermeo and
• Serge Perez

Beilstein J. Org. Chem. 2020, 16, 2448–2468, doi:10.3762/bjoc.16.199

• a continuous development and evolution of the description of monosaccharides [2]. Glycans are puzzles to many chemists, and biologists as well as bioinformaticians. This complexity occurs at different levels (which makes it incremental). Amongst the most recognisable “sugars”, glucose is merely one

• together either linearly or branched); (ii) polysaccharides (for glycan chains composed of more than ten monosaccharides); (iii) glycoconjugates (where the glycan chains are covalently linked to proteins (glycoproteins), lipids (glycolipids). The complexity of glycans is a consequence of their branched

• structure and the range of building blocks available. Other levels of complexity include the nature of the glycosidic linkage (anomeric configuration, position and angles), the number of repeating units (polysaccharides) as well as the substitutions of the monosaccharides. Regardless of the different

A proposed sustainability index for synthesis plans based on input provenance and output fate: application to academic and industrial synthesis plans for vanillin as a case study

• John Andraos

Beilstein J. Org. Chem. 2020, 16, 2346–2362, doi:10.3762/bjoc.16.196

• of such databases requires significant investment in time and energy but once done it is expected that they will have far-reaching utility in the long run. An important point to keep in mind in extending synthesis chains to first generation feedstocks of simple chemical complexity is that

Design and synthesis of a bis-macrocyclic host and guests as building blocks for small molecular knots

• Elizabeth A. Margolis,
• Rebecca J. Keyes,
• Stephen D. Lockey IV and
• Edward E. Fenlon

Beilstein J. Org. Chem. 2020, 16, 2314–2321, doi:10.3762/bjoc.16.192

• trefoil knots have been prepared with an all-hydrocarbon example by the Itami group [7] and the synthesis of a single enantiomer by Leigh’s group [8]. Complexity has also been achieved with recent work showing that eight-crossing knots [9][10][11] and a nine-crossing composite knot can be synthesized [12

Tools for generating and analyzing glycan microarray data

• Akul Y. Mehta,
• Jamie Heimburg-Molinaro and
• Richard D. Cummings

Beilstein J. Org. Chem. 2020, 16, 2260–2271, doi:10.3762/bjoc.16.187

• intricacies involved at multiple levels. Unlike DNA and proteins, glycans are neither linear nor template driven, making their structures computationally taxing. In addition, the complexity is compounded by the sample and experimental meta data associated with the glycan microarray experiment. The following

• comparison of glycan microarray data. We identify a variety of glycan microarray repositories where interested readers can find microarray data to build new software. We also highlight manual and automated data analysis tools. One must always be aware that the intrinsic complexity of the multistep process of

Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

• Poulami Jana,
• Filip Šupljika,
• Carsten Schmuck and
• Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

• molecules were dyes used for the DNA/RNA labelling or even monitoring or influencing DNA/RNA function [3][4]. However, due to the complexity of DNA-coded or RNA-coded processes, also including epigenetics, there is permanent need for novel dyes, differing in selectivity, colour, or method of monitoring [5

GlypNirO: An automated workflow for quantitative N- and O-linked glycoproteomic data analysis

• Toan K. Phung,
• Cassandra L. Pegg and
• Benjamin L. Schulz

Beilstein J. Org. Chem. 2020, 16, 2127–2135, doi:10.3762/bjoc.16.180

• complexity of glycan heterogeneity requires that downstream analysis often involves manual processing in addition to standard informatics workflows. Here, we developed and used GlypNirO, an automated bioinformatic workflow for label-free quantitative N- and O-glycoproteomics that focuses on improving

Clustering and curation of electropherograms: an efficient method for analyzing large cohorts of capillary electrophoresis glycomic profiles for bioprocessing operations

• Ian Walsh,
• Matthew S. F. Choo,
• Sim Lyn Chiin,
• Amelia Mak,
• Shi Jie Tay,
• Pauline M. Rudd,
• Yang Yuansheng,
• Andre Choo,
• Ho Ying Swan and
• Terry Nguyen-Khuong

Beilstein J. Org. Chem. 2020, 16, 2087–2099, doi:10.3762/bjoc.16.176

• . This can be caused by a combination of sample complexity, temperature, pH, day of analysis, and other physicochemical fluctuations during the operation of the analysis. Although GU calculation can help solve this for the qualitative analysis, there is still difficulty automating peak picking due to

How and why plants and human N-glycans are different: Insight from molecular dynamics into the “glycoblocks” architecture of complex carbohydrates

• Carl A. Fogarty,
• Aoife M. Harbison,
• Amy R. Dugdale and
• Elisa Fadda

Beilstein J. Org. Chem. 2020, 16, 2046–2056, doi:10.3762/bjoc.16.171

• invoked when discussing other biopolymers or complex carbohydrates. In the specific case of glycans, the structural complexity, in terms of the diversity of monosaccharides, the linkages’ stereochemistry and the branched scaffolds, makes the already difficult case even more intricate. Nevertheless, the

• , the functionalization of the arms to include terminal β(1-3)-Gal reduces the occurrence of this event down to around 5%, see Table S6 in Supporting Information File 1. Terminal LeA and LeX motifs in plant N-glycans: To understand how an increased complexity on the arms would affect the dynamics of the

Polarity effects in 4-fluoro- and 4-(trifluoromethyl)prolines

• Vladimir Kubyshkin

Beilstein J. Org. Chem. 2020, 16, 1837–1852, doi:10.3762/bjoc.16.151

• . Nonetheless, it is barely conclusive to approach interaction of complex molecules with solvents using net dipole alone. For example, even for the relatively simple molecules like 1–4, the net dipole would not adequately represent neither the complexity of the interaction network within the molecule, nor

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• routes to afford molecular complexity from simple precursors, while concomitantly limiting the number of steps and waste generation. Following this general key objective, the landscape of organic synthesis has been clearly changed by the development of ecofriendly methodologies such as metal-catalyzed C

• motif, have also attracted significant scientific interest [103]. Such couplings allowed constructing molecular complexity from very simple arenes such as benzene, toluene or mesitylene. However, such transformations frequently required rather harsh reaction conditions as well as the addition of strong

Synthesis of Streptococcus pneumoniae serotype 9V oligosaccharide antigens

• Sharavathi G. Parameswarappa,
• Claney L. Pereira and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2020, 16, 1693–1699, doi:10.3762/bjoc.16.140

• escape the host immune response [1][7]. These polysaccharides of SP consist of repeating units (RU) that range from di- to heptasaccharides that may be branched and/or charged [8]. Modifications such as O-acetylation, phosphorylation, and sulfation further increase CPS complexity. Many bacterial

A dynamic combinatorial library for biomimetic recognition of dipeptides in water

• Florian Klepel and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2020, 16, 1588–1595, doi:10.3762/bjoc.16.131

• compounds could not be achieved due to the high complexity of the library and the structural similarity of its members. Hence ESI-TOF mass spectrometry data can be interpreted qualitatively but not quantitatively. A full reference sample is shown in Figure 1. Each chromatogram represents a single

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• ]. These systems are designed to achieve a generality of operation, and this comes with an increase in the cost and complexity of the instruments. Our on-demand approach targets the opposite end of the equipment design spectrum; it requires a low-cost systems designed to carry out only a few specific

• functions in a safe and robust manner. It also demands to be low-cost in order to have any potential for real-world applications. In other words, to achieve the set goals, innovation is needed to reduce the complexity/expense of (1) pumps; (2) reactors; (3) valves; (4) fittings, and (5) chemical containers

Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

• Carlos H. Escalante,
• Eder I. Martínez-Mora,
• Carlos Espinoza-Hicks,
• Alejandro A. Camacho-Dávila,
• Fernando R. Ramos-Morales,
• Francisco Delgado and
• Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

• with the complexity of its structures [11][19][20][21][22][23][24][25][26][27]. The intramolecular Heck arylation coupling reaction is among the most useful strategies for the construction of these compounds (Scheme 1) [11][21]. For example, isoindolo[2,1-a]indoles 6 have been prepared by the

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• , arylalkyl, and diaryl oxime radicals was also studied by EPR spectroscopy [53]. Radicals were generated under inert atmosphere directly in the EPR cavity by photolysis of the added di-tert-butyl peroxide (Scheme 1). The authors pointed out the complexity of the processes of iminoxyl radicals’ decomposition

A smart deoxyribozyme-based fluorescent sensor for in vitro detection of androgen receptor mRNA

• Ekaterina A. Bryushkova,
• Erik R. Gandalipov and
• Julia V. Nuzhina

Beilstein J. Org. Chem. 2020, 16, 1135–1141, doi:10.3762/bjoc.16.100

• types of compounds. It is most promising to develop simple and effective biosensors for the use in situations where traditional methods are not available due to their complexity and laboriousness. In this project, a novel smart deoxyribozyme-based fluorescent sensor for the detection of androgen

A simple and easy to perform synthetic route to functionalized thienyl bicyclo[3.2.1]octadienes

• Dragana Vuk,
• Irena Škorić,
• Valentina Milašinović,
• Krešimir Molčanov and
• Željko Marinić

Beilstein J. Org. Chem. 2020, 16, 1092–1099, doi:10.3762/bjoc.16.96

• numerous biologically active natural compounds (Figure 1) [4][5][6][7], their strenuous isolation procedures from plants, as well as their complicated multistage synthesis due to the complexity of their structure, encouraged us to develop a simple one-step synthetic procedure based on a photochemical

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

• complexity of the aforementioned macromolecules caused by PTM still constitutes a technical challenge. They can only be applied to small amounts of pure material, which is insufficient for extended biological investigations [4][6]. Hitherto, a variety of glycopeptides are used for medicinal applications, for

Diversity-oriented synthesis of 17-spirosteroids

• Benjamin Laroche,
• Thomas Bouvarel,
• Martin Louis-Sylvestre and
• Bastien Nay

Beilstein J. Org. Chem. 2020, 16, 880–887, doi:10.3762/bjoc.16.79

• their characteristic 3D geometry [68]. In particular, with 17-spirosteroids [69][70][71][72][73][74][75][76], the three dimensional complexity of the steroid CD-ring system is expected to be substantially affected. Results and Discussion The first goal of this work aimed at synthesizing spirocyclic