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

• assist in refining our understanding of bacterial terpenoid biosynthesis. Examples of bioactive terpenoids. Repetitive electrophilic and nucleophilic functionalities in terpene and type II PKS-derived polyketide biosynthesis. a) Schematic representation. b) Type II PKS-derived polyketide biosynthesis. c

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

• /H2O, 1:2, v/v, middle right), 12 (DMSO, bottom left), and 14 (DMSO/H2O, 9:1, v/v, bottom right). ORTEP representation of the molecular structure of compound 12 (trans configuration) obtained from X-ray diffraction data. Crystal packing of compound 12 (trans configuration) in DMSO. Crystal packing of

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

• considered to translate these geometrical changes to changes in properties such as guest binding affinity and selectivity. Schematic representation of a photoresponsive cage with ligands based on overcrowded alkenes. Aromatic region of stacked 1H NMR spectra (in CD3CN) of stable Z-1 and cage complex Pd2

A toolbox of molecular photoswitches to modulate the CXCR3 chemokine receptor with light

• Xavier Gómez-Santacana,
• Sabrina M. de Munnik,
• Tamara A. M. Mocking,
• Niels J. Hauwert,
• Shanliang Sun,
• Prashanna Vijayachandran,
• Iwan J. P. de Esch,
• Henry F. Vischer,
• Maikel Wijtmans and
• Rob Leurs

Beilstein J. Org. Chem. 2019, 15, 2509–2523, doi:10.3762/bjoc.15.244

• photopharmacological studies on the dynamic signaling of the chemokine receptor CXCR3. Design of the CXCR3 efficacy photowitchable ligands. A,B) Schematic representation of a GPCR photochromic ligand that photoisomerizes and thereby photoswitches (A) binding affinity and/or (B) functional efficacy. Red represents the

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• synthase CotB2wt·Mg2+3·F-Dola in the closed, active conformation (PDB-ID 6GGI; [37]). (A) The two monomers of CotB2 are shown in cartoon representation with the α-helices drawn as cylinders and colored in light brown. One monomer of CotB2 is shown in gray surface representation. The location of the

• closed (light-brown, CotB2wt·Mg2+3·F-Dola) conformation. The overall fold of CotB2wt·Mg2+B·GGSDP (PDB-ID 5GUE; [36]) is more similar to CotB2wt (PDB-ID 4OMG; [38]) than to CotB2wt·Mg2+3·F-Dola (PDB-ID 6GGI; [37]). The salt bridge between D111 and R294, in stick representation, is shown by red, dashed

• ) Streptomyces xinghaiensis. (A) The inner surface of the active site is shown in gray. The bound F-Dola reaction intermediate is shown in magenta with the fluorine atom colored in light blue. Aromatic residues are shown in black stick representation (B) View of panel A rotated by 90°. (C) View from the top into

Perspective isomorphs – a new classification of molecular structures based on artistic and chemical concepts

• Jannis Neumann,
• Ansgar Schnurr and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2019, 15, 2319–2326, doi:10.3762/bjoc.15.224

• isomorphs and its discussions herein will extend current models and stimulate the discourse about the nature of atoms and molecules and especially their models. Keywords: art and science; nomenclature; perspective; representation in chemistry; structure; Introduction Up to now, epistemological concepts of

• visually based cognition from the renaissance to modern age derive predominately from the human act of observing. The visually captured world is perceived as a spatially arranged scene in perspective dependency to the viewer. For pictorial representation, only the visible is relevant. Due to the size of

• possibility of specific orientation and space-depended interactions, such as hydrogen-bonds, etc., which is of utmost importance for instance in any biological process [15]. Proposal of perspective isomorphs When applying the principle of the central perspective to the view on molecules, their representation

Fluorescent phosphorus dendrimers excited by two photons: synthesis, two-photon absorption properties and biological uses

• Anne-Marie Caminade,
• Artem Zibarov,
• Eduardo Cueto Diaz,
• Aurélien Hameau,
• Maxime Klausen,
• Kathleen Moineau-Chane Ching,
• Jean-Pierre Majoral,
• Jean-Baptiste Verlhac,
• Olivier Mongin and
• Mireille Blanchard-Desce

Beilstein J. Org. Chem. 2019, 15, 2287–2303, doi:10.3762/bjoc.15.221

•  2, showing in particular the generations, i.e., the number of layers, both for the full structure, and for a linear representation of the same dendrimer, which will be mainly used in this review. Many different types of fluorescent dendrimers (with hundreds of publications), having one or several

An overview of the cycloaddition chemistry of fulvenes and emerging applications

• Ellen Swan,
• Kirsten Platts and
• Anton Blencowe

Beilstein J. Org. Chem. 2019, 15, 2113–2132, doi:10.3762/bjoc.15.209

• throughout this article [34]. Generic structures of commonly referenced heteropentafulvenes, named according to the heteroatom substitution: oxafulvene, azafulvene, phosphafulvene, thiafulvene and silafulvene. A representation of HOMO–LUMO orbitals of pentafulvene and the influence of EWG and EDG

α-Photooxygenation of chiral aldehydes with singlet oxygen

• Dominika J. Walaszek,
• Magdalena Jawiczuk,
• Jakub Durka,
• Olga Drapała and
• Dorota Gryko

Beilstein J. Org. Chem. 2019, 15, 2076–2084, doi:10.3762/bjoc.15.205

• ). Stereoselective α-photooxygenation of 3,4-diphenylbutanal (1) with 1O2. Schematic representation of the in situ methodology and preferred conformation of diols with Mo2 core. Asymmetric synthesis of 3,4-diphenylbutane-1,2-diol. Stereoselectivity of α-photooxygenation reaction of 3,4-diphenylbutanal (1

Archangelolide: A sesquiterpene lactone with immunobiological potential from Laserpitium archangelica

• Silvie Rimpelová,
• Michal Jurášek,
• Lucie Peterková,
• Jiří Bejček,
• Vojtěch Spiwok,
• Miloš Majdl,
• Michal Jirásko,
• Miloš Buděšínský,
• Juraj Harmatha,
• Eva Kmoníčková,
• Pavel Drašar and
• Tomáš Ruml

Beilstein J. Org. Chem. 2019, 15, 1933–1944, doi:10.3762/bjoc.15.189

• -specific dye from [20] (10 min; image C) or pDNA coding mCherry-ER (image G). D, H) merged images. Cartoon representation of sarco/endoplasmic reticulum Ca2+ ATPase binding pocket with A, C) archangelolide (1) or B, D) trilobolide (2) after molecular dynamic simulations. Depicted are also amino acid

• residues in a range of 5 Å from the respective ligand. The images were created using VMD software, version 1.9.2. Molecular surface representation of sarco/endoplasmic reticulum Ca2+ ATPase binding pocket with A) archangelolide (1) and B) trilobolide (2) after molecular dynamic simulations. SURF function

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

• of theory. (a) Top view and (b) side view of H4·G3, and (c) top view and (d) side view of H5·G3. Schematic representation of the acid–base controlled complexation process and partial 1H NMR spectra (300 MHz, CD2Cl2, 298 K) of (a) free H2, (b) to the solution of complex H2·G4 were added 2.2 equiv of

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

• orientation of the narrow rim hydrogen bonds is CCW; (B) structure with “open” narrow rim; and (C) energy difference between these two configurations at the M062X/6-311++G(d,p)//M062X/6-31G(d,p) level of theory. Schematic representation of β-CD–nH2O complexes (where n = 1–12) with water molecules/clusters

A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• ) SEM image and (c) TEM image showing the nanoranged particle distribution of the macrocycle. Dependence of the yield of compound 4a on the reaction time using BATA-MC. Yields of product 4a at different catalyst loading. X-ray single crystal structure of 4d (CCDC 1898008). Representation of BATA-MC

Host–guest interactions between p-sulfonatocalix[4]arene and p-sulfonatothiacalix[4]arene and group IA, IIA and f-block metal cations: a DFT/SMD study

• Valya K. Nikolova,
• Cristina V. Kirkova,
• Silvia E. Angelova and
• Todor M. Dudev

Beilstein J. Org. Chem. 2019, 15, 1321–1330, doi:10.3762/bjoc.15.131

• ). Schematic representation of the structures of p-sulfonatocalix[4]arene (C[4]A) and p-sulfonatothiacalix[4]arene (TC[4]A). BSSE-corrected Gibbs free energies (in kcal mol−1) in the gas phase (ΔG1) and in water (ΔG78) for the [C[4]A–M](4−n)− and [TC[4]A–M](4−n)− (n = 1–3) complex formation reactions, C[4]A

Understanding the unexpected effect of frequency on the kinetics of a covalent reaction under ball-milling conditions

• Ana M. Belenguer,
• Adam A. L. Michalchuk,
• Giulio I. Lampronti and
• Jeremy K. M. Sanders

Beilstein J. Org. Chem. 2019, 15, 1226–1235, doi:10.3762/bjoc.15.120

• polymorph of the heterodimer, form A and form B respectively, crystallizes. The details of form A (CCDC code FUQLIM01) and form B (CCDC code FUQLIM) have been previously reported. Schematic representation of a solid + solid mechanochemical reaction. Subscript denote macroscopic (m) and comminuted (m

Towards the preparation of synthetic outer membrane vesicle models with micromolar affinity to wheat germ agglutinin using a dialkyl thioglycoside

• Dimitri Fayolle,
• Nathalie Berthet,
• Bastien Doumeche,
• Olivier Renaudet,
• Peter Strazewski and
• Michele Fiore

Beilstein J. Org. Chem. 2019, 15, 937–946, doi:10.3762/bjoc.15.90

• for all micrographs in this figure. A simplified (and not in scale) representation of the ELLA assay, to study the interaction between GVs or micelles of compound 8 or 5 and WGA. OPD: O-phenylenediamine dihydrochloride; PAA: poly[N-(2-hydroxyethyl)acrylamide]. Inhibition curves for the binding of WGA

• the docked compound are in white stick representation. A) Representative poses obtained for 5C2 (yellow sticks) and 5C4 (orange sticks) at the B1C2 primary site superimposed with co-crystallized GlcNAc (white sticks). B) Representative poses of 8C4 (orange and yellow sticks) obtained at the D2A1 and

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• of unsymmetrically substituted azobenzene [58]. a) Schematic representation for the construction of a [2]rotaxane. b) Chiu’s ball-milling approach for the synthesis of [2]rotaxanes. Mechanochemical synthesis of the smallest [2]rotaxane. Solvent-free mechanochemical synthesis of pillar[5]arene

Synthesis of a novel category of pseudo-peptides using an Ugi three-component reaction of levulinic acid as bifunctional substrate, amines, and amino acid-based isocyanides

• Maryam Khalesi,
• Azim Ziyaei Halimehjani and
• Jürgen Martens

Beilstein J. Org. Chem. 2019, 15, 852–857, doi:10.3762/bjoc.15.82

• multiplet at 4.40–5.00 ppm for the CH group in the stereogenic center. Carbons of the amide and ester moieties were observed around 170–177 ppm in 13C NMR spectra. In addition, the structure of compound (R*,S*)-4a was confirmed by single crystal X-ray diffraction and an ORTEP representation is shown in

• . cIsolated yield of one of the diastereomers as pure stereoisomer after several recrystallization steps. ORTEP representation of compound (R*,S*)-4a with thermal ellipsoids at 50% probability. Opposite enantiomer is omitted for clarity. The atom numbering does not follow IUPAC nomenclature. Synthesis of

Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands

• Jennifer Klose,
• Tobias Severin,
• Peter Hahn,
• Alexander Jeremies,
• Jens Bergmann,
• Daniel Fuhrmann,
• Jan Griebel,
• Bernd Abel and
• Berthold Kersting

Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81

• π–π stacking occurs in this structure. [Cd2L(μ-azo-CO2Me)]BPh4.MeCN (8·MeCN): The crystal structure determination of 8·MeCN confirms that azo-CO2Me is also attached in the bridging mode. Figure 9 shows an ORTEP representation of the structure of the [Cd2L(μ-azo-CO2Me)]+ cation in 8. The [Cd2L]2

• blue, O red, S yellow, metals flesh (Zn, Cd) or green (Ni)). Space filling representation of the packing of two symmetry-related [Zn2L(μ-azo-NMe2)]+ cations in crystals of 5·1.5MeCN. The ClO4− anions and solvate molecules are omitted for clarity. Structure of the [Cd2L(μ-azo-NMe2)]+ cation in crystals

• of [Cd2L(μ-azo-NMe2)]ClO4·0.5MeOH (6·0.5MeOH). Only one orientation of the disordered azobenzene carboxylato co-ligand is displayed. Hydrogen atoms omitted for clarity. Thermal ellipsoids are drawn at the 50% probability level. Space filling representation of the packing of four [Cd2L(μ-azo-NMe2

Synthesis of acylglycerol derivatives by mechanochemistry

• Karen J. Ardila-Fierro,
• Andrij Pich,
• Marc Spehr,
• José G. Hernández and
• Carsten Bolm

Beilstein J. Org. Chem. 2019, 15, 811–817, doi:10.3762/bjoc.15.78

• milling. In order to improve the yield, we carried out the activation of the Co(II) complex (S,S)-cat by milling under a balloon pressure of dioxygen. Now, the yield of 4a was boosted up to 84% yield (for a representation of the set up used and experimental details, see Scheme 3c and Supporting

Homo- and hetero-difunctionalized β-cyclodextrins: Short direct synthesis in gram scale and analysis of regiochemistry

• Gábor Benkovics,
• Mihály Bálint,
• Éva Fenyvesi,
• Erzsébet Varga,
• Szabolcs Béni,
• Konstantina Yannakopoulou and
• Milo Malanga

Beilstein J. Org. Chem. 2019, 15, 710–720, doi:10.3762/bjoc.15.66

• favored. • The monotosylation of 6-monoazido-β-CD (both in pyridine and Cu(II)-mediated in aqueous solution) is a primary-side process that leads to the theoretical three couples of pseudoenantiomers. Schematic representation of β-CD with glucopyranose atom numbering and with alphabetic labeling of the

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

• °C; f) 70 °C. Purple dots in spectra indicate the newly emergent peaks upon heating. Chemical structures of 3a–e and 5a–e, and the cartoon representation of LCST behavior. Synthetic routes and yields of 3a–e and 5a–e. Supporting Information Supporting Information File 44: Experimental

Computational characterization of enzyme-bound thiamin diphosphate reveals a surprisingly stable tricyclic state: implications for catalysis

• Ferran Planas,
• Michael J. McLeish and
• Fahmi Himo

Beilstein J. Org. Chem. 2019, 15, 145–159, doi:10.3762/bjoc.15.15

• energy corrections, and solvation energies were calculated using the implicit solvent method SMD [67] with a dielectric constant ε = 4. A) 2D representation of ThDP (blue) and the residues included in the active site models, and B) optimized structure of model B with an empty active site. Asterisks mark

Adhesion, forces and the stability of interfaces

• Robin Guttmann,
• Johannes Hoja,
• Christoph Lechner,
• Reinhard J. Maurer and
• Alexander F. Sax

Beilstein J. Org. Chem. 2019, 15, 106–129, doi:10.3762/bjoc.15.12

• principle which plays the dominant role in chemistry” [17]. Exchange repulsion can be described by a repulsive potential–energy function with exponentially decaying dependence on the interatomic distance [18][19]. Its representation by a potential–energy function is similar to the use of local, repulsive

The influence of the cationic carbenes on the initiation kinetics of ruthenium-based metathesis catalysts; a DFT study

• Magdalena Jawiczuk,
• Angelika Janaszkiewicz and
• Bartosz Trzaskowski

Beilstein J. Org. Chem. 2018, 14, 2872–2880, doi:10.3762/bjoc.14.266

• 1, 2 or 3. Schematic representation of carbene dimerization and atom numbering scheme used throughout this work. Dissociative mechanism of initiation for Grubbs-like 1–3-GrI and M1 indenylidene type complexes 1–3-Ind; L = carbene 1, 2 or 3. Dissociative mechanism of initiation of 2nd generation