Formation of alkyne-bridged ferrocenophanes using ring-closing alkyne metathesis on 1,1’-diacetylenic ferrocenes

• Celine Bittner,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2019, 15, 2534–2543, doi:10.3762/bjoc.15.246

• ethyne [94]. Interestingly, a disorder of the iron position in the butynylferrocene 1a can be observed, obviously being responsible for the slightly longer Fe–Ct distances as compared to 1b. The main position Fe has an occupation of 74%. The disordered position Fe’ with an occupation of 26% is located

• between the centroid of C11 and the centroid of C1’ of the following ferrocene unit connected through the main position Fe resulting in a chain like structure of ferrocenes. An ORTEP drawing of this structure can be found in the Supporting Information File 1 (Figure S15). Because of this disorder the

• disorder on the iron position. Unfortunately, no single crystals for X-ray diffraction analysis could be obtained with such disorder being absent. For the catalytic RCAM (Scheme 1), the substrates 1a and 1b were dissolved in toluene at high dilution (4.5 mM), and the catalyst MoF6 (2 mol %) was added as a

Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

• Alessandro Iagatti,
• Baihao Shao,
• Alberto Credi,
• Barbara Ventura,
• Ivan Aprahamian and
• Mariangela Di Donato

Beilstein J. Org. Chem. 2019, 15, 2438–2446, doi:10.3762/bjoc.15.236

• the competition between the intramolecular hydrogen bond between the N–H and C=O groups in the Z-form and hydrogen bonds formed by these functional groups with solvent molecules. The conformational distortion and the increased conformational disorder arising from hydrogen bonding with the solvent can

• transfer nature, so that it can be stabilized in polar media where its lifetime slightly increases. In the protic solvent, however, where the molecule can adopt a partially twisted conformation, the increased conformational disorder most probably activates different non-radiative decay channels, shortening

Halide metathesis in overdrive: mechanochemical synthesis of a heterometallic group 1 allyl complex

• Ross F. Koby,
• Nicholas R. Rightmire,
• Nathan D. Schley,
• Timothy P. Hanusa and
• William W. Brennessel

Beilstein J. Org. Chem. 2019, 15, 1856–1863, doi:10.3762/bjoc.15.181

• ]∞ in low yield, which was crystallographically characterized as a coordination polymer that displays site disorder of the K+ and Cs+ ions. The entropic benefits of mixed Cs/K metal centers, but more importantly, the generation of multiple intermolecular K…CH3 and Cs…CH3 interactions in [CsKA'2

• depiction of a single chain is provided in Figure 1, and a partial packing diagram is given in Figure 2. The asymmetric unit contains three alkali metal cations and three substituted allyl anions, all in general positions. Each of the three metal sites is modeled as a site disorder of atoms types K and Cs

• . The structure suffers from twinning, disorder in the toluene, and weak diffraction, and therefore its structural details are degraded (a depiction of the coordination polymer is available in Supporting Information File 1). Fortunately, when [KA'] is dissolved in benzene and the solution evaporated, an

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• 2: a = 5.978(3), b = 29.005(11), c = 21.173(8) Å; α = 90°, β = 91.903(19)°, γ = 90°, V = 3669(3) Å3; DSS 4: a = 6.108(3), b = 29.049(17), c = 21.949(11) Å; α = 90°, β = 91.815 (12)°, γ = 90°, V = 3892(3) Å3). The molecules in both crystals evidenced some rotational disorder. Single crystals of

Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests

• Fangfang Pan,
• Mohadeseh Dashti,
• Michael R. Reynolds,
• Kari Rissanen,
• John F. Trant and
• Ngong Kodiah Beyeh

Beilstein J. Org. Chem. 2019, 15, 947–954, doi:10.3762/bjoc.15.91

• incredibly effective tool for observing privileged conformations and structures [15][16][17][18][19]. From the crystallographic information we can extract the polymorphism, high Z’-value, twining, and disorder that provide insight into the dynamics of prenucleation assembly, nucleation, and crystal growth

• the crystals form [26]. Twinning and disorder are generally seen as an undesirable complication in determining structures; however, the nature and extent of the disorder contains significant information regarding the dynamics and conformational sampling of the molecules [19][24][27]. Desiraju et al

• . employing substitutional disorder, achieved the co-crystallization of six components [28]. As for positional disorder, it generally indicates the same molecule or assembly can adopt more than one favourable conformation. From this perspective, disorder can be considered as a special case of a co-crystal or

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

• structures of 5 and 6 the co-ligands were found to be disordered over two positions. This disorder could be successfully modelled by using appropriate DFIX, DANG and AFIX instructions implemented in SHELXL. The site occupancy factors of the two orientations were initially refined, but were fixed at 0.65 and

Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• the research is devoted to diblock and triblock copolymers, whereas multiblock copolymer studies are still much less common [3][4][16][17][18]. Aside from more complicated synthesis and characterization of multiblock copolymers, for decades it was thought that any sequence disorder along polymer

A simple and effective preparation of quercetin pentamethyl ether from quercetin

• Jin Tatsuzaki,
• Tomohiko Ohwada,
• Yuko Otani,
• Reiko Inagi and
• Tsutomu Ishikawa

Beilstein J. Org. Chem. 2018, 14, 3112–3121, doi:10.3762/bjoc.14.291

• PMFs, among which quercetin pentamethyl ether (QPE, 3,5,7,3',4'-pentamethylquercetin; 3,5,7,3',4'-pentamethoxyflavone, 1, Figure 1) was the most potent [20]. Previous reports have shown that QPE (1) exhibits anticardiac hypertrophy [21], antidiabetic [22][23], antimetabolic disorder [13][24][25

Synthesis of pyrrolidine-based hamamelitannin analogues as quorum sensing inhibitors in Staphylococcus aureus

• Jakob Bouton,
• Kristof Van Hecke,
• Reuven Rasooly and
• Serge Van Calenbergh

Beilstein J. Org. Chem. 2018, 14, 2822–2828, doi:10.3762/bjoc.14.260

• . Structures of hamamelitannin (1), lead compound 2 and target compounds 3. Molecular X-ray structure of 3a, showing thermal displacement ellipsoids at the 50% probability level. Positional disorder of the chlorophenyl ring and the water solvent molecule are not shown. Proposed strategy for the synthesis of

Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers

• Christian Schütz and
• Martin Empting

Beilstein J. Org. Chem. 2018, 14, 2627–2645, doi:10.3762/bjoc.14.241

• positive. Recently, evidence has been provided that this ratio is reducing [19]. Nevertheless, with progression of age the majority of CF patients will become chronically infected with P. aeruginosa and this is still the major cause of death associated with this genetic disorder [20]. Importantly, it has

Synthesis of 3-aminocoumarin-N-benzylpyridinium conjugates with nanomolar inhibitory activity against acetylcholinesterase

• Nisachon Khunnawutmanotham,
• Cherdchai Laongthipparos,
• Patchreenart Saparpakorn,
• Nitirat Chimnoi and
• Supanna Techasakul

Beilstein J. Org. Chem. 2018, 14, 2545–2552, doi:10.3762/bjoc.14.231

• -related health issues, such as arthritis, heart disease, cancer, diabetes and Alzheimer’s disease, all of which can potentially decrease the quality of life. Dementia, commonly found among the elderly, can be caused by the Alzheimer’s disease (AD) – a progressive neurodegenerative disorder. The

Efficient catalytic alkyne metathesis with a fluoroalkoxy-supported ditungsten(III) complex

• Henrike Ehrhorn,
• Janin Schlösser,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2018, 14, 2425–2434, doi:10.3762/bjoc.14.220

• from [NaW2Cl7(THF)5] [86]. The 13C and 19F NMR spectra are also consistent with literature values. Crystals of W2F3 suitable for X-ray diffraction analysis were obtained upon cooling a saturated pentane solution to −40 °C. Unfortunately, the crystal structure suffers from severe disorder. Each tungsten

• atom is disordered over four positions, and additionally, the alkoxide ligands are also disordered (for more details, see Supporting Information File 1). Therefore, the crystal structure only confirms the connectivity and does not allow the discussion of bond lengths and angles. This disorder pattern

• connectivity of this molecule, and discussion of any bond length is not meaningful (for more details, see Supporting Information File 1). A similar crystal structure with the 2,4,6-trimethylbenzylidyne moiety at the tungsten atom, which does not exhibit disorder, has been reported previously [54]. Catalytic

Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[b]quinolizinium derivatives by Palladium-mediated cross-coupling reactions

• Siva Sankar Murthy Bandaru,
• Darinka Dzubiel,
• Heiko Ihmels,
• Mohebodin Karbasiyoun,
• Mohamed M. A. Mahmoud and
• Carola Schulzke

Beilstein J. Org. Chem. 2018, 14, 1871–1884, doi:10.3762/bjoc.14.161

• by crystallization from acetone and CHCl3/MeOH, respectively (Figure 2 and Figure S1, Supporting Information File 1). Derivative 2a crystallizes in the triclinic space group with two molecules in the unit cell. The crystals were twinned and the compound shows some considerable disorder. The chemical

Water-soluble SNS cationic palladium(II) complexes and their Suzuki–Miyaura cross-coupling reactions in aqueous medium

• Alphonse Fiebor,
• Richard Tia,
• Banothile C. E. Makhubela and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1859–1870, doi:10.3762/bjoc.14.160

• in literature [40]. The crystal structure of 17d also shows a static disorder of a CH2 carbon of one of the sec-butyl groups (C14). The atom site occupancy factors of the two positions of the CH2 carbon atom was refined to 0.571(11) and 0.429(11). This shows that the carbon atom has equal probability

Crystal structure of the inclusion complex of cholesterol in β-cyclodextrin and molecular dynamics studies

• Elias Christoforides,
• Andreas Papaioannou and
• Kostas Bethanis

Beilstein J. Org. Chem. 2018, 14, 838–848, doi:10.3762/bjoc.14.69

• SHELXL. H-atoms belonging to the disorder water molecules were not placed during refinement. Uiso(H) values were assigned in the range 1.2–1.5 times Ueq of the parent atom. In order to maintain a high (>6.7) data/parameters ratio, anisotropic thermal parameters were imposed only to O2, O3 and O6 atoms of

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• silicon atom, two phenyl rings can be introduced on the silicon-bridged structure providing bulkiness and rigidity to the donor. Intermolecular interactions are thus efficiently prevented and the conformation disorder drastically reduced. When used as electron donor in T1, a ΔEST of 0.14 eV was determined

What contributes to an effective mannose recognition domain?

• Christoph P. Sager,
• Deniz Eriş,
• Martin Smieško,
• Rachel Hevey and
• Beat Ernst

Beilstein J. Org. Chem. 2017, 13, 2584–2595, doi:10.3762/bjoc.13.255

• carbohydrate-based drugs. One such example of a therapeutic application can be found in a recent novel approach to treating anti-myelin-associated glycoprotein (anti-MAG) neuropathy, a rare, disabling autoimmune disorder. The use of a multivalent glycopolymer mimicking the natural HNK-1 epitope proved to be a

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

• observed by NMR spectroscopy in DMSO solution (≈10:7). Interestingly, for 15a, the major conformer corresponds to a rotameric state with a screened N1 atom, but in the major conformer of 15b, the N2 atom of the heterocycle is screened. Notably, similar structural disorder was previously observed in the

• ) Fragment of the 2D 15N-HMBC spectrum of 15a-15N2. The 1H-15N cross-peaks between the adamantane protons and 15N-labelled atoms are shown. ORTEP diagrams of the X-ray structures of compounds 15a-15N2 (a) and 15b-15N2 (b). For clarity, the H atoms are omitted. The observed disorder of the adamantane fragment

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

• disorder of the peptide body, including the side chain conformations; in contrast, CD represents only the backbone. The diffusion data (Figure 6) indicated that the hexaproline peptides 8a–c are rather rigid, the trilysine peptides 9a–c are somewhat more flexible, and the hexalysine peptides 10a–c are

• characterized by remarkable molecular disorder. In all cases, the C-terminal esterification reduced the level of disorder, although, the effect is hardly distinguishable from experimental error values. Overall, these results demonstrate that the side-chain disorder may play a more significant role in the

Homologated amino acids with three vicinal fluorines positioned along the backbone: development of a stereoselective synthesis

• Raju Cheerlavancha,
• Ahmed Ahmed,
• Yun Cheuk Leung,
• Aggie Lawer,
• Qing-Quan Liu,
• Marina Cagnes,
• Hee-Chan Jang,
• Xiang-Guo Hu and
• Luke Hunter

Beilstein J. Org. Chem. 2017, 13, 2316–2325, doi:10.3762/bjoc.13.228

• ; Introduction The incorporation of unnatural amino acids into a peptide structure can potentially reduce conformational disorder and hence improve the binding affinity of the peptide for its biological target. For example, conformationally rigid amino acids such as 1 (Figure 1) have been shown to dramatically

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• pharmaceutical ingredients. The following section will describe a few of such efforts. In 2013, Witt et al. reported a scalable process for the synthesis of GSK3B inhibitor AZD8926, 103 [99]. The drug is therapeutically useful for the treatment of CNS disorder viz. Alzheimer’s disease (AD), Schizophrenia and

Molecular recognition of N-acetyltryptophan enantiomers by β-cyclodextrin

• Spyros D. Chatziefthimiou,
• Mario Inclán,
• Petros Giastas,
• Athanasios Papakyriakou,
• Konstantina Yannakopoulou and
• Irene M. Mavridis

Beilstein J. Org. Chem. 2017, 13, 1572–1582, doi:10.3762/bjoc.13.157

• expected to have restricted mobility and limited disorder. Indicative of the interest and possible applications of the CD use in chiral selectivity/discrimination of tryptophan are studies in aqueous solution [21], in electrochemistry for sensor development [17][22][23], as components of solid phases in

• guest molecules of L-NAcTrp are enclosed in a head-to-head fashion (host:guest ratio, 1:1). The pair of L-NAcTrp molecules inside the dimer are found in orientational disorder, i.e., the guest exhibits a major orientation, molecules C and D (occupancy 65%), and a co-existing minor orientation (molecules

• 2.73 Å and 2.75 Å for A and B, respectively, 2.78 Å in hydrated β-CD) and (ii) intermolecularly, the O-3nA and O-(8−n)B atoms of monomers A and B, respectively (range of distances 2.7–2.8 Å, Supporting Information File 1, Table S2). At the primary side, only β-CD molecule B exhibits disorder of the C

Glycoscience@Synchrotron: Synchrotron radiation applied to structural glycoscience

• Serge Pérez and
• Daniele de Sanctis

Beilstein J. Org. Chem. 2017, 13, 1145–1167, doi:10.3762/bjoc.13.114

• crystallographic analysis. This is even more pronounced for compounds having molecular weights ranging from 1000 to 5000 Da. Among the reasons, there is the difficulty to produce sufficient amount of material or the intrinsic occurrence of molecular disorder in solution, where several forms coexists (linear, five

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97

• treatment of bipolar disorder and schizophrenia [10]. The process involves four reaction steps, one inline extraction, and a filtration step. The reaction is shown in Scheme 1. Initially, a Buchwald–Hartwig reaction is carried out between aryl iodide and aminothiazole. Pd2dba3 was used as a catalyst and

Inclusion complexes of β-cyclodextrin with tricyclic drugs: an X-ray diffraction, NMR and molecular dynamics study

• Franca Castiglione,
• Fabio Ganazzoli,
• Luciana Malpezzi,
• Andrea Mele,
• Walter Panzeri and
• Giuseppina Raffaini

Beilstein J. Org. Chem. 2017, 13, 714–719, doi:10.3762/bjoc.13.70

• any disorder: this finding is largely predictable for the rigid tricyclic moiety of 1 but it is remarkable in 2. Indeed, literature data on isolated amitriptyline point out that the fused ring system of 2 shows conformational transitions [10], especially those involving the torsion about the C9–C10

• single bond. The lack of disorder in the C9–C10 segment suggests that complexation constrains 2 in a single conformation in the solid state. The MD simulations led to the formation of a 1:1 inclusion complex of β-CD with molecules 1 and 2 both in vacuo and in explicit water. In both cases, the complex