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

• scaling up can be achieved by numbering up. One of the most used photomicroreactors are capillaries wrapped around a light source. Such microcapillaries can be scaled up by connecting them either in parallel or in series (Figure 3a and Figure 3b). In a previous study, five polymer-based microcapillaries

• -benzophenone (DMBP) was studied. A single multisyringe pump was used to supply the reactants to the photomicroreactors. This kind of scaling up is called external numbering up since each reactor is fed directly by the pump. This numbering-up strategy allowed to run ten parallel microreactors at the same time

• . This microreactor setup used 30% less energy than the batch reactor, without the requirement of cooling [31]. The PSTY in this paper was calculated based on the same reaction being performed at the same time in ten parallel reactors (Table 1, entry 1). The reactions that are presented in Table 1 are

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• transition dipole moment with respect to the DNA chiral axis [50]. A positive sign observed for 3a suggests that the long axis of the NDI chromophore is perpendicular to the longitudinal axis of the base pairs (red arrow in Figure 8, for 3a), while a negative one observed for 3b suggests a parallel

• predominantly a parallel orientation for all dyes as shown in Figure 8 for the DNA–3b complex. The absence of any measurable ICD signal for poly(A)-poly(U) (ds-RNA) (Supporting Information File 1, Figure S26) supports the intercalation of all NDI chromophores at approximately 45° with respect to the base pair

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

• experimental data that the basicity reduction from substituents that are parallel and perpendicular to the pyrrolidine ring are different. There are examples showing that the C–F or C–CF3 fragment in plane with the ammonium dipole reduces the basicity by about ΔpKa ≈ 2.2 [72][73]. The same value was obtained

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

• previous functionalization, thus considerably reduce waste generation and a number of synthetic steps. In parallel, transformations involving photoredox catalysis promote radical reactions in the absence of radical initiators. They are conducted under particularly mild conditions while using the visible

• previously inaccessible molecules could be expected. C–H activation reactions, generally do not change the oxidation state of the metal and are favored in the case of aromatic or vinylic substrates but are clearly more challenging when using aliphatic precursors [21][22][23][24][25][26][27][28]. In parallel

• concerned the development of “classical” C–H activation reactions, while a photoredox cycle was implemented to reoxidize the metal catalyst, thus obviating the need for a stoichiometric amount of metal-based oxidants, such as silver or copper salts. In parallel, dual synergistic catalysis has emerged. In

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• with radioactively labeled substrates, the use of fluorescently labeled probes offers several advantages, including the continuous monitoring of the transport and a better time resolution. For reasons of comparison, the α-configured ᴅ-mannose probe MPC-3 was synthesized in parallel. The

Synthesis of the tetrasaccharide repeating unit of the O-specific polysaccharide of Azospirillum doebereinerae type strain GSF71^T using linear and one-pot iterative glycosylations

• Arin Gucchait,
• Pradip Shit and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2020, 16, 1700–1705, doi:10.3762/bjoc.16.141

• obtained following the sequential glycosylation strategy (Scheme 2). It is noteworthy that in parallel to the sequential glycosylation strategy, the desired tetrasaccharide derivative 7 could be achieved in comparably good yield following the one-pot protocol involving the three iterative glycosylations

Models of necessity

• Timothy Clark and
• Martin G. Hicks

Beilstein J. Org. Chem. 2020, 16, 1649–1661, doi:10.3762/bjoc.16.137

• could exist in parallel to the bonding models used and discussed in teaching and research. This, however, would waste a unique opportunity to rationalize chemical thinking and communication and to establish the concept of models as the language of chemistry. The major requirements of a chemical ontology

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

• the parallel dimer of CHC (p(CHC)2), which binds two molecules of the neurotransmitter N-acetylneuraminic acid (NANA) in a cooperative fashion (K1 = 143, K2 = 5.1 × 103 M−1). Recently we rationalized that since our peptide building blocks consist of the same binding motifs as binding proteins (amines

• tripeptide dimers can be found after equilibration. We note that this simple mixture of 4 peptides contains 10 different homo- and heterodimer combinations. In addition, since our building blocks are asymmetrical, parallel and antiparallel constitutional isomers are formed (Scheme 1b), which raises the total

• a) p(CFC)2 to YY b) p(CFC)2 to FF c) a(CFC)2 to YY d) a(CFC)2 to FF. Job plots derived from the continuously varied NMR measurements of a) p(CFC)2 to YY b) p(CFC)2 to FF c) a(CFC)2 to YY d) a(CFC)2 to FF. a) Building blocks included in this study. b) Antiparallel and parallel constitutional isomers

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

• 8b/7c and 8c/7c (Figure 4a,b and Supporting Information File 1, Appendix 6). All the observable π···π interactions were parallel-displaced (offset) π-stacking, and the distance values were within the range of the known values, whether determined from X-ray structures or calculated values (3.2–4.0 Å

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• crystals were a typical druse setup. Type 2 were well-formed, nonisotropic crystals with two parallel planes in varying sizes (0.3 × 0.4 × 1 mm). The thermogravimetric analysis and differential scanning calorimetry (TGA-DSC) of F-1 was conducted to examine its thermal properties. The TGA curve of the bulk

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

• -isomers of compounds 3–7. Molecular structure of compound trans-6. Displacement ellipsoids are drawn for the probability of 30% and hydrogen atoms are shown as spheres of arbitrary radii. Crystal packing of trans-6. (a) Chain parallel to [100] and (b) chain parallel to [010]. 1H NMR spectra (CDCl3) of

Synthesis and anticancer activity of bis(2-arylimidazo[1,2-a]pyridin-3-yl) selenides and diselenides: the copper-catalyzed tandem C–H selenation of 2-arylimidazo[1,2-a]pyridine with selenium

• Mio Matsumura,
• Tsutomu Takahashi,
• Hikari Yamauchi,
• Shunsuke Sakuma,
• Yukako Hayashi,
• Tadashi Hyodo,
• Tohru Obata,
• Kentaro Yamaguchi,
• Yasuyuki Fujiwara and
• Shuji Yasuike

Beilstein J. Org. Chem. 2020, 16, 1075–1083, doi:10.3762/bjoc.16.94

• phenyl rings that face each other were almost parallel (mean-interplanar angles: Ph(A)–ImdazoPy(B): 4.59° and Ph(B)–ImdazoPy(A): 4.64°, Figure S2, Supporting Information File 1), and 2a exhibited intramolecular π–π interactions over the whole molecule. The monoselenide 3a exhibited a C1A–Se–C2A angle of

Accelerating fragment-based library generation by coupling high-performance photoreactors with benchtop analysis

• Quentin Lefebvre,
• Christophe Salomé and
• Thomas C. Fessard

Beilstein J. Org. Chem. 2020, 16, 982–988, doi:10.3762/bjoc.16.87

• temperatures and a mild base. Inspired by work at Merck on chemical informers, we decided to exploit our library of spirocyclic amines and strained scaffolds to generate a focused list of potential products [13]. We wanted to perform parallel reactions on small scale to gain further knowledge on the reactivity

• were slightly altered: a smaller excess of amine was used, and dimethyl sulfoxide (DMSO) was chosen as solvent instead of dimethylformamide (DMF) or dimethylacetamide (DMA) to improve work-up and purification. The workflow was devised to ensure maximal productivity, using parallel experimentation

• enabled rapid and precise assessment of the success of each parallel reaction. As seen in Figure 2, a single TLC plate reporting five different reactions could be analyzed in five minutes, and the identity of the major product confirmed by mass. Finally, after work-up and automated purification, a

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

• Zeguo Fang,
• Nawaf Al-Maharik,
• Peer Kirsch,
• Matthias Bremer,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2020, 16, 674–680, doi:10.3762/bjoc.16.65

• the requirements for different LCD technologies. For the traditional twisted nematic (TN) LCD technology, devices require liquid crystals with display positive dielectric anisotropy by which the molecular dipole moment is oriented parallel to the long axis of the molecule, while for the current

• dielectric anisotropy by introducing the C–F bond or the dipole of a CF2 group either parallel or perpendicular to the long molecular axis. For example, in the area of negative liquid crystalline materials, Kirsch et al. have reported the synthesis of bicyclohexane and bis(cyclohexyl)ethane liquid crystals

Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas

• Zhenghui Liu,
• Peng Wang,
• Zhenzhong Yan,
• Suqing Chen,
• Dongkun Yu,
• Xinhui Zhao and
• Tiancheng Mu

Beilstein J. Org. Chem. 2020, 16, 645–656, doi:10.3762/bjoc.16.61

• yield increased with increasing temperature. At low temperature the reaction did not proceed at all, however, at 90 °C or higher, a nearly quantitative yield of benzaldehyde was obtained (Figure 1d). Next, parallel experiments were conducted at three selected temperatures (80 °C, 90 °C, and 100 °C) to

• with CO and H2 to afford benzaldehyde. a) Effects of the tested bases; b) effects of base amount; c) effects of tested solvents; d) temperature screen; e) yields at different times for reactions performed at 80, 90 and 100 °C (every point represents an average result of three parallel experiments

Design and synthesis of diazine-based panobinostat analogues for HDAC8 inhibition

• Sivaraman Balasubramaniam,
• Sajith Vijayan,
• Liam V. Goldman,
• Xavier A. May,
• Kyra Dodson,
• Sweta Adhikari,
• Fatima Rivas,
• Davita L. Watkins and
• Shana V. Stoddard

Beilstein J. Org. Chem. 2020, 16, 628–637, doi:10.3762/bjoc.16.59

• of this class of inhibitors in HDACs [31][32][33][34]. Again, our work here extends the investigation focusing on HDAC8 due to the need for novel neuroblastoma therapeutics. Each compound was also shown to have two parallel-displaced π–π interactions, one with Phe-152 and the other with Phe-208. The

• interaction with the Zn2+ ion. TOI3-rev, like that of TOI1, TOI2, and TOI4 produces two parallel-displaced π–π interactions with Phe-152 and Phe-208 (Figure 2). The pyrimidine ring of TOI3-rev also lays planar in the gorge similar to the pyrazine and pyrimidine rings of TOI1 and TOI2. The indole ring of TOI3

• reaction mixture under heating conditions. In parallel, similar reaction conditions were used for compound 3 and the final coupled product 18 was obtained in 71% yield. The product was confirmed by the expected chemical shift at δ 6.50 and 7.54 ppm with a J value of 15 Hz for compound 16 (Supporting

Opening up connectivity between documents, structures and bioactivity

• Christopher Southan

Beilstein J. Org. Chem. 2020, 16, 596–606, doi:10.3762/bjoc.16.54

• . Although their expert-curated numbers are lower (i.e., ≈2 million compounds against ≈3700 human proteins), these open sources have the great advantage of being merged within PubChem. Parallel efforts have focused on the extraction of document-to-compound (D-C-only) connectivity. In the absence of molecular

• seems that way). The following is a selection: 1.) PubChem presents users with the complexity of parallel systems of D-C connectivity [28]. For medical subject headings (MeSH) the publication links are biased towards common name matches in many papers (e.g., the MeSH category for chemicals and drugs

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• helped to understand the function and formation H and J-aggregates [46][47][48][49] being aligned parallel or in series, respectively. The capability of cyanines to form J-aggregates exhibiting a huge bathochromic shift, which was reported for the first time by Scheibe [50] and Jelley in 1937 [51

Oligomeric ricinoleic acid preparation promoted by an efficient and recoverable Brønsted acidic ionic liquid

• Fei You,
• Xing He,
• Song Gao,
• Hong-Ru Li and
• Liang-Nian He

Beilstein J. Org. Chem. 2020, 16, 351–361, doi:10.3762/bjoc.16.34

• used as lubricant for metal cutting oils due to its appropriate viscosity, good adsorptivity and film formation ability on metal surfaces. Furthermore, the biodegradability of these estolides in the environment makes them attractive as green products. In parallel with the increasing demand for high

Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations

• Rafia Siddiqui and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26

• 59 are obtained by the reduction of the Co(II) catalyst 53 by radical 58. In order to form the desired cyclized product, rearomatization of 59 takes place, and protonation of 55 assists the regeneration of 56, with parallel hydrogen release, as shown in Figure 10. C–H cyclization Synthesis of

Reversible photoswitching of the DNA-binding properties of styrylquinolizinium derivatives through photochromic [2 + 2] cycloaddition and cycloreversion

• Sarah Kölsch,
• Heiko Ihmels,
• Jochen Mattay,
• Norbert Sewald and
• Brian O. Patrick

Beilstein J. Org. Chem. 2020, 16, 111–124, doi:10.3762/bjoc.16.13

• the differential absorption of linearly polarized light, which was polarized parallel and perpendicular to a reference axis, respectively, thus indicating the orientation of the transition moment of the chromophores relative to the electric field vector of the light [75]. The LD spectrum of DNA-bound

Synthesis of C-glycosyl phosphonate derivatives of 4-amino-4-deoxy-α-ʟ-arabinose

• Lukáš Kerner and
• Paul Kosma

Beilstein J. Org. Chem. 2020, 16, 9–14, doi:10.3762/bjoc.16.2

• in more detail using phosphodiester-linked derivatives in both anomeric configurations and containing short lipid appendages in order to define the minimum structural requirements for Ara4N glycosyltransferase substrates [9]. In parallel, we have started to develop C-phosphonate analogues as these

Extension of the 5-alkynyluridine side chain via C–C-bond formation in modified organometallic nucleosides using the Nicholas reaction

• Renata Kaczmarek,
• Dariusz Korczyński,
• James R. Green and
• Roman Dembinski

Beilstein J. Org. Chem. 2020, 16, 1–8, doi:10.3762/bjoc.16.1

• ]. In parallel, bioorganometallic chemistry provides new tools to influence biological interactions [16][17][18][19][20][21][22][23][24]. Cobalt possesses a diverse array of properties that can be manipulated to yield promising drug candidates [25]. The antiproliferative properties [26], as well as

Chemical synthesis of tripeptide thioesters for the biotechnological incorporation into the myxobacterial secondary metabolite argyrin via mutasynthesis

• David C. B. Siebert,
• Roman Sommer,
• Domen Pogorevc,
• Michael Hoffmann,
• Silke C. Wenzel,
• Rolf Müller and
• Alexander Titz

Beilstein J. Org. Chem. 2019, 15, 2922–2929, doi:10.3762/bjoc.15.286

• hydroxide deprotection of the ester in compound 40 provided the free acrylate 41. In parallel, Boc-protected sarcosine 42 was transformed into the SNAc thioester 43 and the Boc group was removed to give 44. Then, both building blocks, 44 and 41, were coupled to give the protected tripeptide thioester 35b in

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

• from 0° or 180°, since this interaction is governed by an equation with a vectorial product. The lack of exciton pairwise interactions between the two chromophores in positions 1 and 2 of each molecule could be due to the intercalation of a third chromophore between the two former in a parallel