Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• in terms of available access routes to it and the number of drugs containing this motif. The lack of well-organized literature and well-documented experimental reports is one of the problems faced by those who just started working with biguanides. Indeed, biguanides are not the most obvious chemical

• structures to handle: their hydrogen-bonding and complexation properties complicate their isolation and purification, and the numerous tautomeric forms and partially exchangeable protons render the analysis sometimes tricky. Mostly, biguanides suffer from an evident lack of knowledge and efficient procedures

¹⁹F NMR as a tool in chemical biology

• Diana Gimenez,
• Aoife Phelan,
• Cormac D. Murphy and
• Steven L. Cobb

Beilstein J. Org. Chem. 2021, 17, 293–318, doi:10.3762/bjoc.17.28

• introduction of unnatural amino acids into proteins have been reviewed extensively elsewhere [5][6][7] and here we will only discuss the most recent advances. The chemical structures of a selection of 19F-labelled amino acid analogues that have been utilized in 19F NMR studies in chemical biology are shown in

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

• Minzan Zuo,
• Krishnasamy Velmurugan,
• Kaiya Wang,
• Xueqi Tian and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• issues in industrial engineering. Chemical structures of representative macrocycles. Ba2+-induced intermolecular [2 + 2]-photocycloaddition of crown ether-functionalized substrates 1 and 2 to form cycloadduct 3. Republished with permission of The Royal Society of Chemistry from [18] (“Supramolecular

Chemical constituents of Chaenomeles sinensis twigs and their biological activity

• Joon Min Cha,
• Dong Hyun Kim,
• Lalita Subedi,
• Zahra Khan,
• Sang Un Choi,
• Sun Yeou Kim and
• Chung Sub Kim

Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257

• which the results were expressed as a percentage of the control group (untreated cells). Chemical structures of compounds 1–13. Structure elucidation of compound 1. (A) Key COSY (blue bold) and HMBC (red arrows) correlations of 1. (B) Key NOESY (black dashed) correlations of 1. The 3D structure of 1 was

All-carbon [3 + 2] cycloaddition in natural product synthesis

• Zhuo Wang and
• Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

• Abstract Many natural products possess interesting medicinal properties that arise from their intriguing chemical structures. The highly-substituted carbocycle is one of the most common structural features in many structurally complicated natural products. However, the construction of highly-substituted

Construction of pillar[4]arene[1]quinone–1,10-dibromodecane pseudorotaxanes in solution and in the solid state

• Xinru Sheng,
• Errui Li and
• Feihe Huang

Beilstein J. Org. Chem. 2020, 16, 2954–2959, doi:10.3762/bjoc.16.245

• , chloroform-d, 298 K). Normalized UV–vis spectra: H (black); H upon adding 0.5 equiv of G (red); and H upon adding 1 equiv of G (blue). [H] = 3.00 mM. Chemical structures and schematic representation of (a) the pillar[4]arene[1]quinone H; (b) 1,10-dibromodecane (G); and (c) schematic representation of the

Using multiple self-sorting for switching functions in discrete multicomponent systems

• Amit Ghosh and
• Michael Schmittel

Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233

• . Communication between the nanoswitch 21 and the supramolecular assemblies [Cu4(22)2(24)2]4+ or [Cu6(23)2(24)3]6+ was guided by a double self-sorting. (a) The chemical structures and cartoon representations of the switch 25, the decks 26 and 27, and the bipeds 28 and 29. (b) The double self-sorting led to a

Selective recognition of ATP by multivalent nano-assemblies of bisimidazolium amphiphiles through “turn-on” fluorescence response

• Rakesh Biswas,
• Surya Ghosh,
• Shubhra Kanti Bhaumik and
• Supratim Banerjee

Beilstein J. Org. Chem. 2020, 16, 2728–2738, doi:10.3762/bjoc.16.223

• FESEM instrument. Morphologies of ATP-added PBImNs samples were recorded after addition of ATP to the PBImNs solutions followed by drying the drop casted solutions of ATP-added PBImNs on glass cover slips in a similar way. Chemical structures of (a) PBImN (N = 4, 10, 12 and 14) and (b) ATP, ADP and AMP

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

• CarbBank databases. Hence, KegDraw can be an option for the freely available tool for drawing and querying chemical structures. However, there are similar tools already available for glycan drawing with more advanced and acceptable notations. Glycan builders Sweet II. Sweet [58] is a web-based program for

• nomenclatures available to describe each monosaccharide, representing and encoding a glycan structure into a file is required for communication among scientists as well as for data processing. As a consequence, glycobiologists have proposed different graphical representations, with symbols or chemical

• structures replacing monosaccharides. The description of carbohydrate structures using standard symbolic nomenclature enables easy understanding and communication within the scientific community. Research groups working on carbohydrates have developed schematic depictions with symbols [3] and expansions with

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• article which covers almost all the unsuccessful as well as successful efforts towards the synthesis of sumanene and its congeners. The ball-and-stick representation, bowl fragments and the chemical structures of corannulene (1) and sumanene (2) are displayed in the Figure 1. 2 Synthesis of sumanene and

Synthesis of monophosphorylated lipid A precursors using 2-naphthylmethyl ether as a protecting group

• Jundi Xue,
• Ziyi Han,
• Gen Li,
• Khalisha A. Emmanuel,
• Cynthia L. McManus,
• Qiang Sui,
• Dongmian Ge,
• Qi Gao and
• Li Cai

Beilstein J. Org. Chem. 2020, 16, 1955–1962, doi:10.3762/bjoc.16.162

• the 4′-OH group. This work is currently underway in our lab. Chemical structures of hexa-acylated Escherichia coli lipid A, monophosphorylated lipid X (the reducing monosaccharide lipid A precursor), and disaccharide lipid A precursor (“disaccharide lipid X”). Enantioselective synthesis of Nap

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

• , 74.06, 71.46, 71.38, 70.92, 67.64, 62.81, 62.76, 61.80, 56.17, 37.90, 37.83, 36.75, 29.30, 25.11, 19.68, 14.16; 31P NMR (121 MHz, DMSO-d6, δ) −2.86. Chemical structures of MPD and the three structural analogs MPC-1, MPC-2, and MPC-3. The molecular probes MPC-1 and MPC-3 are photoclickable derivatives

• , whereas the probe MPC-2 bears a fluorescent tag. Chemical structures of commercially available (S)-citronellol (Cit), 4,4′-dihydroxybenzophenone (BZP), ᴅ-mannose (Man), and 1,12-dodecanediol (Dod), the main starting materials in the synthesis of MPC-1 and MPC-2. The synthetic route leading to compounds

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

• strategies could provide access to large quantities of the oligosaccharides with defined chemical structures and free from biological impurities. Among the nineteen species of Azospirillum, Azospirillum doebereinerae was isolated from the rhizosphere of the biomass producing plant, Miscanthus giganteus [20

Models of necessity

• Timothy Clark and
• Martin G. Hicks

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

• chemists represent chemical structures as two-dimensional sketches made up of atoms and bonds, simplifying the complex three-dimensional molecules comprising nuclei and electrons of the quantum mechanical description, is the everyday language of chemistry. This language uses models, particularly of bonding

• , that are not contained in the quantum mechanical description of chemical systems, but has been used to derive machine-readable formats for storing and manipulating chemical structures in digital computers. This language is fuzzy and varies from chemist to chemist but has been astonishingly successful

• and perhaps contributes with its fuzziness to the success of chemistry. It is this creative imagination of chemical structures that has been fundamental to the cognition of chemistry and has allowed thought experiments to take place. Within the everyday language, the model nature of these concepts is

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

• ]. Fourier transmission infrared spectroscopy (FTIR): Activated carbon consists mainly of carbon atoms, besides different heteroatoms such as oxygen, hydrogen, nitrogen and sulfur. Thus, different functional groups govern the surface of the activated carbons and FTIR provides information on these chemical

• structures [65]. The spectra are usually recorded between 4000 cm−1 and 400 cm−1. The most characteristic bands of functional groups on the surface of the activated carbons are ≈3500, 1700, 1610, 1420 and 1140 cm−1 which indicate free or intermolecular bonded OH groups, carbonyl (C=O) stretching vibrations

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• assist the development of environmentally benign, pure organic phosphorescent materials. (A) Transition-metal-containing and (B) pure organic phosphorescent materials reported thus far (bpy: 2,2'-bipyridine, ppy: 2-phenylpyridine, OEP: octaethylporphyrin). (A) Chemical structures of fluorescent bistolane

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• an electron acceptor in donor–acceptor systems [14]. The target compounds were obtained by nucleophilic substitution reaction of the intermediate quinazoline derivative Q1 with the corresponding donor compounds. The chemical structures were characterized by 1H NMR, 13C NMR, ATRIR spectroscopy and

• thin films of compounds 1–3 (λexc = 350 nm and PL decay curves (b) of thin films of derivatives 1–3 recorded at different emission wavelengths. Electron and hole NTOs of compounds 1–3 in the S1 excited state (vacuum). Chemical structures of exciplex-forming materials used, and visualization of white

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• presence of a palladium catalyst, with yields ranging from 27 to 50%. The chemical structures of 3–6 were confirmed by 1H and 13C NMR spectroscopy, elemental analysis and mass spectrometry. Transparent thin films of these compounds could be prepared by vacuum evaporation or by spin coating from solutions

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• electron and energy transfer. Chemical structures of the porphyrinoids and their absorption spectra: in bold are highlighted the 18 π aromatic system. Adapted from [7]. Photophysical and photochemical processes (Por = porphyrin). Adapted from [12][18]. Main dual photocatalysts and their oxidative/reductive

One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

• Ji Ma,
• Yubin Fu,
• Junzhi Liu and
• Xinliang Feng

Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72

• solution (10−5 M). Inset: photograph of a CH2Cl2 solution of 1. (b) Cyclic voltammogram of 1 (0.1 M n-Bu4NPF6 in DCM) at a scan rate of 50 mV s−1. Molecular orbitals of peropyrene derivative 6 and the dicyclopenta-fused peropyrene 1. Chemical structures of dicyclopenta-fused pyrene derivatives i–iii

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

• considering conformers at pH 7 to simulate the physiological conditions where the pH is 7.4. Results were analyzed in both Sybyl-X and UCSF Chimera. Chemical structures of the target diazine-based surrogates for the central core of panobinostat. Docking pose for panobinostat and panobinostat derivatives in

Direct borylation of terrylene and quaterrylene

• Haruka Kano,
• Keiji Uehara,
• Kyohei Matsuo,
• Hironobu Hayashi,
• Hiroko Yamada and
• Naoki Aratani

Beilstein J. Org. Chem. 2020, 16, 621–627, doi:10.3762/bjoc.16.58

• ppm; HRMS (Spiral MALDI) m/z: [M]+ calcd for C66H56, 848.4377; found, 848.4377; UV–vis (toluene): λmax (ε [104 M−1 cm−1]) = 493 (1.8), 528 (4.9) and 572 (8.6) nm; fluorescence (toluene): λmax (λex = 489 nm) = 583, 629 and 682 nm. Chemical structures of a) oligorylene-bisimides, b) oligorylenes, c) bay

Opening up connectivity between documents, structures and bioactivity

• Christopher Southan

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

• . However, we will need to await the technical applicability in respect to DARCP capture to see if this opens up connectivity. Keywords: activity data; databases; drug discovery; chemical structures; protein targets; Introduction This article assesses a key aspect of data sharing that has the potential to

• . Connectivity: This term is used for an explicit link (e.g., a URL) between a published document and the chemical structures specified therein. Implicit is not only manual navigation (e.g., link-clicking) but also that such connectivity can be made machine-readable and thus computationally interrogated at large

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• novel functional fluorescent materials. (a) Chemical structures of BODIPY (1) and dipyrromethane (2). (b) C–C bond forming alkynylations of pyrrole and its derivatives by Sonogashira coupling and electrophilic alkynylation. (c) Peripheral alkynylated BODIPY derivatives (3–6) prepared in this work. TIPS

Two antibacterial and PPARα/γ-agonistic unsaturated keto fatty acids from a coral-associated actinomycete of the genus Micrococcus

• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku,
• Nobuyasu Matsuura,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 297–304, doi:10.3762/bjoc.16.29

• ), were isolated from the culture broth of an actinomycete of the genus Micrococcus, which was associated with a stony coral, Catalaphyllia sp. Their chemical structures were elucidated by spectroscopic analysis including NMR and MS, with special assistance of spin system simulation studies for the