Et₃N/DMSO-supported one-pot synthesis of highly fluorescent β-carboline-linked benzothiophenones via sulfur insertion and estimation of the photophysical properties

• Dharmender Singh,
• Vipin Kumar and
• Virender Singh

Beilstein J. Org. Chem. 2020, 16, 1740–1753, doi:10.3762/bjoc.16.146

• ] which were attributed to the presence of an electrophilic as well as a nucleophilic functionality in this natural product [1]. Encouraged by the applications of β-carboline and benzothiophene motifs in medicinal and materials chemistry, it was envisaged to construct a β-carboline-based novel molecular

Facile synthesis of 7-alkyl-1,2,3,4-tetrahydro-1,8-naphthyridines as arginine mimetics using a Horner–Wadsworth–Emmons-based approach

• Rhys A. Lippa,
• John A. Murphy and
• Tim N. Barrett

Beilstein J. Org. Chem. 2020, 16, 1617–1626, doi:10.3762/bjoc.16.134

• 13.8) [1] replicating the side-on salt-bridge binding interaction made between the guanidinium functionality of arginine and an aspartic acid residue in the protein. Consequently, this moiety has been used in various integrin inhibitors (Figure 1) [2][3][4][5][6][7][8]. Current routes to install

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

The McKenna reaction – avoiding side reactions in phosphonate deprotection

• Katarzyna Justyna,
• Joanna Małolepsza,
• Damian Kusy,
• Waldemar Maniukiewicz and
• Katarzyna M. Błażewska

Beilstein J. Org. Chem. 2020, 16, 1436–1446, doi:10.3762/bjoc.16.119

• from the reaction mixture by washing with aqueous sodium carbonate solution. The model compounds used for this study (in red: the functionality of the molecules vulnerable to side reactions). Schematic overview of the McKenna reaction including the decomposition of BTMS in protic solvents. The desired

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• -palladated complexes 4 with CO in methanol is a good option to promote the liberation of the organic cyclobutane, while retaining the functionalities already present (C–F, C–Cl, C–NO2, C–CF3 and –C(H)=C(H)– groups) and introducing a new functionality, i.e., the methoxycarbonyl group, selectively at the ortho

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• . Protons H-8 and H-9 showed three-bond couplings (J = 8.2 Hz), while H-9 showed a weak four-bond correlation with H-5 (J = 1.9 Hz). Relatively intense cross peaks from H-5 and H-9 to the deshielded carbon C-7 (δC 152.8) suggested the oxygen functionality at the meta-position to C-5 and C-9. Intense HMBC

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• transport properties with positive solvatochromism. Whilst 7a showed very low emission intensity, 7b showed very high emission intensity. It is noted that the conjugation in compound 7b encompasses the N atom of the carbazole ring and the formyl functionality (viz. the donor/acceptor units of the ICT

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

• Phil M. Pithan,
• Sören Steup and
• Heiko Ihmels

Beilstein J. Org. Chem. 2020, 16, 904–916, doi:10.3762/bjoc.16.82

• upon the addition of Hg2+ may have been caused by the low propensity of these cations to coordinate to the imine functionality and/or the inability to be involved in the subsequent electron transfer. Conclusion The spirooxazine–quinolizinium conjugates 3a and 3b were synthesized by a base-catalyzed

Reaction of indoles with aromatic fluoromethyl ketones: an efficient synthesis of trifluoromethyl(indolyl)phenylmethanols using K₂CO₃/n-Bu₄PBr in water

• Thanigaimalai Pillaiyar,
• Masoud Sedaghati and
• Gregor Schnakenburg

Beilstein J. Org. Chem. 2020, 16, 778–790, doi:10.3762/bjoc.16.71

• product 3a by excluding A for the next catalytic cycle. Further, to prove this hypothesis the following control experiments were performed. The reaction of 1-methylindole (1l) with 2a failed to provide the product (Scheme 4). It suggests that the indole having a free NH-functionality is important to

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

• the Oestreich group in 2016 [27]. The reaction could be performed using CuCN as catalyst in the absence of a ligand. A wide variety of triflates 9, including some containing a remote tosylate, bromide, alkene, or alkyne functionality, afforded the desired alkylsilanes 10–16 in fair to good yields

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

• Information File 1, Figure S7) and δ 6.57 and 7.63 ppm with a J value of 15 Hz for compound 18 (Supporting Information File 1, Figure S9) as inferred by 1H NMR analysis. The resulting Suzuki-coupled products 16 and 18, were subjected to benzylic oxidation expecting the olefin functionality would facilitate

Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands

• Shohei Mimura,
• Sho Mizushima,
• Yohei Shimizu and
• Masaya Sawamura

Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50

• methoxy group (in L2), the enantioselectivity drastically dropped to −10% ee, while the yield remained 99% (Table 1, entry 2). Similarly, N,N'-dimesityl-NHC L3, which lacked an oxygen functionality in the N-aryl group, showed poor enantioselectivity (9% ee) with high yield (99% yield, Table 1, entry 3

Exploring the scope of DBU-promoted amidations of 7-methoxycarbonylpterin

• Anna R. Bockman and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2020, 16, 509–514, doi:10.3762/bjoc.16.46

• activation of the methyl ester of 7-CMP (1), the use of an amine with an additional ester functionality can therefore pose a limitation in what this reaction may tolerate. Yields were diminished for this reaction, owing to a side reaction whereby the amine effectively polymerizes. However, the desired

• product was still accessible within a short reaction time, and easily purified [20]. This highlighted a limitation of the reaction, but nevertheless showed the reaction may be used in tethering additional reactive functionality to the pterin for future diversification. In an effort to better understand

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

• in a given application which can be either a sensitizer, initiator, staining, activator or a filter material just to name a few possible examples. Unfortunately, literature often does not clearly distinguish between their functionality. Besides cyanines, there were made huge efforts to synthesize

• provides the living nature of the process as well as control over the control of functionality as confirmed by the spectroscopic analyses, and chain extension and block copolymerization experiments [138]. The same strategies were also performed in NIR region using NIR sensitizers comprising cationic

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• sterically crowded biaryl ligands as they showed outstanding performances [8]. Phosphines with imidazole and imidazoline functional groups present some interesting features. The imidazolium functionality mimics active sites in biological molecules [83][84]. The ionic nature adds another dimension to the

p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies

• Panagiotis S. Gritzapis,
• Panayiotis C. Varras,
• Nikolaos-Panagiotis Andreou,
• Katerina R. Katsani,
• Konstantinos Dafnopoulos,
• George Psomas,
• Zisis V. Peitsinis,
• Alexandros E. Koumbis and
• Konstantina C. Fylaktakidou

Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33

• presence of DNA. Based on our interest in the chemistry and biology of the oxime functionality [54][55][56][57], as well as in their DNA photolytic interaction upon UV irradiation [9][10][11][43] we have decided to investigate the behaviour of carefully designed O-carbamoyl derivatives of p-pyridine

Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo

• Alexander Sailer,
• Franziska Ermer,
• Yvonne Kraus,
• Rebekkah Bingham,
• Ferdinand H. Lutter,
• Julia Ahlfeld and
• Oliver Thorn-Seshold

Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14

• effects, due to its many survival-critical roles, as well as non-functionality of the modified tubulin product. For example, knockout approaches have only been described for single isoforms of α/β-tubulin, and these cannot deliver the dynamic reversibility and effect-specificity that is required for

Photocontrolled DNA minor groove interactions of imidazole/pyrrole polyamides

• Sabrina Müller,
• Jannik Paulus,
• Jochen Mattay,
• Heiko Ihmels,
• Veronica I. Dodero and
• Norbert Sewald

Beilstein J. Org. Chem. 2020, 16, 60–70, doi:10.3762/bjoc.16.8

• peptides or small molecules, thereby controlling geometry and functionality. E-to-Z photoisomerization usually is achieved upon irradiation at 350 nm (π–π* transition), while the Z-to-E isomerization proceeds photochemically upon irradiation at >400 nm (n–π* transition) or thermally. Photoswitchable

• substance, once located at the DNA target, with an external stimulus. Azobenzenes are photoswitchable molecules capable of generating significant structural changes in peptides or small molecules, thereby controlling their geometry and functionality upon irradiation [10][11][12][13]. While isomerization of

• was proven amenable for the light-induced triggering of transcription [24], photoswitchable polyamides that can act as selective DNA minor groove binders displaying tunable affinity have not yet been reported [29][30]. We envisaged that control of the geometry and functionality could be achieved upon

SnCl₄-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives

• Kesatebrhan Haile Asressu and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2019, 15, 2990–2999, doi:10.3762/bjoc.15.295

• distinguished these alcohols by selective protection of the OH-7 functionality as 2,7-anhydro-Neu5Ac, leaving position OH-4 free for glycosylation upon protection of the vicinal OH-8 and OH-9 substituents as benzylidene or acetonide rings [6]. The formation of the bicyclo[3.2.1] backbone of 2,7-anhydro-Neu5Ac

• disaccharides were cleaved and acetylated, as shown in Scheme 5. The difficulty of these reactions might have been attributed to the more liable nature of the tertiary acetal center C-1 of fucose as compared to the sterically hindered quaternary ketal functionality C-2 of the 2,7-anhydro skeleton. To our

Pigmentosins from Gibellula sp. as antibiofilm agents and a new glycosylated asperfuran from Cordyceps javanica

• Soleiman E. Helaly,
• Wilawan Kuephadungphan,
• Patima Phainuphong,
• Mahmoud A. A. Ibrahim,
• Kanoksri Tasanathai,
• Suchada Mongkolsamrit,
• Janet Jennifer Luangsa-ard,
• Souwalak Phongpaichit,
• Vatcharin Rukachaisirikul and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2968–2981, doi:10.3762/bjoc.15.293

• correlations from the methyl H-11 to H-3 and from H-3 to H-4, together with a series of HMBC correlations from H-11 to C-3/C-4, H-4 to C-4a/C-10a/C-5, H-5 to C-4/C-6/C-10a/C-9a, and from H-8 to C9/C-9a/C-6/C-7, confirmed the presence of the dihydro-α-naphthopyrone. The position of the dimethoxy functionality

Two new aromatic polyketides from a sponge-derived Fusarium

• Mada Triandala Sibero,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Ocky K. Karna Radjasa,
• Agus Sabdono,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2941–2947, doi:10.3762/bjoc.15.289

• strong absorption band at 1683 cm−1, indicating the presence of carbonyl functionality. The 13C NMR exhibited 19 carbon signals that could be assigned to eleven nonprotonated sp2 carbons (seven are oxygenated), five sp2 methine carbons, one methylene carbon, and two methyl carbons from HSQC spectral data

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

• production. As previously mentioned, one reason for this could be high specificity of the biosynthetic machinery which might require a full length phosphopantetheine moiety or even a PCP bound substrate, for condensation to take place. To verify the functionality of the truncated argyrin biosynthesis operon

One-pot synthesis of substituted pyrrolo[3,4-b]pyridine-4,5-diones based on the reaction of N-(1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-oxo-2-arylethyl)acetamide with amines

• Valeriya G. Melekhina,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Vitaly S. Mityanov,
• Artem N. Fakhrutdinov,
• Arkady A. Dudinov,
• Vasily A. Migulin,
• Yulia V. Nelyubina,
• Elizaveta K. Melnikova and
• Michail M. Krayushkin

Beilstein J. Org. Chem. 2019, 15, 2840–2846, doi:10.3762/bjoc.15.277

• developed, the obtained compounds were further employed in the synthesis of pyrrolopyridinones 1. The presence of the two key reactive groups in adjacent positions in 7, the acetamide moiety and the enaminoketone functionality, should allow for an intramolecular condensation and the formation of the target

Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• activation with cycles of violet and green light. Due to the very long-lived metastable cis configuration, 4FAB in vivo use could be of great promise for long term biological studies. Further chemical functionalization of this 4FAB probe with a maleimide functionality allowed clean cross-linking with

• ][20] compared to 2, so a simple one-step route can be used to install the maleimides. It is this functionality that allows coupling (often called "tethering", symbolized as "t" for tetherable in Scheme 1) of the probe with mutant proteins. In our case, we developed a three-step route to install the

• ][13], specifically the spectral separation of the n–π* transitions of the trans and cis configurations. Since the maleimide functionality of 1 is quite hydrolytically sensitive at neutral pH, we characterized precursor 2. This photochrome underwent the expected trans–cis isomerization (Figure 2a). The

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• chirally modified electrodes Electrochemical oxidation reactions have long served as substantial synthetic tool because of their ability to increase the functionality of organic molecules via reversing the polarity of electron-rich functional groups and thereby generating highly reactive intermediates