Beilstein Journal of Organic Chemistry This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor
In this study, a loop photoreactor with a total volume of around 500 mL is presented for the photocatalytic hydrogen evolution using a Pt-loaded polymeric carbon nitride photocatalyst under 365 nm irradiation in the presence of sacrificial reducing agents. The fluid flow pattern of the developed photoreactor was characterized experimentally and the photon flux incident to the loop photoreactor was measured by chemical actinometry. The system displayed exceptional stability, with operation sustained over 70 hours. A design of experiment (DOE) analysis was used to systematically investigate the influence of key parameters &#...
Source: Beilstein Journal of Organic Chemistry - January 16, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: loop photoreactor parametric study photocatalytic hydrogen evolution polymeric carbon nitride solar energy storage Full Research Paper Source Type: research

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units
Abstract Large donor–acceptor scaffolds derived from polycyclic aromatic hydrocarbons (PAHs) with tunable HOMO and LUMO energies are important for several applications, such as organic photovoltaics. Here, we present a large selection of PAHs based on central indenofluorene (IF) or fluorene cores and containing various dithiafulvene (DTF) donor units that gain aromaticity upon oxidation and a variety of acceptor units, such as vinylic diesters, enediynes, and cross-conjugated radiaannulenes (RAs) that gain aromaticity upon reduction. In some cases, the DTF units are expanded by pyrrolo annelation. The optical and red...
Source: Beilstein Journal of Organic Chemistry - January 15, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: alkynes chromophores fused-ring systems heterocycles redox chemistry Full Research Paper Source Type: research

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio
Abstract We successfully prepared a surfactant-assisted carbon nanotube (CNT) liquid crystal (LC) dispersion with double-walled CNTs (DWCNTs) having a high aspect ratio (≈1378). Compared to dispersions of single-walled CNTs (SWCNTs) with lower aspect ratio, the transition concentrations from isotropic phase to biphasic state, and from biphasic state to nematic phase are lowered, which is consistent with the predictions of the Onsager theory. An aligned DWCNT film was prepared from the DWCNT dispersion by a simple bar-coating method. Regardless of the higher aspect ratio, the order parameter obtained from the film is ...
Source: Beilstein Journal of Organic Chemistry - January 11, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: aqueous dispersion bar-coating carbon nanotube coffee-ring effect liquid crystal Full Research Paper Source Type: research

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions
Abstract The reactions of 2,4-di-tert-butyl-6-(diphenylphosphino)phenol and various Michael acceptors (acrylonitrile, acrylamide, methyl vinyl ketone, several acrylates, methyl vinyl sulfone) yield the respective phosphonium phenolate zwitterions at room temperature. Nine different zwitterions were synthesized and fully characterized. Zwitterions with the poor Michael acceptors methyl methacrylate and methyl crotonate formed, but could not be isolated in pure form. The solid-state structures of two phosphonium phenolate molecules were determined by single-crystal X-ray crystallography. The bonding situation in the solid st...
Source: Beilstein Journal of Organic Chemistry - January 10, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: Lewis-base catalysis Michael acceptor reactivity phospha-Michael reaction phosphonium phenolate zwitterion Full Research Paper Source Type: research

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water
Abstract Efficient water-solubilization of nanocarbons is desirable for both their biological and material applications, but so far has mainly relied on covalent modifications or amphiphiles featuring ionic side-chains. Here, we report a facile 2–4-step synthesis of pyridinium-based, bent aromatic amphiphiles with modular nonionic side-chains (i.e., CH3 and CH2CH2(OCH2CH2)2–Y (Y = OCH3, OH, and imidazole)). The new amphiphiles quantitatively self-assemble into ≈2 nm-sized aromatic micelles in water independent of the side-chain. Importantly, efficient water-solubilization and nonionic surface modification...
Source: Beilstein Journal of Organic Chemistry - January 8, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: aromatic micelle nanocarbon nonionic surface modification pyridinium water-solubilization Full Research Paper Source Type: research

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines
Abstract A novel and efficient base-catalyzed, transition-metal-free method for the synthesis of diheterocyclic compounds connected by an amidine linker, including apart from the common 1,2,3-triazole ring, either an additional pyrimidinedione, 4-nitroimidazole, isoxazole, 1,3,4-triazole, 2-oxochromone or thiazole ring, has been developed. The process was facilitated by a strong base and includes the cycloaddition reaction of 3,3-diaminoacrylonitriles (2-cyanoacetamidines) to heterocyclic azides followed by a Cornforth-type rearrangement to the final products. The reaction is tolerant to various N-monosubstituted 3,3-diami...
Source: Beilstein Journal of Organic Chemistry - January 5, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: Cornforth rearrangement cycloaddition reactions 3,3-diaminoacrylonitriles heterocyclic azides 1,2,3-triazole Full Research Paper Source Type: research

NMRium: Teaching nuclear magnetic resonance spectra interpretation in an online platform
Abstract NMRium is the first web-based software that allows displaying, processing, interpretation, and teaching of 1D and 2D NMR data in a user-friendly interface. It can import the most common data formats (e.g., JCAMP-DX, Bruker, Varian, and Jeol). While the scope for the use of NMRium encompasses a variety of applications such as being a component in data repositories or electronic lab notebooks (ELN), performing structure elucidation or preparing raw spectral data for publication, it also excels in enhancing teaching of NMR interpretation. In this paper, we present some current possibilities of this new tool. Several ...
Source: Beilstein Journal of Organic Chemistry - January 5, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: chemical education E-learning NMR NMR spectra structure elucidation Perspective Source Type: research

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts
Abstract N-Acyl carbazoles can be efficiently produced through a single-step process using amides and cyclic diaryliodonium triflates. This convenient reaction is facilitated by copper iodide in p-xylene, using the commonly found activating ligand diglyme. We have tested this method with a wide range of amides and iodonium triflates, proving its versatility with numerous substrates. Beyond carbazoles, we also produced a variety of other N-heterocycles, such as acridines, phenoxazines, or phenazines, showcasing the robustness of our technique. In a broader sense, this new method creates two C–N bonds simultaneously ba...
Source: Beilstein Journal of Organic Chemistry - January 4, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: carbazoles heteroaromatics iodanes metal-catalyzed one-pot reaction Letter Source Type: research

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway
This study deepened our understanding of the highly reducing type II polyketide synthase system as well as the diazotization-dependent deamination pathway for the production of avenalumic acid or p-coumaric acid. Beilstein J. Org. Chem. 2024, 20, 1–11. doi:10.3762/bjoc.20.1 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - January 2, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: actinomycetes avenalumic acid biosynthesis p-coumaric acid polyketides Full Research Paper Source Type: research

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF3: the case of alkyne hydration. Chemistry vs electrochemistry
Abstract In order to replace the expensive metal/ligand catalysts and classic toxic and volatile solvents, commonly used for the hydration of alkynes, the hydration reaction of alkynes was studied in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIm-BF4) adding boron trifluoride diethyl etherate (BF3·Et2O) as catalyst. Different ionic liquids were used, varying the cation or the anion, in order to identify the best one, in terms of both efficiency and reduced costs. The developed method was efficaciously applied to different alkynes, achieving the desired hydration products with good yields. The res...
Source: Beilstein Journal of Organic Chemistry - December 28, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: alkyne hydration boron trifluoride electrochemical synthesis ionic liquids Full Research Paper Source Type: research

Long oligodeoxynucleotides: chemical synthesis, isolation via catching-by-polymerization, verification via sequencing, and gene expression demonstration
Abstract Long oligodeoxynucleotides (ODNs) are segments of DNAs having over one hundred nucleotides (nt). They are typically assembled using enzymatic methods such as PCR and ligation from shorter 20 to 60 nt ODNs produced by automated de novo chemical synthesis. While these methods have made many projects in areas such as synthetic biology and protein engineering possible, they have various drawbacks. For example, they cannot produce genes and genomes with long repeats and have difficulty to produce sequences containing stable secondary structures. Here, we report a direct de novo chemical synthesis of 400 nt ODNs, and th...
Source: Beilstein Journal of Organic Chemistry - December 21, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: automated synthesis catching-by-polymerization gene assembly long oligonucleotide synthetic biology Full Research Paper Source Type: research

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes
Abstract The synthesis of zwitterionic dithiocarboxylate adducts was achieved by deprotonating various aldiminium or 1,2,3-triazolium salts with a strong base, followed by the nucleophilic addition of the in situ-generated cyclic (alkyl)(amino) or mesoionic carbenes (CAACs or MICs) onto carbon disulfide. Nine novel compounds were isolated and fully characterized by 1H and 13C NMR, FTIR, and HRMS techniques. Moreover, the molecular structures of two CAAC·CS2 and two MIC·CS2 betaines were determined by X-ray diffraction analysis. The analytical data recorded for all these adducts were compared with those reported p...
Source: Beilstein Journal of Organic Chemistry - December 20, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: betaines carbenes ligand effects nitrogen heterocycles zwitterions Full Research Paper Source Type: research

Studying specificity in protein – glycosaminoglycan recognition with umbrella sampling
In this study, the umbrella sampling (US) approach is used to pull away a GAG ligand from the binding site and then pull it back in. We analyze the binding interactions between GAGs of three types (heparin, desulfated heparan sulfate, and chondroitin sulfate) with three different proteins (basic fibroblast growth factor, acidic fibroblast growth factor, and cathepsin K). The main focus of our study was to evaluate whether the US approach is able to reproduce experimentally obtained structures, and how useful it can be for getting a deeper understanding of GAG properties, especially protein recognition specificity and multi...
Source: Beilstein Journal of Organic Chemistry - December 19, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: glycosaminoglycan molecular docking protein – glycosaminoglycan interaction specificity RS-REMD umbrella sampling Full Research Paper Source Type: research

Construction of diazepine-containing spiroindolines via annulation reaction of α -halogenated N-acylhydrazones and isatin-derived MBH carbonates
Abstract A straightforward synthetic protocol for the efficient construction of diazepine-containing spiroindolines has been developed and proceeds through a by base-promoted annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates. The reaction mechanism of this formal [4 + 3] annulation includes the in situ generated allylic ylide, nucleophilic substitution, Michael additon, and elimination processes. Additionally, the similar reaction with α-halogenated N-tosylhydrazones also afforded N-tosyl-substituted spiro[indoline-3,5'-[1,2]diazepine] in satisfactory yields. This protoco...
Source: Beilstein Journal of Organic Chemistry - December 18, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: acylhydrazone annulation azepine MBH carbonate spirooxindole Full Research Paper Source Type: research

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides
Abstract 2,2’-Bis(4-dimethylaminophenyl)- and 2,2'-dicyclohexyl-1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazole ((N-DMBI)2 and (Cyc-DMBI)2) are quite strong reductants with effective potentials of ca. −2 V vs ferrocenium/ferrocene, yet are relatively stable to air due to the coupling of redox and bond-breaking processes. Here, we examine their use in accomplishing electron transfer-induced bond-cleavage reactions, specifically dehalogenations. The dimers reduce halides that have reduction potentials less cathodic than ca. −2 V vs ferrocenium/ferrocene, especiall...
Source: Beilstein Journal of Organic Chemistry - December 14, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: dehalogenation n-dopant reduction reductive dimerization Full Research Paper Source Type: research