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.

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines
Abstract The imidazo[1,2-a]pyridine moiety is present in drugs with several biological activities. The most direct way of obtaining this nucleus is the Groebke–Blackburn–Bienaymé three-component reaction (GBB-3CR) between aminopyridines, aldehydes, and isocyanides under both Lewis and Brønsted acid catalysis. However, several catalysts for this reaction have major drawbacks such as being expensive, extremely dangerous, strong oxidizing, and even explosive. In this scenario, heteropolyacids emerge as greener and safer alternatives due to their very strong Brønsted acidity. In particular, phosphotu...
Source: Beilstein Journal of Organic Chemistry - March 19, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: GBB-3CR imidazo[1,2-a]pyridine microwave phosphotungstic acid Full Research Paper Source Type: research

A laterally-fused N-heterocyclic carbene framework from polysubstituted aminoimidazo[5,1-b]oxazol-6-ium salts
Abstract A polysubstituted 3-aminoimidazo[5,1-b]oxazol-6-ium framework has been accessed from a new nitrenoid reagent by a two-step ynamide annulation and imidazolium ring-formation sequence. Metalation with Au(I), Cu(I) and Ir(I) at the C2 position provides an L-shaped NHC ligand scaffold that has been validated in gold-catalysed alkyne hydration and arylative cyclisation reactions. Beilstein J. Org. Chem. 2024, 20, 621–627. doi:10.3762/bjoc.20.54 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - March 18, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: annulation carbene gold imidazolium NHC Letter Source Type: research

Chemical and biosynthetic potential of Penicillium shentong XL-F41
Abstract Penicillium strains are renowned for producing diverse secondary metabolites with unique structures and promising bioactivities. Our chemical investigations, accompanied by fermentation media optimization, of a newly isolated fungus, Penicillium shentong XL-F41, led to the isolation of twelve compounds. Among these are two novel indole terpene alkaloids, shentonins A and B (1 and 2), and a new fatty acid 3. Shentonin A (1) is distinguished by an unusual methyl modification at the oxygen atom of the typical succinimide ring, a feature not seen in the structurally similar brocaeloid D. Additionally, shentonin A (1) ...
Source: Beilstein Journal of Organic Chemistry - March 15, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: genome analysis indole terpene alkaloid natural products Penicillium structure elucidation Full Research Paper Source Type: research

Introduction of a human- and keyboard-friendly N-glycan nomenclature
Abstract In the beginning was the word. But there were no words for N-glycans, at least, no simple words. Next to chemical formulas, the IUPAC code can be regarded as the best, most reliable and yet immediately comprehensible annotation of oligosaccharide structures of any type from any source. When it comes to N-glycans, the venerable IUPAC code has, however, been widely supplanted by highly simplified terms for N-glycans that count the number of antennae or certain components such as galactoses, sialic acids and fucoses and give only limited room for exact structure description. The highly illustrative – and fortun...
Source: Beilstein Journal of Organic Chemistry - March 15, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: N-glycans nomenclature structural features Perspective Source Type: research

A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A
In this study, we verify the activity for one enzyme in this pathway. We show that Hyg17 is a myo-inositol dehydrogenase that has a unique substrate scope when compared to other myo-inositol dehydrogenases. Furthermore, we analyze sequences from the protein family containing Hyg17 and discuss genome mining strategies that target this protein family to identify biosynthetic clusters for natural product discovery. Beilstein J. Org. Chem. 2024, 20, 589–596. doi:10.3762/bjoc.20.51 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - March 14, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: aminocyclitol biosynthesis hygromycin A inositol dehydrogenase myo-inositol Full Research Paper Source Type: research

Recent developments in the engineered biosynthesis of fungal meroterpenoids
Abstract Meroterpenoids are hybrid compounds that are partially derived from terpenoids. This group of natural products displays large structural diversity, and many members exhibit beneficial biological activities. This mini-review highlights recent advances in the engineered biosynthesis of meroterpenoid compounds with C15 and C20 terpenoid moieties, with the reconstruction of fungal meroterpenoid biosynthetic pathways in heterologous expression hosts and the mutagenesis of key enzymes, including terpene cyclases and α-ketoglutarate (αKG)-dependent dioxygenases, that contribute to the structural diversity. Nota...
Source: Beilstein Journal of Organic Chemistry - March 13, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: α KG-dependent dioxygenases enzyme engineering fungal meroterpenoids synthetic biology terpene cyclases Review Source Type: research

Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O – H insertion/base-promoted cyclization involving diazoarylidene succinimides
Abstract A facile approach to novel medicinally relevant spiro heterocyclic scaffolds (namely furan-2(5H)-ones, tetrahydrofurans and pyrans spiro-conjugated with the succinimide ring) has been developed. The protocol consists of Rh(II)-catalyzed insertion of heterocyclic carbenes derived from diazoarylidene succinimides (DAS) into the O–H bond of propiolic/allenic acids or brominated alcohols, followed by base-promoted cyclization to afford the target spirocyclic compounds in good to high yields. Beilstein J. Org. Chem. 2024, 20, 561–569. doi:10.3762/bjoc.20.48 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - March 11, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: diazoarylidene succinimides intramolecular cyclization rhodium(II) carbene O – H insertion spirocycles Full Research Paper Source Type: research

Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study
Abstract We theoretically analyze possible multiple conformations of protein molecules immobilized by 1-pyrenebutanoic acid succinimidyl ester (PASE) linkers on graphene. The activation barrier between two bi-stable conformations exhibited by PASE is confirmed to be based on the steric hindrance effect between a hydrogen on the pyrene group and a hydrogen on the alkyl group of this molecule. Even after the protein is supplemented, this steric hindrance effect remains if the local structure of the linker consisting of an alkyl group and a pyrene group is maintained. Therefore, it is likely that the kinetic behavior of a pro...
Source: Beilstein Journal of Organic Chemistry - March 11, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: biosensor DFT PASE protein surface adsorption Full Research Paper Source Type: research

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2 Н )-ones with a terminal phenanthroline group
Abstract A series of novel photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline receptor substituent was synthesized. Upon irradiation in acetonitrile or DMSO with light of 436 nm, they underwent Z–E isomerization of the C=C bond, followed by very fast N→O migration of the acyl group and the formation of nonemissive O-acylated isomers. These isomers were isolated preparatively and fully characterized by IR, 1H, and 13C NMR spectroscopy as well as HRMS and XRD methods. The reverse thermal reaction was catalyzed by protonic acids. N-Acylated compoun...
Source: Beilstein Journal of Organic Chemistry - March 11, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: fluorescence molecular switches → O acyl rearrangement naked eye effect photochromism Full Research Paper Source Type: research

Switchable molecular tweezers: design and applications
Abstract Switchable molecular tweezers are a unique class of molecular switches that, like their macroscopic analogs, exhibit mechanical motion between an open and closed conformation in response to stimuli. Such systems constitute an essential component of artificial molecular machines. This review will present selected examples of switchable molecular tweezers and their potential applications. The first part will be devoted to chemically responsive tweezers, including stimuli such as pH, metal coordination, and anion binding. Then, redox-active and photochemical tweezers will be presented. Beilstein J. Org. Chem. 2024, ...
Source: Beilstein Journal of Organic Chemistry - March 1, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: coordination molecular recognition molecular switches photoswitch redox supramolecular chemistry Review Source Type: research

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors
Abstract The present work covers novel herbicidal lead structures that contain a 2,3-dihydro[1,3]thiazolo[4,5-b]pyridine scaffold as structural key feature carrying a substituted phenyl side chain. These new compounds show good acyl-ACP thioesterase inhibition in line with strong herbicidal activity against commercially important weeds in broadacre crops, e.g., wheat and corn. The desired substituted 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines were prepared via an optimized BH3-mediated reduction involving tris(pentafluorophenyl)borane as a strong Lewis acid. Remarkably, greenhouse trials showed that some of the target compou...
Source: Beilstein Journal of Organic Chemistry - March 1, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: 2,3-dihydro[1,3]thiazolo[4,5-b]pyridine acyl-ACP thioesterase bioisostere herbicide heterocycle Full Research Paper Source Type: research

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination
Abstract Kinetic studies on the intramolecular hydroamination of protected variants of 2,2-diphenylpent-4-en-1-amine were carried out under a variety of conditions with cationic gold catalysts supported by phosphine ligands. The impact of ligand on gold, protecting group on nitrogen, and solvent and additive on reaction rates was determined. The most effective reactions utilized more Lewis basic ureas, and more electron-withdrawing phosphines. A DCM/alcohol cooperative effect was quantified, and a continuum of isotope effects was measured with low KIE’s in the absence of deuterated alcoholic solvent, increasing to la...
Source: Beilstein Journal of Organic Chemistry - February 29, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: alkene hydroamination general acid catalysis gold catalysis isotope effect phosphine ligand effect solvent effect Full Research Paper Source Type: research

A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001
In this study, a collection of rare actinomycetes at Kitasato University has been screened for potential novel compound producers. Among the rare actinomycetes, Saccharopolyspora sp. KR21-0001 isolated from soil on Ōha Island, Okinawa, Japan was selected as a potential producer. The strain was cultured in 20 L of production medium in a jar fermenter and the culture broth was extracted. Further purification revealed the presence of a new compound designated KR21-0001A (1). The structure was elucidated by NMR, and the absolute stereochemistry was determined by advanced Marfey’s method. The results indicated that 1...
Source: Beilstein Journal of Organic Chemistry - February 29, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: antioxidant activity dihydroxybenzoic acid analog rare actinomycetes Full Research Paper Source Type: research

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas
Abstract Solutions of 1,3-diketones and 1,3-ketoester derivatives react with fluorine to give the corresponding 2,2-difluoro-1,3-dicarbonyl derivatives in the presence of quinuclidine. Quinuclidine reacts with fluorine in situ to generate a fluoride ion that facilitates limiting enolization processes, and an electrophilic N–F fluorinating agent that is reactive towards neutral enol species. Beilstein J. Org. Chem. 2024, 20, 460–469. doi:10.3762/bjoc.20.41 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - February 28, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: difluorination difluoromethylene direct fluorination electrophilic fluorination organofluorine Full Research Paper Source Type: research

Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793
Abstract Pseudallenes A and B (1 and 2), the new and rare examples of sulfur-containing ovalicin derivatives, along with three known analogues 3–5, were isolated and identified from the culture extract of Pseudallescheria boydii CS-793, a fungus obtained from the deep-sea cold seep sediments. Their structures were established by detailed interpretation of NMR spectroscopic and mass spectrometric data. X-ray crystallographic analysis confirmed and established the structures and absolute configurations of compounds 1–3, thus providing the first characterized crystal structure of an ovalicin-type sesquiterpenoid. ...
Source: Beilstein Journal of Organic Chemistry - February 28, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: antimicrobial activity cold seep Pseudallescheria boydii sesquiterpenoid Full Research Paper Source Type: research