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.

Synthesis of new representatives of A3B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations
Abstract A carboranylporphyrin of A3B-type bearing a single pentafluorophenyl ring was prepared through the regioselective nucleophilic aromatic substitution reaction of the p-fluorine atoms in 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin with 9-mercapto-m-carborane. The reaction of this porphyrin with sodium azide led to the selective substitution of the p-fluorine atom in the pentafluorophenyl substituent with an azide functionality which upon reduction with SnCl2 resulted in the formation of the corresponding porphyrin with an amino group. Pentafluorophenyl-substituted A3B-porphyrins were studied and transformed to t...
Source: Beilstein Journal of Organic Chemistry - April 12, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: bioconjugation carboranes fluorine porphyrin SNAr aromatic substitution Full Research Paper Source Type: research

Methodology for awakening the potential secondary metabolic capacity in actinomycetes
Abstract Secondary metabolites produced by actinomycete strains undoubtedly have great potential for use in applied research areas such as drug discovery. However, it is becoming difficult to obtain novel compounds because of repeated isolation around the world. Therefore, a new strategy for discovering novel secondary metabolites is needed. Many researchers believe that actinomycetes have as yet unanalyzed secondary metabolic activities, and the associated undiscovered secondary metabolite biosynthesis genes are called “silent” genes. This review outlines several approaches to further activate the metabolic po...
Source: Beilstein Journal of Organic Chemistry - April 10, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: actinomycete co-culture heat shock metabolites (HSMs) secondary metabolites silent genes Review Source Type: research

Research progress on the pharmacological activity, biosynthetic pathways, and biosynthesis of crocins
Abstract Crocins are water-soluble apocarotenoids isolated from the flowers of crocus and gardenia. They exhibit various pharmacological effects, including neuroprotection, anti-inflammatory properties, hepatorenal protection, and anticancer activity. They are often used as coloring and seasoning agents. Due to the limited content of crocins in plants and the high cost of chemical synthesis, the supply of crocins is insufficient to meet current demand. The biosynthetic pathways for crocins have been elucidated to date, which allows the heterologous production of these valuable compounds in microorganisms by fermentation. T...
Source: Beilstein Journal of Organic Chemistry - April 9, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: biosynthetic pathway crocetin crocins metabolic engineering pharmacological activity Review Source Type: research

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis
Abstract An isotopic labelling method was developed to investigate substrate binding by ketosynthases, exemplified by the second ketosynthase of the polyketide synthase BaeJ involved in bacillaene biosynthesis (BaeJ-KS2). For this purpose, both enantiomers of a 13C-labelled N-acetylcysteamine thioester (SNAC ester) surrogate of the proposed natural intermediate of BaeJ-KS2 were synthesised, including an enzymatic step with glutamate decarboxylase, and incubated with BaeJ-KS2. Substrate binding was demonstrated through 13C NMR analysis of the products against the background of various control experiments. Beilstein J. Org....
Source: Beilstein Journal of Organic Chemistry - April 5, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: bacillaene biosynthesis enzyme mechanisms isotopes trans-AT polyketide synthases Letter Source Type: research

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization
Abstract Chemoenzymatic strategies that combine synthetic and enzymatic transformations offer efficient approaches to yield target molecules, which have been increasingly employed in the synthesis of bioactive natural products. In the biosynthesis of macrocyclic nonribosomal peptides, polyketides, and their hybrids, thioesterase (TE) domains play a significant role in late-stage macrocyclization. These domains can accept mimics of native substrates in vitro and exhibit potential for use in total synthesis. This review summarizes the recent advances of TE domains in the chemoenzymatic synthesis for these natural products th...
Source: Beilstein Journal of Organic Chemistry - April 4, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: biosynthesis chemoenzymatic synthesis macrocyclic peptides macrocyclic polyketides thioesterase Review Source Type: research

Genome mining of labdane-related diterpenoids: Discovery of the two-enzyme pathway leading to ( − )-sandaracopimaradiene in the fungus Arthrinium sacchari
Abstract Labdane-related diterpenoids (LRDs) in fungi are a pharmaceutically important, but underexplored family of natural products. In the biosynthesis of fungal LRDs, bifunctional terpene cyclases (TCs) consisting of αβγ domains are generally used to synthesize the polycyclic skeletones of LRDs. Herein, we conducted genome mining of LRDs in our fungal genome database and identified a unique pair of TCs, AsPS and AsCPS, in the fungus Arthrinium sacchari. AsPS consists of catalytically active α and inactive β domains, whereas AsCPS contains βγ domains and a truncated α domain. Heter...
Source: Beilstein Journal of Organic Chemistry - April 3, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: diterpenoids fungi genome mining labdane terpene cyclase Full Research Paper Source Type: research

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes
We report the detailed background for the discovery and development of the synthesis of homopropargylic azides by the azido-alkynylation of alkenes. Initially, a strategy involving SOMOphilic alkynes was adopted, but only resulted in a 29% yield of the desired product. By switching to a radical-polar crossover approach and after optimization, a high yield (72%) of the homopropargylic azide was reached. Full insights are given about the factors that were essential for the success of the optimization process. Beilstein J. Org. Chem. 2024, 20, 701–713. doi:10.3762/bjoc.20.64 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - April 3, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: alkyne azide hypervalent iodine photoredox trifluoroborate salt Commentary Source Type: research

New variochelins from soil-isolated Variovorax sp. H002
This study focused on exploring the natural products of the soil-isolated Variovorax sp. H002, leading to the isolation of variochelins A–E (1–5), a series of lipohexapeptide siderophores. NMR and MS/MS analyses revealed that these siderophores share a common core structure – a linear hexapeptide with β-hydroxyaspartate and hydroxamate functional groups, serving in iron-binding coordination. Three new variochelins C–E (3–5) were characterized by varied fatty acyl groups at their N-termini; notably, 4 and 5 represent the first variochelins with N-terminal unsaturated fatty acyl groups. Fur...
Source: Beilstein Journal of Organic Chemistry - April 2, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: antimicrobial activity siderophore variochelin Variovorax Full Research Paper Source Type: research

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives
Abstract The new chiral ligands I–III based on derivatives of imidazolidin-4-one were synthesised and characterised. The catalytic activity and enantioselectivity of their corresponding copper(II) complexes were studied in asymmetric Henry reactions. It was found that the enantioselectivity of these catalysts is overall very high and depends on the relative configuration of the ligand used; cis-configuration of ligand affords the nitroaldols with major enantiomer S- (up to 97% ee), whereas the application of ligands with trans-configuration led to nitroaldols with major R-enantiomer (up to 96% ee). The “proline...
Source: Beilstein Journal of Organic Chemistry - April 2, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: asymmetric aldol reaction asymmetric Henry reaction chiral ligands enantioselective catalysis imidazolidine derivatives Full Research Paper Source Type: research

Organic electron transport materials
Beilstein J. Org. Chem. 2024, 20, 672–674. doi:10.3762/bjoc.20.60 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - March 28, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: acceptors electron transport material electron-deficient n-type organic semiconductors Editorial Source Type: research

Regioselective quinazoline C2 modifications through the azide – tetrazole tautomeric equilibrium
Abstract 2-Chloro-4-sulfonylquinazolines undergo functional group swap when treated with an azide nucleophile: 1) the azide replaces the sulfonyl group at the C4 position; 2) the intrinsic azide–tetrazole tautomeric equilibrium directs the nucleofugal sulfinate from the first step to replace chloride at the C2 position. This transformation is effective with quinazolines bearing electron-rich substituents. Therefore, the title transformations are demonstrated on the 6,7-dimethoxyquinazoline core, which is present in pharmaceutically active substances. The methodology application is showcased by transforming the obtain...
Source: Beilstein Journal of Organic Chemistry - March 28, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: aromatic nucleophilic substitution azide – tetrazole equilibrium 4-azido-2-sulfonylquinazolines sulfonyl group dance Full Research Paper Source Type: research

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines
Abstract Herein, we report a visible-light-mediated palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines, affording unsaturated γ- and ε-amino acid derivatives with diverse structures. In this methodology, the diazo compound readily transforms into a hybrid α-ester alkylpalladium radical with the release of dinitrogen. The radical intermediate selectively adds to the double bond of a 1,3-diene or allene, followed by the allylpalladium radical-polar crossover path and selective allylic substitution with the amine substrate, thereby le...
Source: Beilstein Journal of Organic Chemistry - March 27, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: carboamination diazo chemistry palladium catalysis radical-polar crossover three-component reaction Full Research Paper Source Type: research

Enhanced reactivity of Li+@C60 toward thermal [2 + 2] cycloaddition by encapsulated Li+ Lewis acid
In this study, we report the synthesis of Li+@C60 derivatives via the thermal [2 + 2] cycloaddition reaction of styrene derivatives, achieving significantly higher yields of monofunctionalized Li+@C60 compared to previously reported reactions. Furthermore, by combining experimental and theoretical approaches, we clarified the range of applicable substrates for the thermal [2 + 2] cycloaddition of Li+@C60, highlighting the expanded scope of this straightforward and selective functionalization method. Beilstein J. Org. Chem. 2024, 20, 653–660. doi:10.3762/bjoc.20.58 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - March 25, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: electron transfer fullerene ion-endohedral fullerene Lewis acid catalyst thermal [2 2] cycloaddition Full Research Paper Source Type: research

Isolation and structure determination of a new analog of polycavernosides from marine Okeania sp. cyanobacterium
Abstract Polycavernoside E (1), a new polycavernoside analog, was isolated from a marine Okeania sp. cyanobacterium. The relative configuration was elucidated primarily by analyzing the two dimensional nuclear magnetism resonance (2D NMR) data. The absolute configuration was clarified by comparing the electronic circular dichroism (ECD) data of 1 with those of known analogs. Polycavernoside E (1) exhibited moderate antitrypanosomal activity against Trypanosoma brucei rhodesiense. Furthermore, the isolation of polycavernoside E (1) from marine cyanobacteria provides additional evidence that marine cyanobacteria, and not red...
Source: Beilstein Journal of Organic Chemistry - March 21, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: macrolide glycoside marine cyanobacterium marine natural products polycavernosides terminal alkyne Full Research Paper Source Type: research

Production of non-natural 5-methylorsellinate-derived meroterpenoids in Aspergillus oryzae
In this study, we constructed engineered metabolic pathways in the fungus Aspergillus oryzae to expand the molecular diversity of meroterpenoids. We employed the 5-methylorsellinic acid (5-MOA) synthase FncE and three additional biosynthetic enzymes for the formation of (6R,10′R)-epoxyfarnesyl-5-MOA methyl ester, which served as a non-native substrate for four terpene cyclases from DMOA-derived meroterpenoid pathways. As a result, we successfully generated six unnatural 5-MOA-derived meroterpenoid species, demonstrating the effectiveness of our approach in the generation of structural analogues of meroterpenoids. Be...
Source: Beilstein Journal of Organic Chemistry - March 20, 2024 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: biosynthesis meroterpenoids natural products pathway engineering terpene cyclases Letter Source Type: research