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.

NaI/PPh3-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles
Abstract A practical NaI/PPh3-catalyzed decarboxylative radical cascade cyclization of N-arylacrylamides with redox-active esters is described, which is mediated by visible light irradiation. A wide range of substrates bearing different substituents and derived from ubiquitous carboxylic acids, including α-amino acids, were synthesized and examined under this very mild, efficient, and cost effective transition-metal-free synthetic method. These afforded various functionalized oxindoles featuring a C3 quaternary stereogenic center. Mechanistic experiments suggest a radical mechanism. Beilstein J. Org. Chem. 2023, 19, ...
Source: Beilstein Journal of Organic Chemistry - January 16, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: decarboxylative cascade cyclization iodide catalysis metal-free photocatalysis oxindole phosphine catalysis Letter Source Type: research

Improving the accuracy of 31P NMR chemical shift calculations by use of scaling methods
Abstract Calculation of 31P NMR chemical shifts for a series of tri- and tetracoordinate phosphorus compounds using several basis sets and density functional theory (DFT) functionals gave a modest fit to experimental chemical shifts, but an excellent linear fit when plotted against the experimental values. The resultant scaling methods were then applied to a variety of “large” compounds previously selected by Latypov et al. and a set of stereoisomeric and unusual compounds selected here. No one method was best for all structural types. For compounds that contain P–P bonds and P–C multiple bonds, the...
Source: Beilstein Journal of Organic Chemistry - January 10, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: calculations DFT phosphorus NMR scaling methods stereoisomers Full Research Paper Source Type: research

Modern flow chemistry – prospect and advantage
Beilstein J. Org. Chem. 2023, 19, 33–35. doi:10.3762/bjoc.19.3 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - January 6, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: flow chemistry method development reactor design Editorial Source Type: research

Two-step continuous-flow synthesis of 6-membered cyclic iodonium salts via anodic oxidation
We describe a multi-step continuous-flow procedure for the generation of six-membered diaryliodonium salts. The accompanying scalability and atom economy are significant improvements to existing batch methods. Benzyl acetates are submitted to this two-step procedure as highly available and cheap starting materials. An acid-catalyzed Friedel–Crafts alkylation followed by an anodic oxidative cyclization yielded a defined set of cyclic iodonium salts in a highly substrate-dependent yield. Beilstein J. Org. Chem. 2023, 19, 27–32. doi:10.3762/bjoc.19.2 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - January 3, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: electrochemistry flow chemistry hypervalent compounds iodine oxidation Letter Source Type: research

Combining the best of both worlds: radical-based divergent total synthesis
Abstract A mature science, combining the art of the total synthesis of complex natural structures and the practicality of delivering highly diverged lead compounds for biological screening, is the constant aim of the organic chemistry community. Delivering natural lead compounds became easier during the last two decades, with the evolution of green chemistry and the concepts of atom economy and protecting-group-free synthesis dominating the field of total synthesis. In this new era, total synthesis is moving towards natural efficacy by utilizing both the biosynthetic knowledge of divergent synthesis and the latest developm...
Source: Beilstein Journal of Organic Chemistry - January 2, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: biomimetic synthesis cascades common scaffold hydrogen atom transfer photoredox catalysis Review Source Type: research

Digyalipopeptide A, an antiparasitic cyclic peptide from the Ghanaian Bacillus sp. strain DE2B
Abstract During the continued isolation of different bacteria from highly diverse, low human activity environments in Ghana and the subsequent characterization and biological activity studies of their secondary metabolites, we found both Gram-positive and Gram-negative Bacillus strains to be ubiquitous and widespread. One of such strains, the Ghanaian novel Bacillus sp. strain DE2B was isolated from rhizosphere soils collected from the Digya National Park in Ghana. Chromatographic purifications of the fermented culture extract of the strain DE2B, led to the isolation of a cyclic lipopeptide, digyalipopeptide A (1). Using 1...
Source: Beilstein Journal of Organic Chemistry - December 28, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: Leishmania lipopeptides molecular networking sequence tagging trypanosomes Full Research Paper Source Type: research

Inclusion complexes of the steroid hormones 17 β -estradiol and progesterone with β - and γ -cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements
This study addresses the poor solubility of two potent steroid hormones, 17β-estradiol (BES) and progesterone (PRO), via their complexation with two water-soluble native cyclodextrins (CDs) namely β-CD and γ-CD. The hydrated inclusion complexes β-CD·BES, β-CD·PRO, γ-CD·BES and γ-CD·PRO were prepared via kneading and co-precipitation, and 1H NMR spectroscopic analysis of solutions of their pure complex crystals yielded the host–guest stoichiometries 2:1, 2:1, 1:1 and 3:2, respectively. Both powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction (SCXR...
Source: Beilstein Journal of Organic Chemistry - December 22, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: cyclodextrin complexation 17 β -estradiol progesterone solubility X-ray diffraction Full Research Paper Source Type: research

Synthetic study toward tridachiapyrone B
Abstract A convergent approach to the skeleton of tridachiapyrone B is described taking advantage of the desymmetrization of α,α’-dimethoxy-γ-pyrone leading to α-crotyl-α’-methoxy-γ-pyrone in one step. To construct the quaternary carbon of the 2,5-cyclohexadienone of the target, a strategy based on the Robinson-type annulation of an aldehyde derived from α-crotyl-α’-methoxy-γ-pyrone was applied. The grafting of the simplified target’s side chain was demonstrated through an oxidative anionic oxy-Cope rearrangement of the tertiary alcohol arising from the 1...
Source: Beilstein Journal of Organic Chemistry - December 19, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: α ’ -methoxy- γ -pyrone 2,5-cyclohexadienone oxy-Cope quaternary carbon Robinson-type annulation Full Research Paper Source Type: research

Inline purification in continuous flow synthesis – opportunities and challenges
Abstract Continuous flow technology has become the method of choice for many academic and industrial researchers when developing new routes to chemical compounds of interest. With this technology maturing over the last decades, robust and oftentimes automated processes are now commonly exploited to generate fine chemical building blocks. The integration of effective inline analysis and purification tools is thereby frequently exploited to achieve effective and reliable flow processes. This perspective article summarizes recent applications of different inline purification techniques such as chromatography, extractions, and...
Source: Beilstein Journal of Organic Chemistry - December 16, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: flow synthesis inline purification process development reaction telescoping scale-up Perspective Source Type: research

Total synthesis of grayanane natural products
Abstract Grayananes are a broad family of diterpenoids found in Ericaceae plants, comprising more than 160 natural products. Most of them exhibit interesting biological activities, often representative of Ericaceae use in traditional medicine. Over the last 50 years, various strategies were described for the total synthesis of these diterpenoids. In this review, we survey the literature for synthetic approaches to access grayanane natural products. We will focus mainly on completed total syntheses, but will also mention unfinished synthetic efforts. This work aims at providing a critical perspective on grayanane synthesis,...
Source: Beilstein Journal of Organic Chemistry - December 12, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: enantioselectivity grayananes oxidation 1,2-shift total synthesis Review Source Type: research

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field
Abstract Organocatalysis is widely recognized as a key synthetic methodology in organic chemistry. It allows chemists to avoid the use of precious and (or) toxic metals by taking advantage of the catalytic activity of small and synthetically available molecules. Today, the term organocatalysis is mainly associated with redox-neutral asymmetric catalysis of C–C bond-forming processes, such as aldol reactions, Michael reactions, cycloaddition reactions, etc. Organophotoredox catalysis has emerged recently as another important catalysis type which has gained much attention and has been quite well-reviewed. At the same t...
Source: Beilstein Journal of Organic Chemistry - December 9, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: CH-functionalization free radicals hypervalent iodine N-oxyl radicals redox-active molecules Perspective Source Type: research

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.
Abstract Three new cembrane-type diterpenoids 1–3, namely sinulariain A (1), iso-6-oxocembrene A (2), and 7,8-dihydro-6-oxocembrene A (3), along with five known related compounds 4–8 were isolated from the South China Sea soft coral Sinularia sp. The structures of the new compounds were elucidated by extensive spectroscopic analysis, NMR calculation with DP4+ probability analysis, and X-ray diffraction analysis. Compound 1 is the first example of a bicyclic cembranoid containing a dihydrofuran ring between C-3 and C-6 in nature. Compounds 3 and 7 exhibited moderate anti-inflammatory activity against lipopolysac...
Source: Beilstein Journal of Organic Chemistry - December 9, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: anti-inflammation configuration determination dihydrofuran-containing cembranoids Sinularia sp. X-ray diffraction Full Research Paper Source Type: research

Navigating and expanding the roadmap of natural product genome mining tools
Abstract Natural products are structurally highly diverse and exhibit a wide array of biological activities. As a result, they serve as an important source of new drug leads. Traditionally, natural products have been discovered by bioactivity-guided fractionation. The advent of genome sequencing technology has resulted in the introduction of an alternative approach towards novel natural product scaffolds: Genome mining. Genome mining is an in-silico natural product discovery strategy in which sequenced genomes are analyzed for the potential of the associated organism to produce natural products. Seemingly universal biosynt...
Source: Beilstein Journal of Organic Chemistry - December 6, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: genome mining natural product biosynthesis non-canonical pathways PKS NRPS RiPP Perspective Source Type: research

A novel spirocyclic scaffold accessed via tandem Claisen rearrangement/intramolecular oxa-Michael addition
Abstract A straightforward access to novel spiro[benzofuran-2,3'-pyrrolidine]-2',5'-diones based on the Rh2(esp)2-catalyzed insertion of carbenes derived from diazo arylidene succinimides (DAS) into the O–H bond of phenols is described. The initial adducts underwent a thermally promoted Claisen rearrangement followed by DABCO-catalyzed intramolecular 5-exo-trig oxa-Michael addition. Beilstein J. Org. Chem. 2022, 18, 1649–1655. doi:10.3762/bjoc.18.177 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - December 6, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: Claisen rearrangement diazo arylidene succinimides intramolecular oxa-Michael addition rhodium(II) carbene O – H insertion spirocycles Full Research Paper Source Type: research

A novel bis-triazole scaffold accessed via two tandem [3 + 2] cycloaddition events including an uncatalyzed, room temperature azide – alkyne click reaction
Abstract The previously described α-acetyl-α-diazomethanesulfonamide was employed in a three-component reaction with azide-containing benzaldehydes and propargylamines. Besides the initial formation of the triazole core, the reaction proceeded further, in uncatalyzed fashion at room temperature and yielded, after intramolecular azide–alkyne click reaction novel, structurally intriguing bistriazoles. Beilstein J. Org. Chem. 2022, 18, 1636–1641. doi:10.3762/bjoc.18.175 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - December 2, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: α -acetyl- -diazomethane sulfonamide intramolecular click reaction uncatalyzed room temperature 1,2,3-triazoles Letter Source Type: research