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.

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides
Abstract Here, we report the first transition-metal-free defluorinative cycloaddition of gem-difluoroalkenes with organic azides in morpholine as a solvent to construct fully decorated morpholine-substituted 1,2,3-triazoles. Mechanistic studies revealed the formation of an addition–elimination intermediate of morpholine and gem-difluoroalkenes prior to the triazolization reaction via two plausible pathways. Attractive elements include the regioselective and straightforward direct synthesis of fully substituted 1,2,3-triazoles, which are otherwise difficult to access, from readily available starting materials. Beilst...
Source: Beilstein Journal of Organic Chemistry - October 5, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: [3 2] cycloaddition defluorination fully decorated 1,2,3-triazoles gem-difluoroalkenes organic azides Letter Source Type: research

Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent
Abstract Rhodanines and their derivatives are known to have many pharmacological activities that can be modulated through different functionalization sites. One of the most studied modification in those scaffolds is the introduction of a benzylidene moiety on C5 via a Knoevenagel reaction. Here, a facile synthesis of 5-arylidenerhodanines via a Knoevenagel reaction in an ʟ-proline-based deep eutectic solvent (DES) is reported. This method is fast (1 h at 60 °C), easy, catalyst-free and sustainable as no classical organic solvents were used. The expected compounds are recovered by a simple filtration after hydroly...
Source: Beilstein Journal of Organic Chemistry - October 4, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: antioxidant deep eutectic solvent Knoevenagel ʟ -proline DES rhodanine Full Research Paper Source Type: research

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “ in-out ” structure, and theoretical calculations of non-covalent interactions
Abstract Resorcin[4]arenes (R[4]A) are macrocyclic compounds with a cavity structure. Despite a relatively small cavity, these compounds are capable of forming complexes with small organic molecules. The current paper focuses on the synthesis of complexes between R[4]A and secondary aliphatic amines (sec-amines). Through NMR spectroscopy, it was observed that “in-out” complexes are formed depending on the solvent. It was also found that the stoichiometry of the formed complexes depends on the size of the amine molecule. The automated interaction sites screening (aISS) made it possible to generate molecular ense...
Source: Beilstein Journal of Organic Chemistry - September 29, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: complexes DFT calculations hydrogen bond resorcin[4]arene supramolecular chemistry Full Research Paper Source Type: research

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials
Abstract Due to the lack of new antimicrobial drug discovery in recent years and an ever-growing prevalence of multidrug-resistant “superbugs”, there is a pressing need to explore alternative ways to combat pathogenic bacterial and fungal infections. Building upon our previous work in the field of medicinal phytochemistry, the present study is focused on designing, synthesizing, and testing the altered bioactivity of new variants of two original bioactive molecules found in the Argemone mexicana plant. Herein, we report upon 14 variants of berberine and four variants of chelerythrine that have been screened aga...
Source: Beilstein Journal of Organic Chemistry - September 29, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: benzylisoquinoline berberine chelerythrine drug discovery plant-derived antimicrobials Full Research Paper Source Type: research

Unraveling the role of prenyl side-chain interactions in stabilizing the secondary carbocation in the biosynthesis of variexenol B
In this study, we focus on variexenol B that is synthesized from iso-GGPP, as recently reported by Dickschat and co-workers, and investigate the possibility of through-space interactions with prenyl side chains using DFT calculations. Our calculations show that (i) the unstable secondary carbocation is stabilized by the cation–π interaction from prenyl side chains, thereby lowering the activation energy, (ii) the four-membered ring formation is completed through bridging from the exomethylene group, and (iii) the annulation from the exomethylene group proceeds in a barrier-free manner. Beilstein J. Org. Chem. 2...
Source: Beilstein Journal of Organic Chemistry - September 28, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: biosynthesis carbocation – π interaction DFT terpene Letter Source Type: research

Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid
Abstract Trichloromethyl-substituted enones (1-aryl-4,4,4-trichlorobut-2-en-1-ones, ArCOCH=CHCCl3, CCl3-enones) undergo intramolecular transformation into 3-trichloromethylindan-1-ones (CCl3-indanones) in Brønsted superacid CF3SO3H (triflic acid, TfOH) at 80 °C within 2–10 h in yields up to 92%. Protonation of the carbonyl oxygen of the starting CCl3-enones by TfOH affords the key reactive intermediates, the O-protonated forms ArC(=OH+)CH=CHCCl3, which are then cyclized into the target CCl3-indanones. These cations have been studied experimentally by means of NMR spectroscopy in TfOH and theoretically by DF...
Source: Beilstein Journal of Organic Chemistry - September 27, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: carbocations enones indanones trichloromethyl group triflic acid Full Research Paper Source Type: research

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations
Abstract In the field of organosulfur chemistry, sulfenylating agents are an important key in C–S bond formation strategies. Among various organosulfur precursors, N-sulfenylsuccinimide/phthalimide derivatives have shown highly electrophilic reactivity for the asymmetric synthesis of many organic compounds. Hence, in this review article, we focus on the application of these alternative sulfenylating reagents in organic transformations. Beilstein J. Org. Chem. 2023, 19, 1471–1502. doi:10.3762/bjoc.19.106 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - September 27, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: electrophile N-(sulfenyl)succinimides/phthalimides organic transformations organosulfur sulfenylation Review Source Type: research

Functions of enzyme domains in 2-methylisoborneol biosynthesis and enzymatic synthesis of non-natural analogs
Abstract Two aspects of the biosynthesis of the non-canonical terpene synthase for 2-methylisoborneol have been studied. Several 2-methylisoborneol synthases have a proline-rich N-terminal domain of unknown function. The results presented here demonstrate that this domain leads to a reduced enzyme activity, in addition to its ability to increase long-term solubility of the protein. Furthermore, the substrate scope of the 2-methylisoborneol synthase was investigated through enzyme incubations with several substrate analogs, giving access to two C12 monoterpenoids. Implications on the stereochemical course of the terpene cyc...
Source: Beilstein Journal of Organic Chemistry - September 22, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: biosynthesis enzymes isotopes substrate analogs terpenes Letter Source Type: research

α -(Aminomethyl)acrylates as acceptors in radical – polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping
Abstract We demonstrate that α-(aminomethyl)acrylates are suitable acceptors for 1,4-additions of dialkylzincs in aerobic conditions. The air-promoted radical–polar crossover process involves the 1,4-addition of an alkyl radical followed by homolytic substitution at the zinc atom of dialkylzinc. Coordination of the nitrogen atom to zinc enables this SH2 process which represents a rare example of alkylzinc-group transfer to a tertiary α-carbonyl radical. The zinc enolate thus formed readily undergoes β-fragmentation unless it is trapped by electrophiles in situ. Enolates of substrates having free N̵...
Source: Beilstein Journal of Organic Chemistry - September 21, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: β -amino acids tandem reactions radical – polar crossover tert-butanesulfinamide zinc radical transfer Full Research Paper Source Type: research

Application of N-heterocyclic carbene – Cu(I) complexes as catalysts in organic synthesis: a review
This article overviews applications of NHC–Cu(I) complexes as catalysts in organic synthesis over the last 12 years, which include hydrosilylation reactions, conjugate addition, [3 + 2] cycloaddition, A3 reaction, boration and hydroboration, N–H and C(sp2)–H carboxylation, C(sp2)–H alkenylation and allylation, C(sp2)–H arylation, C(sp2)–H amidation, and C(sp2)–H thiolation. Preceding the section of applications, a brief description of the structure of NHCs, nature of NHC–metal bond, and methods of preparation of NHC–Cu complexes is provided. Beilstein J. Org. Chem. 202...
Source: Beilstein Journal of Organic Chemistry - September 20, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: conjugate addition [3 2] cycloaddition reaction hydrosilylation reaction N-heterocyclic carbenes NHC – Cu complexes Cu complexes as catalyst Review Source Type: research

One-pot nucleophilic substitution – double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives
Abstract The nucleophilic substitution of benzylic bromides with sodium azide was combined with a subsequent copper-catalyzed (3 + 2) cycloaddition with terminal alkynes. This one-pot process was developed with a simple model alkyne, but then applied to more complex alkynes bearing enantiopure 1,2-oxazinyl substituents. Hence, the precursor compounds 1,2-, 1,3- or 1,4-bis(bromomethyl)benzene furnished geometrically differing bis(1,2,3-triazole) derivatives. The use of tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA) as ligand for the click step turned out to be very advantageous. The compounds with 1,2-oxazinyl end...
Source: Beilstein Journal of Organic Chemistry - September 18, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: alkynes azides copper catalysis nucleophilic substitution 1,2-oxazines Full Research Paper Source Type: research

Functional characterisation of twelve terpene synthases from actinobacteria
Abstract Fifteen type I terpene synthase homologs from diverse actinobacteria that were selected based on a phylogenetic analysis of more than 4000 amino acid sequences were investigated for their products. For four enzymes with functions not previously reported from bacterial terpene synthases the products were isolated and their structures were elucidated by NMR spectroscopy, resulting in the discovery of the first terpene synthases for (+)-δ-cadinol and (+)-α-cadinene, besides the first two bacterial (−)-amorpha-4,11-diene synthases. For other terpene synthases with functions reported from bacteria befor...
Source: Beilstein Journal of Organic Chemistry - September 15, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: actinomycetes biosynthesis enzymes NMR spectroscopy terpenes Full Research Paper Source Type: research

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation – cyclization – iodination – alkylation sequence
Abstract A library of 19 differently substituted 3-iodoindoles is generated by a consecutive four-component reaction starting from ortho-haloanilines, terminal alkynes, N-iodosuccinimide, and alkyl halides in yields of 11–69%. Initiated by a copper-free alkynylation, followed by a base-catalyzed cyclizive indole formation, electrophilic iodination, and finally electrophilic trapping of the intermediary indole anion with alkyl halides provides a concise one-pot synthesis of 3-iodoindoles. The latter are valuable substrates for Suzuki arylations, which are exemplified with the syntheses of four derivatives, some of the...
Source: Beilstein Journal of Organic Chemistry - September 14, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: alkynylation catalysis cyclization indoles iodination multicomponent reactions Full Research Paper Source Type: research

Visible-light-induced nickel-catalyzed α -hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins
Abstract A visible-light-induced nickel-catalyzed cross coupling of alkyl carboxylic acids with N-trifluoroethoxyphthalimide is described. Under purple light irradiation, an α-hydroxytrifluoroethyl radical generated from a photoactive electron donor–acceptor complex between Hantzsch ester and N-trifluoroethoxyphthalimide was subsequently engaged in a nickel-catalyzed coupling reaction with in situ-activated alkyl carboxylic acids. This convenient protocol does not require photocatalysts and metal reductants, providing a straightforward and efficient access to trifluoromethyl alkyl acyloins in good yields with br...
Source: Beilstein Journal of Organic Chemistry - September 11, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: alkyl carboxylic acids cross coupling EDA complex nickel catalysis trifluoromethyl acyloins Full Research Paper Source Type: research

Synthesis of ether lipids: natural compounds and analogues
Abstract Ether lipids are compounds present in many living organisms including humans that feature an ether bond linkage at the sn-1 position of the glycerol. This class of lipids features singular structural roles and biological functions. Alkyl ether lipids and alkenyl ether lipids (also identified as plasmalogens) correspond to the two sub-classes of naturally occurring ether lipids. In 1979 the discovery of the structure of the platelet-activating factor (PAF) that belongs to the alkyl ether class of lipids increased the interest in these bioactive lipids and further promoted the synthesis of non-natural ether lipids t...
Source: Beilstein Journal of Organic Chemistry - September 8, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: amphiphiles edelfosine GAEL glycerol lipids glycolipids ohmline plasmalogen Review Source Type: research