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.

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors
We present here a stereoselective tandem reaction based on the asymmetric conjugate addition of dialkylzinc reagents to unsaturated acylimidazoles followed by trapping of the intermediate zinc enolate with carbocations. The use of a chiral NHC ligand provides chiral zinc enolates in high enantiomeric purities. These enolates are reacted with highly electrophilic onium compounds to afford densely substituted acylimidazoles. DFT calculations helped to understand the reactivity of the zinc enolates derived from acylimidazoles and allowed their comparison with metal enolates obtained by other conjugate addition reactions. Bei...
Source: Beilstein Journal of Organic Chemistry - June 16, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: acylimidazole asymmetric catalysis carbocation conjugate addition enolate Full Research Paper Source Type: research

Light-responsive rotaxane-based materials: inducing motion in the solid state
Abstract Light-responsive rotaxane-based solid-state materials are ideal scaffolds in order to develop smart materials due to the properties provided by the mechanical bond, such as control over the dynamics of the components upon application of external stimuli. This perspective aims to highlight the relevance of these materials, by pointing out recent examples of photoresponsive materials prepared from a rotaxanated architecture in which motion of the counterparts and/or macroscopic motion of the interlocked materials are achieved. Although further development is needed, these materials are envisioned as privileged scaff...
Source: Beilstein Journal of Organic Chemistry - June 14, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: light irradiation light-responsive materials mechanical bond mechanically interlocked materials rotaxanes Perspective Source Type: research

A fluorescent probe for detection of Hg2+ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene
Abstract In this paper, tetramethyl cucurbit[6]uril (TMeQ[6]) and 1,2-bis(4-pyridyl)ethene (G) were used to construct a supramolecular fluorescent probe G@TMeQ[6]. The host–guest interaction between TMeQ[6] and G was investigated using 1H NMR spectroscopy, single-crystal X-ray diffraction and various experimental techniques. The results show that TMeQ[6] and G form an inclusion complex with a host–guest ratio of 1:1 and the equilibrium association constant (Ka) was 2.494 × 104 M−1. The G@TMeQ[6] fluorescent probe can sensitively recognize Hg2+ ions by fluorescence enhancement. The linear range is 0.3...
Source: Beilstein Journal of Organic Chemistry - June 13, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: 1,2-bis(4-pyridyl)ethane fluorescent probe Hg2 ion recognition host – guest chemistry tetramethyl cucurbit[6]uril Full Research Paper Source Type: research

Pyridine C(sp2) – H bond functionalization under transition-metal and rare earth metal catalysis
Abstract Pyridine is a crucial heterocyclic scaffold that is widely found in organic chemistry, medicines, natural products, and functional materials. In spite of the discovery of several methods for the synthesis of functionalized pyridines or their integration into an organic molecule, new methodologies for the direct functionalization of pyridine scaffolds have been developed during the past two decades. In addition, transition-metal-catalyzed C–H functionalization and rare earth metal-catalyzed reactions have flourished over the past two decades in the development of functionalized organic molecules of concern. I...
Source: Beilstein Journal of Organic Chemistry - June 12, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: C – H functionalization heterocycles pyridine rare earth metal transition-metal-catalyzed Review Source Type: research

Facile access to 3-sulfonylquinolines via Knoevenagel condensation/aza-Wittig reaction cascade involving ortho-azidobenzaldehydes and β -ketosulfonamides and sulfones
Abstract Quinoline-based sulfonyl derivatives, and especially sulfonamides, are relevant and promising structures for drug design. We have developed a new convenient protocol for the synthesis of 3-sulfonyl-substituted quinolines (sulfonamides and sulfones). The approach is based on a Knoevenagel condensation/aza-Wittig reaction cascade involving o-azidobenzaldehydes and ketosulfonamides or ketosulfones as key building blocks. The protocol is appropriate for both ketosulfonyl reagents and α-sulfonyl-substituted alkyl acetates providing the target quinoline derivatives in good to excellent yields. Beilstein J. Org. Ch...
Source: Beilstein Journal of Organic Chemistry - June 9, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: aza-Wittig reaction azides cyclocondensation quinolones sulfonamides Full Research Paper Source Type: research

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?
Abstract Reactions of thiobenzamide or thioacetamide with 4-bromo-1,1-dimethyl-1,4-dihydroisoquinoline-3(2H)-one, 4-bromoisoquinoline-1,3(2H,4H)-dione and two α-bromo(phenyl)acetamides were examined under various conditions (base, solvent, thiophile, temperature) and structure/medium features that influence product distribution (Eschenmoser coupling reaction, Hantzsch thiazole synthesis and elimination to nitriles) were identified. The key factor that enables the successful Eschenmoser coupling reaction involves the optimum balance in acidity of nitrogen and carbon atoms of the intermediary α-thioiminium salts. ...
Source: Beilstein Journal of Organic Chemistry - June 9, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: Eschenmoser coupling reaction Hantzsch thiazole synthesis isoquinolin-4-ones primary thioamides structure – reactivity relationships Full Research Paper Source Type: research

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6 π -electrocyclization of pyrimidines containing an allomaltol fragment
Abstract For the first time, we elaborated a method for the synthesis of pyrimidines containing an allomaltol unit. The suggested approach is based on the reaction of 2-(1-(dimethylamino)-3-oxo-3-arylprop-1-en-2-yl)-3-hydroxy-6-methyl-4H-pyran-4-ones with cyanamide. The photochemical behavior of the obtained pyrimidines was investigated. It was shown that for the hydroxy derivatives the main pathway of phototransformation is a 6π-electrocyclization of the 1,3,5-hexatriene system and subsequent [1,9]-H sigmatropic shift leading to dihydrobenzo[h]pyrano[2,3-f]quinazolines. At the same time, for methylated analogues the ...
Source: Beilstein Journal of Organic Chemistry - June 7, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: allomaltol dihydrobenzo[h]pyrano[2,3-f]quinazolines 6 π -electrocyclization photocyclization pyrimidines Full Research Paper Source Type: research

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities
Abstract Six new compounds, including a tetralone 1, two xanthones 2 and 3, a flavan derivative 4, and two nor-diterpenoids 7 and 8, accompanied by two known flavan derivatives 5 and 6 and a known olefine acid (9) were isolated from whole bodies of Kronopolites svenhedini (Verhoeff). The structures of the new compounds were determined by 1D and 2D nuclear magnetic resonance (NMR) and other spectroscopic methods, as well as computational methods. Selected compounds were evaluated for their biological properties against a mouse pancreatic cancer cell line and inhibitory effects on iNOS and COX-2 in RAW264.7 cells. Beilstein...
Source: Beilstein Journal of Organic Chemistry - June 7, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: arthropod iNOS Kronopolites svenhedini (Verhoeff) non-peptide small molecules Full Research Paper Source Type: research

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines
Abstract A mild, operationally convenient, and practical method for the synthesis of synthetically useful N-arylsulfonylimines from N-(arylsulfonyl)benzylamines using K2S2O8 in the presence of pyridine as a base is reported herein. In addition, a “one-pot” tandem synthesis of pharmaceutically relevant N-heterocycles by the reaction of N-arylsulfonylimines, generated in situ with ortho-substituted anilines is also reported. The key features of the protocol include the use of a green oxidant, a short reaction time (30 min), chromatography-free isolation, scalability, and economical, delivering N-arylsulfonylimine...
Source: Beilstein Journal of Organic Chemistry - June 5, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: arylsulfonylimine benzylic oxidation benzyl sulfonamide K2S2O8 sulfate radical anion Full Research Paper Source Type: research

Bromination of endo-7-norbornene derivatives revisited: failure of a computational NMR method in elucidating the configuration of an organic structure
Abstract Previously we reported on the bromination of endo-7-bromonorbornene at different temperatures yielding mixtures of addition products. The structural elucidations of the formed compounds were achieved by NMR spectroscopy. Particularly, the γ-gauche effect and long-range couplings were instrumental in assigning the stereochemistry of the adducts. However, in a recent paper, Novitskiy and Kutateladze claimed that based on an applied machine learning-augmented DFT method for computational NMR that the structure of the product, (1R,2R,3S,4S,7s)-2,3,7-tribromobicyclo[2.2.1]heptane was wrong. With the aid of their c...
Source: Beilstein Journal of Organic Chemistry - June 2, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: bromination computational NMR γ -gauche effect NOE-Diff experiments Full Research Paper Source Type: research

Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions
We report on the high potential of a honeycomb reactor for the use in aerobic oxidation under continuous-flow conditions. The honeycomb reactor is made of porous material with narrow channels separated by porous walls allowing for high density accumulation in the reactor. This structure raised the mixing efficiency of a gas–liquid reaction system, and it effectively accelerated the aerobic oxidation of benzyl alcohols to benzaldehydes under continuous-flow conditions. This reactor is a promising device for streamlining aerobic oxidation with high process safety because it is a closed system. Beilstein J. Org. Chem. ...
Source: Beilstein Journal of Organic Chemistry - May 31, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: aerobic oxidation benzaldehydes benzyl alcohols homogeneous catalyst honeycomb reactor Full Research Paper Source Type: research

Construction of hexabenzocoronene-based chiral nanographenes
Abstract The past decade witnessed remarkable success in synthetic molecular nanographenes. Encouraged by the widespread application of chiral nanomaterials, the design, and construction of chiral nanographenes is a hot topic recently. As a classic nanographene unit, hexa-peri-hexabenzocoronene generally serves as the building block for nanographene synthesis. This review summarizes the representative examples of hexa-peri-hexabenzocoronene-based chiral nanographenes. Beilstein J. Org. Chem. 2023, 19, 736–751. doi:10.3762/bjoc.19.54 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - May 30, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: chiral nanographene helicene racemization barrier Scholl reaction single-crystal X-ray diffractometry Review Source Type: research

Synthesis of imidazo[1,2-a]pyridine-containing peptidomimetics by tandem of Groebke – Blackburn – Bienaym é and Ugi reactions
Abstract Peptidomimetics with a substituted imidazo[1,2-a]pyridine fragment were synthesized by a tandem of Groebke–Blackburn–Bienaymé and Ugi reactions. The target products contain substituted imidazo[1,2-a]pyridine and peptidomimetic moieties as pharmacophores with four diversity points introduced from readily available starting materials, including scaffold diversity. A small focused compound library of 20 Ugi products was prepared and screened for antibacterial activity. Beilstein J. Org. Chem. 2023, 19, 727–735. doi:10.3762/bjoc.19.53 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - May 26, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: Groebke – Blackburn Bienaym é reaction imidazo[1,2-a]pyridine isocyanide multicomponent reaction peptidomimetic Ugi reaction Full Research Paper Source Type: research

Palladium-catalyzed enantioselective three-component synthesis of α -arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates
Abstract A palladium-catalyzed enantioselective three-component reaction of glyoxylic acid, sulfonamides and aryltrifluoroborates is described. This process provides modular access to the important α-arylglycine motif in moderate to good yields and enantioselectivies. The formed α-arylglycine products constitute useful building blocks for the synthesis of peptides or arylglycine-containing natural products. Beilstein J. Org. Chem. 2023, 19, 719–726. doi:10.3762/bjoc.19.52 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - May 25, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: amino acids asymmetric catalysis multicomponent reaction palladium catalysis Petasis reaction sulfonamides Full Research Paper Source Type: research

Strategies in the synthesis of dibenzo[b,f]heteropines
Abstract The dibenzo[b,f]azepine skeleton is important in the pharmaceutical industry, not only in terms of existing commercial antidepressants, anxiolytics and anticonvulsants, but also in reengineering for other applications. More recently, the potential of the dibenzo[b,f]azepine moiety in organic light emitting diodes and dye-sensitized solar cell dyes has been recognised, while catalysts and molecular organic frameworks with dibenzo[b,f]azepine derived ligands have also been reported. This review provides a brief overview of the different synthetic strategies to dibenzo[b,f]azepines and other dibenzo[b,f]heteropines. ...
Source: Beilstein Journal of Organic Chemistry - May 22, 2023 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: dibenzo[b,f]azepine dibenzo[b,f]heteropine dibenzo[b,f]oxepine iminostilbene synthesis Review Source Type: research