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Journals Beilstein Journal of Organic C...

Beilstein Journal of Organic Chemistry

https://read.qxmd.com/read/38410781/spatial-arrangements-of-cyclodextrin-host-guest-complexes-in-solution-studied-by-13-c-nmr-and-molecular-modelling
#21
JOURNAL ARTICLE
Konstantin Lebedinskiy, Ivan Barvík, Zdeněk Tošner, Ivana Císařová, Jindřich Jindřich, Radim Hrdina
13 C NMR spectroscopic analyses of C s symmetric guest molecules in the cyclodextrin host cavity, combined with molecular modelling and solid-state X-ray analysis, provides a detailed description of the spatial arrangement of cyclodextrin host-guest complexes in solution. The chiral cavity of the cyclodextrin molecule creates an anisotropic environment for the guest molecule resulting in a splitting of its prochiral carbon signals in 13 C NMR spectra. This signal split can be correlated to the distance of the guest atoms from the wall of the host cavity and to the spatial separation of binding sites preferred by pairs of prochiral carbon atoms...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38410780/green-and-sustainable-approaches-for-the-friedel-crafts-reaction-between-aldehydes-and-indoles
#22
REVIEW
Periklis X Kolagkis, Eirini M Galathri, Christoforos G Kokotos
The synthesis of indoles and their derivatives, more specifically bis(indolyl)methanes (BIMs), has been an area of great interest in organic chemistry, since these compounds exhibit a range of interesting biological and pharmacological properties. BIMs are naturally found in cruciferous vegetables and have been shown to be effective antifungal, antibacterial, anti-inflammatory, and even anticancer agents. Traditionally, the synthesis of BIMs has been achieved upon the acidic condensation of an aldehyde with indole, utilizing a variety of protic or Lewis acids...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38410779/mono-or-double-pd-catalyzed-c-h-bond-functionalization-for-the-annulative-%C3%AF-extension-of-1-8-dibromonaphthalene-a-one-pot-access-to-fluoranthene-derivatives
#23
JOURNAL ARTICLE
Nahed Ketata, Linhao Liu, Ridha Ben Salem, Henri Doucet
The Pd-catalyzed annulative π-extension of 1,8-dibromonaphthalene for the preparation of fluoranthenes in a single operation has been investigated. With specific arenes such as fluorobenzenes, the Pd-catalyzed double functionalization of C-H bonds yields the desired fluoranthenes. The reaction proceeds via a palladium-catalyzed direct intermolecular arylation, followed by a direct intramolecular arylation step. As the C-H bond activation of several benzene derivatives remains very challenging, the preparation of fluoranthenes from 1,8-dibromonaphthalene via Suzuki coupling followed by intramolecular C-H activation has also been investigated to provide a complementary method...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38410778/discovery-of-unguisin-j-a-new-cyclic-peptide-from-aspergillus-heteromorphus-cbs-117-55-and-phylogeny-based-bioinformatic-analysis-of-unga-nrps-domains
#24
JOURNAL ARTICLE
Sharmila Neupane, Marcelo Rodrigues de Amorim, Elizabeth Skellam
Several under-explored Aspergillus sp. produce intriguing heptapeptides containing a γ-aminobutyric acid (GABA) residue with as yet unknown biological functions. In this study, a new GABA-containing heptapeptide - unguisin J ( 1 ) - along with known unguisin B ( 2 ) were isolated from a solid culture of Aspergillus heteromorphus CBS 117.55. The structure of compound 1 was elucidated by extensive 1D and 2D NMR spectroscopic analysis including HSQC, HMBC, COSY, and 2D NOESY as well as HRESIMS. The stereochemistry of 1 and 2 was determined by Marfey's method...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38410777/enhanced-host-guest-interaction-between-10-cycloparaphenylene-10-cpp-and-5-cpp-by-cationic-charges
#25
JOURNAL ARTICLE
Eiichi Kayahara, Yoshiyuki Mizuhata, Shigeru Yamago
A dication of [5]cycloparaphenylene ([5]CPP2+ ) was selectively encapsulated by neutral [10]CPP to form the shortest double-layer carbon nanotube, [10]CPP⊃[5]CPP2+ . While the same host-guest complex consisted of neutral CPPs, [10]CPP⊃[5]CPP, was already reported, the cationic complex showed an about 20 times higher association constant in (CDCl2 )2 at 25 °C (103 mol L-1 ). Electrochemical and photophysical analyses and theoretical calculations suggested the partial electron transfer from [10]CPP to [5]CPP2+ in the complex, and this charge-transfer (CT) interaction is most likely the origin of the higher association constant of the dicationic complex than the neutral one...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38410776/elucidating-the-glycan-binding-specificity-and-structure-of-cucumis-melo-agglutinin-a-new-r-type-lectin
#26
JOURNAL ARTICLE
Jon Lundstrøm, Emilie Gillon, Valérie Chazalet, Nicole Kerekes, Antonio Di Maio, Ten Feizi, Yan Liu, Annabelle Varrot, Daniel Bojar
Plant lectins have garnered attention for their roles as laboratory probes and potential therapeutics. Here, we report the discovery and characterization of Cucumis melo agglutinin (CMA1), a new R-type lectin from melon. Our findings reveal CMA1's unique glycan-binding profile, mechanistically explained by its 3D structure, augmenting our understanding of R-type lectins. We expressed CMA1 recombinantly and assessed its binding specificity using multiple glycan arrays, covering 1,046 unique sequences. This resulted in a complex binding profile, strongly preferring C2-substituted, beta-linked galactose (both GalNAc and Fuca1-2Gal), which we contrasted with the established R-type lectin Ricinus communis agglutinin 1 (RCA1)...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38410775/mechanisms-for-radical-reactions-initiating-from-n-hydroxyphthalimide-esters
#27
JOURNAL ARTICLE
Carlos R Azpilcueta-Nicolas, Jean-Philip Lumb
Due to their ease of preparation, stability, and diverse reactivity, N -hydroxyphthalimide (NHPI) esters have found many applications as radical precursors. Mechanistically, NHPI esters undergo a reductive decarboxylative fragmentation to provide a substrate radical capable of engaging in diverse transformations. Their reduction via single-electron transfer (SET) can occur under thermal, photochemical, or electrochemical conditions and can be influenced by a number of factors, including the nature of the electron donor, the use of Brønsted and Lewis acids, and the possibility of forming charge-transfer complexes...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38379734/unveiling-the-regioselectivity-of-rhodium-i-catalyzed-2-2-2-cycloaddition-reactions-for-open-cage-c-70-production
#28
JOURNAL ARTICLE
Cristina Castanyer, Anna Pla-Quintana, Anna Roglans, Albert Artigas, Miquel Solà
The regioselective functionalization of fullerenes holds significant promise for applications in the fields of medicinal chemistry, materials science, and photovoltaics. In this study, we investigate the regioselectivity of the rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions between diynes and C70 as a novel procedure for generating C70 bis(fulleroid) derivatives. The aim is to shed light on the regioselectivity of the process through both experimental and computational approaches. In addition, the photooxidation of one of the C-C double bonds in the synthesized bis(fulleroids) affords open-cage C70 derivatives having a 12-membered ring opening...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38379733/additive-controlled-chemoselective-inter-intramolecular-hydroamination-via-electrochemical-pcet-process
#29
JOURNAL ARTICLE
Kazuhiro Okamoto, Naoki Shida, Mahito Atobe
Electrochemically generated amidyl radical species produced distinct inter- or intramolecular hydroamination reaction products via a proton-coupled electron transfer (PCET) mechanism. Cyclic voltammetry (CV) analysis indicated that the chemoselectivity was derived from the size of the hydrogen bond complex, which consisted of the carbamate substrate and phosphate base, and could be controlled using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as an additive. These results provide fundamental insights for the design of PCET-based redox reaction systems under electrochemical conditions...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38379732/synthesis-of-spiropyridazine-benzosultams-by-the-4-2-annulation-reaction-of-3-substituted-benzoisothiazole-1-1-dioxides-with-1-2-diaza-1-3-dienes
#30
JOURNAL ARTICLE
Wenqing Hao, Long Wang, Jinlei Zhang, Dawei Teng, Guorui Cao
A simple and efficient method for the synthesis of spiropyridazine-benzosultams has been developed by means of [4 + 2] annulation reaction of 3-substituted benzoisothiazole 1,1-dioxides with 1,2-diaza-1,3-dienes. This approach displays advantages such as mild reaction conditions, wide substrate range tolerance, simple operation, compatibility with gram-scale preparation.
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38379731/synthesis-of-%C3%AF-conjugated-polycyclic-compounds-by-late-stage-extrusion-of-chalcogen-fragments
#31
REVIEW
Aissam Okba, Pablo Simón Marqués, Kyohei Matsuo, Naoki Aratani, Hiroko Yamada, Gwénaël Rapenne, Claire Kammerer
The " precursor approach " has proved particularly valuable for the preparation of insoluble and unstable π-conjugated polycyclic compounds (π-CPCs), which cannot be synthesized via in-solution organic chemistry, for their improved processing, as well as for their electronic investigation both at the material and single-molecule scales. This method relies on the synthesis and processing of soluble and stable direct precursors of the target π-CPCs, followed by their final conversion in situ, triggered by thermal activation, photoirradiation or redox control...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38352072/catalytic-multi-step-domino-and-one-pot-reactions
#32
EDITORIAL
Svetlana B Tsogoeva
No abstract text is available yet for this article.
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38352071/nucleophilic-functionalization-of-thianthrenium-salts-under-basic-conditions
#33
JOURNAL ARTICLE
Xinting Fan, Duo Zhang, Xiangchuan Xiu, Bin Xu, Yu Yuan, Feng Chen, Pan Gao
In recent years, S-(alkyl)thianthrenium salts have become an important means of functionalizing alcohol compounds. However, additional transition metal catalysts and/or visible light are required. Herein, a direct thioetherification/amination reaction of thianthrenium salts is realized under metal-free conditions. This strategy exhibits good functional-group tolerance, operational simplicity, and an extensive range of compatible substrates.
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38352070/photochromic-derivatives-of-indigo-historical-overview-of-development-challenges-and-applications
#34
REVIEW
Gökhan Kaplan, Zeynel Seferoğlu, Daria V Berdnikova
The importance of indigo dyes is constantly increasing with the evolution of novel textile materials and photochromic material technologies. The aim of this review article is to provide a comprehensive overview of the development of photochromic indigo derivatives from the first report on the photochromic N,N' -diacetylindigo in 1954 until now. We begin with the list of historical milestones in the development of photochromic indigo derivatives. Further, we provide a brief description of the synthetic procedures utilised to obtain indigo and its derivatives, outline the structural peculiarities, photophysical and photochemical properties of indigo and proceed with the detailed discussion of the photochromic indigo derivatives...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38352069/optimizations-of-lipid-ii-synthesis-an-essential-glycolipid-precursor-in-bacterial-cell-wall-synthesis-and-a-validated-antibiotic-target
#35
JOURNAL ARTICLE
Milandip Karak, Cian R Cloonan, Brad R Baker, Rachel V K Cochrane, Stephen A Cochrane
Lipid II is an essential glycolipid found in bacteria. Accessing this valuable cell wall precursor is important both for studying cell wall synthesis and for studying/identifying novel antimicrobial compounds. Herein, we describe optimizations to the modular chemical synthesis of lipid II and unnatural analogues. In particular, the glycosylation step, a critical step in the formation of the central disaccharide unit (GlcNAc-MurNAc), was optimized. This was achieved by employing the use of glycosyl donors with diverse leaving groups...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38352068/substitution-reactions-in-the-acenaphthene-analog-of-quino-7-8-h-quinoline-and-an-unusual-synthesis-of-the-corresponding-acenaphthylenes-by-tele-elimination
#36
JOURNAL ARTICLE
Ekaterina V Kolupaeva, Narek A Dzhangiryan, Alexander F Pozharskii, Oleg P Demidov, Valery A Ozeryanskii
The possibility of functionalization of dipyrido[3,2- e :2',3'- h ]acenaphthene containing a quino[7,8- h ]quinoline fragment and being a highly basic diazine analog of 1,8-bis(dimethylamino)naphthalene ("proton sponge") has been studied for the first time. In addition to the pronounced tendency of the title compound to form associates with an intramolecular hydrogen bond of the NHN type (new examples with the participation of pyridine rings, including self-associates are shown) and its inertness to amination reactions of the pyridine rings, the naphthalene core at positions 5(8) and the CH2 CH2 bridge (dehydrogenation) undergo chemical modifications under mild conditions, giving the corresponding acenaphthylenes...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38318462/copper-catalyzed-multicomponent-reaction-of-%C3%AE-trifluoromethyl-%C3%AE-diazo-esters-enabling-the-synthesis-of-%C3%AE-trifluoromethyl-n-n-diacyl-%C3%AE-amino-esters
#37
JOURNAL ARTICLE
Youlong Du, Haibo Mei, Ata Makarem, Ramin Javahershenas, Vadim A Soloshonok, Jianlin Han
An efficient multicomponent reaction of newly designed β-trifluoromethyl β-diazo esters, acetonitrile, and carboxylic acids via an interrupted esterification process under copper-catalyzed conditions has been developed, which affords various unsymmetrical β-trifluoromethyl N , N -diacyl-β-amino esters in good to excellent yields. The reaction features mild conditions, a wide scope of β-amino esters and carboxylic acids, and also applicability to large-scale synthesis, thus providing an efficient way for the synthesis of β-trifluoromethyl β-diacylamino esters...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38318461/correction-synthesis-of-highly-substituted-fluorenones-via-metal-free-tbhp-promoted-oxidative-cyclization-of-2-aminomethyl-biphenyls-application-to-the-total-synthesis-of-nobilone
#38
Ilya A P Jourjine, Lukas Zeisel, Jürgen Krauß, Franz Bracher
[This corrects the article DOI: 10.3762/bjoc.17.181.].
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38318460/metal-catalyzed-coupling-carbonylative-cyclizations-for-accessing-dibenzodiazepinones-an-expedient-route-to-clozapine-and-other-drugs
#39
JOURNAL ARTICLE
Amina Moutayakine, Anthony J Burke
A sequential strategy to access 10,11-dihydro-5 H -dibenzo[ b , e ][1,4]diazepinones (DBDAPs) is disclosed in this article through a palladium and copper-catalyzed amination (Buchwald-Hartwig (B-H) or Chan-Lam (C-L)) followed by a palladium-catalyzed intramolecular aminocarbonylation with Mo(CO)6 as CO surrogate (to avoid toxic CO handling) of readily available o -phenylenediamines and either 1,2-dibromobenzene or 2-bromophenylboronic acid. The 10,11-dihydro-5 H -dibenzo[ b , e ][1,4]diazepinone could be synthezised in good yield using a sequential catalytic procedure, using both C-L and B-H approaches...
2024: Beilstein Journal of Organic Chemistry
https://read.qxmd.com/read/38318459/synthesis-of-the-3-o-sulfated-tf-antigen-with-a-teg-n-3-linker-for-glycodendrimersomes-preparation-to-study-lectin-binding
#40
JOURNAL ARTICLE
Mark Reihill, Hanyue Ma, Dennis Bengtsson, Stefan Oscarson
The synthesis of gram quantities of the TF antigen (β-ᴅ-Gal-(1→3)-α-ᴅ-GalNAc) and its 3'-sulfated analogue with a TEG-N3 spacer attached is described. The synthesis of the TF antigen comprises seven steps, from a known N -Troc-protected galactosamine donor, with an overall yield of 31%. Both the spacer (85%) and the galactose moiety (79%) were introduced using thioglycoside donors in NIS/AgOTf-promoted glycosylation reactions. The 3'-sulfate was finally introduced through tin activation in benzene/DMF followed by treatment with a sulfur trioxide-trimethylamine complex in a 66% yield...
2024: Beilstein Journal of Organic Chemistry
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