2,732 results match your criteria Beilstein Journal of Organic Chemistry [Journal]


Synthesis of acylglycerol derivatives by mechanochemistry.

Beilstein J Org Chem 2019 29;15:811-817. Epub 2019 Mar 29.

Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany.

In recent times, many biologically relevant building blocks such as amino acids, peptides, saccharides, nucleotides and nucleosides, etc. have been prepared by mechanochemical synthesis. However, mechanosynthesis of lipids by ball milling techniques has remained essentially unexplored. Read More

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https://www.beilstein-journals.org/bjoc/articles/15/78
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http://dx.doi.org/10.3762/bjoc.15.78DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444433PMC
March 2019
1 Read

An improved synthesis of adefovir and related analogues.

Beilstein J Org Chem 2019 29;15:801-810. Epub 2019 Mar 29.

School of Chemistry, University College Cork, Cork, Ireland.

An improved synthesis of the antiviral drug adefovir is presented. Problems associated with current routes to adefovir include capricious yields and a reliance on problematic reagents and solvents, such as magnesium -butoxide and DMF, to achieve high conversions to the target. A systematic study within our laboratory led to the identification of an iodide reagent which affords higher yields than previous approaches and allows for reactions to be conducted up to 10 g in scale under milder conditions. Read More

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https://www.beilstein-journals.org/bjoc/articles/15/77
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http://dx.doi.org/10.3762/bjoc.15.77DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444443PMC
March 2019
1 Read

A diastereoselective approach to axially chiral biaryls via electrochemically enabled cyclization cascade.

Beilstein J Org Chem 2019 28;15:795-800. Epub 2019 Mar 28.

State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, iChEM and College of Chemistry and Chemical Engineering, Xiamen University, People's Republic of China.

A diastereoselective approach to axially chiral imidazopyridine-containing biaryls has been developed. The reactions proceed through a radical cyclization cascade to construct the biaryls with good to excellent central-to-axial chirality transfer. Read More

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http://dx.doi.org/10.3762/bjoc.15.76DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444422PMC

Stereochemical investigations on the biosynthesis of achiral ()-γ-bisabolene in .

Beilstein J Org Chem 2019 27;15:789-794. Epub 2019 Mar 27.

Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany.

A newly identified bacterial ()-γ-bisabolene synthase was used for investigating the cyclisation mechanism of the sesquiterpene. Since the stereoinformation of both chiral putative intermediates, nerolidyl diphosphate (NPP) and the bisabolyl cation, is lost during formation of the achiral product, the intriguing question of their absolute configurations was addressed by incubating both enantiomers of NPP with the recombinant enzyme, which resolved in an exclusive cyclisation of ()-NPP, while ()-NPP that is non-natural to the ()-γ-bisabolene synthase was specifically converted into ()-β-farnesene. A hypothetical enzyme mechanistic model that explains these observations is presented. Read More

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http://dx.doi.org/10.3762/bjoc.15.75DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444425PMC

Azologization of serotonin 5-HT receptor antagonists.

Beilstein J Org Chem 2019 25;15:780-788. Epub 2019 Mar 25.

Institute of Organic Chemistry, University of Regensburg, 93053 Regensburg, Germany.

The serotonin 5-hydroxytryptamine 3 receptor (5-HTR) plays a unique role within the seven classes of the serotonin receptor family, as it represents the only ionotropic receptor, while the other six members are G protein-coupled receptors (GPCRs). The 5-HT receptor is related to chemo-/radiotherapy provoked emesis and dysfunction leads to neurodevelopmental disorders and psychopathologies. Since the development of the first serotonin receptor antagonist in the early 1990s, the range of highly selective and potent drugs expanded based on various chemical structures. Read More

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https://www.beilstein-journals.org/bjoc/articles/15/74
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http://dx.doi.org/10.3762/bjoc.15.74DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444460PMC
March 2019
1 Read

Hoveyda-Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring. Synthesis of stable, industrially scalable, highly efficient ruthenium metathesis catalysts and 2-vinylbenzylamine ligands as their precursors.

Beilstein J Org Chem 2019 22;15:769-779. Epub 2019 Mar 22.

Organic Chemistry Department, Faculty of Science, Peoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya St., Moscow 117198, Russian Federation.

A novel and efficient approach to the synthesis of 2-vinylbenzylamines is reported. This involves obtaining 2-vinylbenzylamine ligands from tetrahydroisoquinoline by alkylation and reduction followed by the Hofmann cleavage. The resultant 2-vinylbenzylamines allowed us to obtain new Hoveyda-Grubbs catalysts, which were thoroughly characterised by NMR, ESIMS, and X-ray crystallography. Read More

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https://www.beilstein-journals.org/bjoc/articles/15/73
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http://dx.doi.org/10.3762/bjoc.15.73DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444410PMC
March 2019
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Solid-phase synthesis of biaryl bicyclic peptides containing a 3-aryltyrosine or a 4-arylphenylalanine moiety.

Beilstein J Org Chem 2019 22;15:761-768. Epub 2019 Mar 22.

LIPPSO, Departament de Química, University of Girona, Maria Aurèlia Capmany 69, Girona 17003, Spain.

A methodology for the solid-phase synthesis of biaryl bicyclic peptides containing a Phe-Phe, a Phe-Tyr or a Tyr-Tyr motif has been devised. This approach comprises two key steps. The first one involves the cyclization of a linear peptidyl resin containing the corresponding halo- and boronoamino acids via a microwave-assisted Suzuki-Miyaura cross coupling. Read More

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http://dx.doi.org/10.3762/bjoc.15.72DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444451PMC

Diastereo- and enantioselective preparation of cyclopropanol derivatives.

Beilstein J Org Chem 2019 21;15:752-760. Epub 2019 Mar 21.

The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, 32000, Israel.

The diastereoselective carbocupration reaction of alkoxy-functionalized cyclopropene derivatives, followed by a subsequent trapping of the resulting cyclopropylmetal species with an electrophilic source of oxygen (oxenoid) afforded various tetrasubstituted cyclopropanol derivatives in high diastereo- and enantiomeric ratios. Similarly, the enantioselective copper-catalyzed carbomagnesiation/oxidation (or amination) sequence on achiral nonfunctionalized cyclopropenes provided the desired cyclopropanol (and cyclopropylamine) derivatives in excellent diastereo- and enantiomeric excesses. Read More

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http://dx.doi.org/10.3762/bjoc.15.71DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444454PMC

Tuning the stability of alkoxyisopropyl protection groups.

Beilstein J Org Chem 2019 21;15:746-751. Epub 2019 Mar 21.

Department of Chemistry, University of Helsinki, P.O.Box 55 (A.I.Virtasen aukio 1), FIN-00014 Helsinki, Finland.

Five different 2-alkoxypropan-2-yl groups are introduced as acid-labile protecting groups for the 5'- and 3'-hydroxy groups of a 2'-deoxynucleoside. All studied protecting groups were readily introduced with good to excellent yields using the appropriate enol ether as a reagent and 0.5 to 1 mol % toluenesulfonic acid as a catalyst. Read More

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https://www.beilstein-journals.org/bjoc/articles/15/70
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http://dx.doi.org/10.3762/bjoc.15.70DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444389PMC
March 2019
1 Read

Synthesis of polydicyclopentadiene using the CpTiCl/EtAlCl catalytic system and thin-layer oxidation of the polymer in air.

Beilstein J Org Chem 2019 20;15:733-745. Epub 2019 Mar 20.

National Research Tomsk Polytechnic University, Tomsk, 634050, Russian Federation.

The polymerization process of dicyclopentadiene using a multicomponent catalytic system based on bis(cyclopentadienyl)titanium dichloride and diethylaluminum chloride was studied. It was demonstrated that the application of an excess of the aluminum component leads to the formation of stable charged complexes of blue discoloration, which initiate cationic polymerization of dicyclopentadiene. Unstabilized thin layers of obtained polydicyclopentadiene undergo oxidation and structuring under atmospheric oxygen. Read More

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https://www.beilstein-journals.org/bjoc/articles/15/69
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http://dx.doi.org/10.3762/bjoc.15.69DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444398PMC
March 2019
1 Read

Synthesis of functionalized diazocines for application as building blocks in photo- and mechanoresponsive materials.

Beilstein J Org Chem 2019 20;15:727-732. Epub 2019 Mar 20.

Otto Diels Institute for Organic Chemistry, Christian-Albrechts-University, Otto-Hahn-Platz 4, 24118 Kiel, Germany.

Seven symmetrically 3,3'-substituted diazocines were synthesized. Functional groups include alcohol, azide, amine and vinyl groups, which are suitable for polymer synthesis. Upon irradiation at 385 and 530 nm the diazocines perform a reversible, pincer-type movement switching the 3,3'-distance between 6. Read More

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http://dx.doi.org/10.3762/bjoc.15.68DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444418PMC

Efficient synthesis of 4-substituted--phthalaldehyde analogues: toward the emergence of new building blocks.

Beilstein J Org Chem 2019 19;15:721-726. Epub 2019 Mar 19.

Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV) - Université du Littoral Côte d'Opale, 145 Avenue Maurice Schumann, MREI 1, 59140 Dunkerque, France.

4-Methoxy--phthalaldehyde and 4-hydroxy--phthalaldehyde are potentially useful molecules for fluorimetric analysis of a variety of amines and for the elaboration of complex molecular architectures. Nevertheless, literature generally describes their synthesis in very low yield (below 5%), mainly due to the inefficiency of the last oxidation step. In this paper, we report a reliable synthesis of 4-substituted--phthalaldehyde analogues in 51% overall yield owing to the addition of a protecting step of the unstable key intermediate 4,5-dihydroisobenzofuran-5-ol. Read More

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https://www.beilstein-journals.org/bjoc/articles/15/67
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http://dx.doi.org/10.3762/bjoc.15.67DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444388PMC
March 2019
1 Read

Homo- and hetero-difunctionalized β-cyclodextrins: Short direct synthesis in gram scale and analysis of regiochemistry.

Beilstein J Org Chem 2019 18;15:710-720. Epub 2019 Mar 18.

CycloLab, Cyclodextrin Research and Development Laboratory Ltd., llatos út 7, Budapest, H-1097, Hungary.

The regioselective difunctionalization of cyclodextrins (CDs) leading to derivatives amenable to further transformations is a daunting task due to challenging purification and unambiguous characterization of the obtained regioisomers with similar physicochemical properties. The primary-side homo-difunctionalization of β-CD can lead to three regioisomers, while the hetero-difunctionalization can generate three pairs of pseudoenantiomers. Previously, approaches with several synthetic steps, expensive reagents, high purification demands and low yields of the products have been employed. Read More

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http://dx.doi.org/10.3762/bjoc.15.66DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444459PMC

An efficient and concise access to 2-amino-4-benzothiopyran-4-one derivatives.

Beilstein J Org Chem 2019 18;15:703-709. Epub 2019 Mar 18.

State Key Laboratory of Bioactive Substance and Function of Natural Medicines & Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, 1 Xian Nong Tan Street, Beijing 100050, P. R. China.

A highly efficient and convenient protocol was developed to access 2-amino-4-benzothiopyran-4-ones through a process of conjugated addition-elimination. The sulfinyl group was proved to be the optimum leaving group by thorough investigations on the elimination of sulfide, sulfinyl, and sulfonyl groups at the 2-position of benzothiopyranone. Most 2-aminobenzothiopyranones were obtained in good to excellent yields under refluxing in isopropanol within 36 h. Read More

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http://dx.doi.org/10.3762/bjoc.15.65DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444430PMC

New sesquiterpenoids from the South China Sea soft corals and .

Beilstein J Org Chem 2019 15;15:695-702. Epub 2019 Mar 15.

State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, P. R. China.

A detailed chemical investigation of the South China Sea soft corals and yielded four new halogenated laurane-type sesquiterpenoids, namely, isobromolaurenisol (), clalaurenol A (), -laurenisol (), clalaurenol B (), and the new aromadendrane-type sesquiterpenoid claaromadendrene (), together with three known sesquiterpenoids (, , and ). Their structures were determined by extensive spectroscopic analysis and by comparison with the previously reported analogues. In a bioassay, compounds , and exhibited interesting inhibitory activities in vitro against PTP1B and NF-κB. Read More

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http://dx.doi.org/10.3762/bjoc.15.64DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423584PMC

Influence of per-O-sulfation upon the conformational behaviour of common furanosides.

Beilstein J Org Chem 2019 15;15:685-694. Epub 2019 Mar 15.

Laboratory of Glycoconjugate Chemistry, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect 47, 119991 Moscow, Russia.

The studies on the recently discovered pyranoside--furanoside rearrangement have led us to conformational investigations of furanosides upon their total sulfation. Experimental NMR data showed that in some cases drastic changes of the ring conformation occurred while sometimes only the conformation of the exocyclic C4-C5 linkage changed. Herein we describe a combined quantum chemical and NMR conformational investigation of three common monosaccharide furanosides as their propyl glycosides: α-mannose, β-glucose and β-galactose. Read More

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http://dx.doi.org/10.3762/bjoc.15.63DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423562PMC
March 2019
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Synthesis of 2-furo[2,3-]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction.

Beilstein J Org Chem 2019 14;15:679-684. Epub 2019 Mar 14.

Department of Organic Chemistry, Kaunas University of Technology, Radvilėnų pl. 19, Kaunas LT-50254, Lithuania.

Fused pyrazole ring systems are common structural motifs of numerous pharmaceutically important compounds. Nevertheless, access to derivatives of the aromatic 2-furo[2,3-]pyrazole ring system is still quite limited, and their chemistry and functional properties remain largely underexplored. The current study investigates routes to construct this system from easily accessible starting materials using metal-catalyzed reactions. Read More

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http://dx.doi.org/10.3762/bjoc.15.62DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423569PMC

The LANCA three-component reaction to highly substituted β-ketoenamides - versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives.

Beilstein J Org Chem 2019 13;15:655-678. Epub 2019 Mar 13.

Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany.

The LANCA three-component reaction of lithiated alkoxyallenes , nitriles and carboxylic acids leads to β-ketoenamides in good to excellent yields. The scope of this reaction is very broad and almost all types of nitriles and carboxylic acids have successfully been used. The alkoxy group introduced via the allene component is also variable and hence the subsequent transformation of this substituent into a hydroxy group can be performed under different conditions. Read More

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http://dx.doi.org/10.3762/bjoc.15.61DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423578PMC

Catalyst-free assembly of giant tris(heteroaryl)methanes: synthesis of novel pharmacophoric triads and model sterically crowded tris(heteroaryl/aryl)methyl cation salts.

Beilstein J Org Chem 2019 12;15:642-654. Epub 2019 Mar 12.

Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA.

A series of giant tris(heteroaryl)methanes are easily assembled by one-pot three-component synthesis by simple reflux in ethanol without catalyst or additives. Diversely substituted indoles (Ar) react with quinoline aldehydes, quinolone aldehydes, chromone aldehydes, and fluorene aldehydes (ArCHO) and coumarins (Ar) in 1:1:1 ratio to form the corresponding tris(heteroaryl)methanes (ArArAr)CH along with (ArArAr)CH triads. A series of new 2:1 triads were also synthesized by coupling substituted indoles with ArCHO. Read More

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https://www.beilstein-journals.org/bjoc/articles/15/60
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http://dx.doi.org/10.3762/bjoc.15.60DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423583PMC
March 2019
1 Read

Polyaminoazide mixtures for the synthesis of pH-responsive calixarene nanosponges.

Beilstein J Org Chem 2019 12;15:633-641. Epub 2019 Mar 12.

Dipartimento di Sicenze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), University of Palermo - V.le delle Scienze, Ed. 17, 90128 Palermo, Italy.

Two mixtures of polyaminoazides were synthesized by a nucleophilic displacement strategy providing no separation of the components. The mixtures were adequately characterized by means of combined HR-ESIMS, FTIR and NMR techniques and, despite their complexity, they were successfully used to accomplish the subsequent preparation of pH-sensitive calixarene hyper-reticulated nanosponge materials. The desired responsivity to pH variations of the nanosponges obtained was verified by means of absorption tests on a set of organic pollutant model molecules. Read More

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http://dx.doi.org/10.3762/bjoc.15.59DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423589PMC
March 2019
1 Read

Design and synthesis of multivalent α-1,2-trimannose-linked bioerodible microparticles for applications in immune response studies of infection.

Beilstein J Org Chem 2019 11;15:623-632. Epub 2019 Mar 11.

Department of Chemistry, Indiana University Bloomington, 800 E. Kirkwood Ave., Bloomington, Indiana 47405-7102, USA.

Leishmaniasis, a neglected tropical disease, currently infects approximately 12 million people worldwide with 1 to 2 million new cases each year in predominately underdeveloped countries. The treatment of the disease is severely underdeveloped due to the ability of the pathogen to evade and abate immune responses. In an effort to develop anti-leishmaniasis vaccines and adjuvants, novel carbohydrate-based probes were made to study the mechanisms of immune modulation. Read More

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http://dx.doi.org/10.3762/bjoc.15.58DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423605PMC

Design, synthesis and spectroscopic properties of crown ether-capped dibenzotetraaza[14]annulenes.

Beilstein J Org Chem 2019 11;15:617-622. Epub 2019 Mar 11.

Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland.

The first crown ether-capped dibenzotetraaza[14]annulenes (DBTAAs), featuring two macrocyclic binding sites fixed in a face-to-face orientation, were synthesized in satisfactory 26-28% isolated yields. Direct N-alkylation of 1,4,10-trioxa-7,13-diazacyclopentadecane by symmetric DBTAA derivatives bearing bromoalkoxy pendants proceed smoothly at a reasonable level of dilution (1.25 mM). Read More

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http://dx.doi.org/10.3762/bjoc.15.57DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423591PMC

Synthesis of the aglycon of scorzodihydrostilbenes B and D.

Beilstein J Org Chem 2019 6;15:610-616. Epub 2019 Mar 6.

Institute of Organic and Macromolecular Chemistry, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany.

Benzyl- and methyl-protected 2,4-dihydroxyacetophenones are added under ruthenium catalysis to 4-methoxy- and 3,4-dimethoxystyrene in a completely regioselective manner. Thus, oxygenated dihydrostilbenes are obtained that feature the skeleton of scorzodihydrostilbenes - antioxidative agents that were recently isolated from . Selective deprotection liberates the corresponding phenols, among them the aglycon of scorzodihydrostilbenes B and D. Read More

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http://dx.doi.org/10.3762/bjoc.15.56DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423597PMC
March 2019
1 Read

Selective benzylic C-H monooxygenation mediated by iodine oxides.

Beilstein J Org Chem 2019 5;15:602-609. Epub 2019 Mar 5.

Department of Chemistry and Physics, North Central College, 30 N. Brainard Street, Naperville, IL 60540 USA.

A method for the selective monooxdiation of secondary benzylic C-H bonds is described using an -oxyl catalyst and a hypervalent iodine species as a terminal oxidant. Combinations of ammonium iodate and catalytic -hydroxyphthalimide (NHPI) were shown to be effective in the selective oxidation of -butylbenzene directly to 1-phenylbutyl acetate in high yield (86%). This method shows moderate substrate tolerance in the oxygenation of substrates containing secondary benzylic C-H bonds, yielding the corresponding benzylic acetates in good to moderate yield. Read More

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http://dx.doi.org/10.3762/bjoc.15.55DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423598PMC
March 2019
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Cyclopropene derivatives of aminosugars for metabolic glycoengineering.

Beilstein J Org Chem 2019 4;15:584-601. Epub 2019 Mar 4.

University of Konstanz, Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), Universitätsstr. 10, 78457 Konstanz, Germany.

Cyclopropenes have been proven valuable chemical reporter groups for metabolic glycoengineering (MGE). They readily react with tetrazines in an inverse electron-demand Diels-Alder (DAinv) reaction, a prime example of a bioorthogonal ligation reaction, allowing their visualization in biological systems. Here, we present a comparative study of six cyclopropene-modified hexosamine derivatives and their suitability for MGE. Read More

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http://dx.doi.org/10.3762/bjoc.15.54DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423581PMC
March 2019
1 Read

Synthesis of the polyketide section of seragamide A and related cyclodepsipeptides via Negishi cross coupling.

Beilstein J Org Chem 2019 28;15:577-583. Epub 2019 Feb 28.

TU Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106 Braunschweig, Germany.

The synthesis of the polyketide section present in the potently cytotoxic marine cyclodepsipeptide jasplakinolide and related natural products, geodiamolides and seragamides, is reported. The key step is a Negishi cross coupling of ()-(3-methoxy-2-methyl-3-oxopropyl)zinc(II) bromide and an ()-iodoalkene that was synthesized via an aluminium ester enolate attack at ()-propylene oxide. The overall synthesis comprises nine steps with an overall yield of 21%. Read More

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http://dx.doi.org/10.3762/bjoc.15.53DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404460PMC
February 2019

Intramolecular cascade annulation triggered by rhodium(III)-catalyzed sequential C(sp)-H activation and C(sp)-H amination.

Beilstein J Org Chem 2019 27;15:571-576. Epub 2019 Feb 27.

Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001, Leuven, Belgium.

A rhodium(III)-catalyzed intramolecular oxidative annulation of -substituted -hydroxyacrylamides for the construction of indolizinones via sequential C(sp)-H activation and C(sp)-H amination has been developed. This approach shows excellent functional-group tolerance. The synthesized scaffold forms the core of many natural products with pharmacological relevance. Read More

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http://dx.doi.org/10.3762/bjoc.15.52DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404421PMC
February 2019

Synthesis and biological investigation of (+)-3-hydroxymethylartemisinin.

Beilstein J Org Chem 2019 27;15:567-570. Epub 2019 Feb 27.

Faculty of Chemistry and Mineralogy, Institute of Organic Chemistry, University of Leipzig, Johannisallee 29, 04301 Leipzig, Germany.

Herein, we describe a biomimetic entry to (+)-3-hydroxymethylartemisinin () as well as to the artemisinin derivatives (+)-3-hydroxymethyl-9-desmethylartemisinin () and (+)-3-hydroxymethyl-9--artemisinin (), starting from the known and readily available chiral aldehyde and alkyne . Subsequently, the synthesized compounds have been evaluated for their antimalarial activity against the drug-sensitive NF54 strain. All of them were inactive. Read More

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http://dx.doi.org/10.3762/bjoc.15.51DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404461PMC
February 2019

Low-budget 3D-printed equipment for continuous flow reactions.

Beilstein J Org Chem 2019 26;15:558-566. Epub 2019 Feb 26.

Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.

This article describes the development and manufacturing of lab equipment, which is needed for the use in flow chemistry. We developed a rack of four syringe pumps controlled by one Arduino computer, which can be manufactured with a commonly available 3D printer and readily available parts. Also, we printed various flow reactor cells, which are fully customizable for each individual reaction. Read More

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https://www.beilstein-journals.org/bjoc/articles/15/50
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http://dx.doi.org/10.3762/bjoc.15.50DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404462PMC
February 2019
9 Reads

Back to the future: Why we need enzymology to build a synthetic metabolism of the future.

Authors:
Tobias J Erb

Beilstein J Org Chem 2019 26;15:551-557. Epub 2019 Feb 26.

Max-Planck-Institute for Terrestrial Microbiology, Department of Biochemistry & Synthetic Metabolism, Karl-von-Frisch-Str. 10, D-35043 Marburg, Germany.

Biology is turning from an analytical into a synthetic discipline. This is especially apparent in the field of metabolic engineering, where the concept of synthetic metabolism has been recently developed. Compared to classical metabolic engineering efforts, synthetic metabolism aims at creating novel metabolic networks in a rational fashion from bottom-up. Read More

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http://dx.doi.org/10.3762/bjoc.15.49DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404388PMC
February 2019
1 Read

Dirhodium(II)-catalyzed [3 + 2] cycloaddition of -arylaminocyclopropane with alkyne derivatives.

Beilstein J Org Chem 2019 25;15:542-550. Epub 2019 Feb 25.

College of Chemistry, Sichuan University, Chengdu 610046, China.

Dirhodium(II) complex-catalyzed [3 + 2] reactions between -arylaminocyclopropanes and alkyne derivatives are described. The cycloaddition products proved to be versatile synthetic intermediates. -Cyclic β-amino acids and derivatives thereof can be conveniently synthesized using this cycloaddition protocol. Read More

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http://dx.doi.org/10.3762/bjoc.15.48DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404392PMC
February 2019

Synthesis and SAR of the antistaphylococcal natural product nematophin from .

Beilstein J Org Chem 2019 25;15:535-541. Epub 2019 Feb 25.

Molekulare Biotechnologie, Goethe University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany.

The repeated and improper use of antibiotics had led to an increased number of multiresistant bacteria. Therefore, new lead structures are needed. Here, the synthesis and an expanded structure-activity relationship of the simple and antistaphylococcal amide nematophin from and synthetic derivatives are described. Read More

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http://dx.doi.org/10.3762/bjoc.15.47DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404511PMC
February 2019

Selectivity in multiple multicomponent reactions: types and synthetic applications.

Beilstein J Org Chem 2019 21;15:521-534. Epub 2019 Feb 21.

Laboratory of Medicinal Chemistry, Faculty of Pharmacy and Food Sciences and Institute of Biomedicine (IBUB), University of Barcelona, Av. de Joan XXIII, 27-31, 08028 Barcelona, Spain.

Multiple multicomponent reactions reach an unparalleled level of connectivity, leading to highly complex adducts. Usually, only one type of transformation involving the same set of reactants takes place. However, in some occasions this is not the case. Read More

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http://dx.doi.org/10.3762/bjoc.15.46DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404517PMC
February 2019
2.762 Impact Factor

Design of indole- and MCR-based macrocycles as p53-MDM2 antagonists.

Beilstein J Org Chem 2019 20;15:513-520. Epub 2019 Feb 20.

Department of Drug Design, University of Groningen, Antonius Deusinglaan 1, 9700 AD Groningen, The Netherlands.

Macrocycles were designed to antagonize the protein-protein interaction p53-MDM2 based on the three-finger pharmacophore FWL. The synthesis was accomplished by a rapid, one-pot synthesis of indole-based macrocycles based on Ugi macrocyclization. The reaction of 12 different α,ω-amino acids and different indole-3-carboxaldehyde derivatives afforded a unique library of macrocycles otherwise difficult to access. Read More

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http://dx.doi.org/10.3762/bjoc.15.45DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404402PMC
February 2019
1 Read

Conformational signature of Ishikawa´s reagent using NMR information from diastereotopic fluorines.

Beilstein J Org Chem 2019 20;15:506-512. Epub 2019 Feb 20.

Department of Chemistry, Federal University of Lavras, 37200-000, Lavras, MG, Brazil.

The active species of the Ishikawa´s reagent [,-diethyl-(1,1,2,3,3,3-hexafluoropropyl)amine] is a fluorinating hexafluoropropylamine used to convert alcohols into alkyl fluorides. On the other hand, it is also an example of model compound useful to probe conformational preferences using spectroscopic information from diastereotopic fluorines. Moreover, the possibility of experiencing both the generalized anomeric and effects makes the Ishikawa´s reagent an ideal choice to study the governing stereoelectronic interactions of the conformational equilibrium of organofluorine compounds. Read More

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http://dx.doi.org/10.3762/bjoc.15.44DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404478PMC
February 2019

Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts.

Beilstein J Org Chem 2019 19;15:497-505. Epub 2019 Feb 19.

Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.

Adamantyloxyamine reacts with formaldehyde to give -(adamantyloxy)formaldimine as a room-temperature-stable compound that exists in solution in monomeric form. This product was used for reactions with α-hydroxyiminoketones leading to a new class of 2-unsubstituted imidazole 3-oxides bearing the adamantyloxy substituent at N(1). Their reactions with 2,2,4,4-tetramethylcyclobutane-1,3-dithione or with acetic acid anhydride occurred analogously to those of 1-alkylimidazole 3-oxides to give imidazol-2-thiones and imidazol-2-ones, respectively. Read More

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http://dx.doi.org/10.3762/bjoc.15.43DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404403PMC
February 2019

A chemoenzymatic synthesis of ceramide trafficking inhibitor HPA-12.

Beilstein J Org Chem 2019 18;15:490-496. Epub 2019 Feb 18.

Bio-Organic Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.

A chemoenzymatic synthesis of the title compound has been developed using an efficient and highly enantioselective lipase-catalyzed acylation in a hydrophobic ionic liquid, [bmim][PF], followed by a diastereoselective asymmetric dihydroxylation as the key steps for incorporating the stereogenic centers. The further conversion to the appropriate intermediates and subsequent acylation with lauric acid furnished the target compound. Read More

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http://dx.doi.org/10.3762/bjoc.15.42DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404422PMC
February 2019

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines.

Beilstein J Org Chem 2019 15;15:474-489. Epub 2019 Feb 15.

Faculty of Materials Science and Applied Chemistry, Riga Technical University, P. Valdena Str. 3, LV-1048 Riga, Latvia.

The synthesis of novel fluorescent N(9)-alkylated 2-amino-6-triazolylpurine and 7-deazapurine derivatives is described. A new C(2)-regioselectivity in the nucleophilic aromatic substitution reactions of 9-alkylated-2,6-diazidopurines and 7-deazapurines with secondary amines has been disclosed. The obtained intermediates, 9-alkylated-2-amino-6-azido-(7-deaza)purines, were transformed into the title compounds by CuAAC reaction. Read More

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http://dx.doi.org/10.3762/bjoc.15.41DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404417PMC
February 2019
2 Reads

Microwave-assisted synthesis of -bis(phosphinoylmethyl)amines and -tris(phosphinoylmethyl)amines bearing different substituents on the phosphorus atoms.

Beilstein J Org Chem 2019 15;15:469-473. Epub 2019 Feb 15.

Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, 1521 Budapest, Hungary.

A family of ,-bis(phosphinoylmethyl)amines bearing different substituents on the phosphorus atoms was synthesized by the microwave-assisted and catalyst-free Kabachnik-Fields reaction of (aminomethyl)phosphine oxides with paraformaldehyde and diphenylphosphine oxide. The three-component condensation of -bis(phosphinoylmethyl)amine, paraformaldehyde and a secondary phosphine oxide affording -tris(phosphinoylmethyl)amine derivatives was also elaborated. This method is a novel approach for the synthesis of the target products. Read More

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http://dx.doi.org/10.3762/bjoc.15.40DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404400PMC
February 2019

Aqueous olefin metathesis: recent developments and applications.

Beilstein J Org Chem 2019 14;15:445-468. Epub 2019 Feb 14.

Department of Chemistry, University of Basel, Building 1096, Mattenstraße 24a, Biopark Rosental, 4058, Basel, Switzerland.

Olefin metathesis is one of the most powerful C-C double-bond-forming reactions. Metathesis reactions have had a tremendous impact in organic synthesis, enabling a variety of applications in polymer chemistry, drug discovery and chemical biology. Although challenging, the possibility to perform aqueous metatheses has become an attractive alternative, not only because water is a more sustainable medium, but also to exploit biocompatible conditions. Read More

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http://dx.doi.org/10.3762/bjoc.15.39DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404410PMC
February 2019
3 Reads

LCST phase behavior of benzo-21-crown-7 with different alkyl chains.

Beilstein J Org Chem 2019 14;15:437-444. Epub 2019 Feb 14.

College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, Hunan, P. R. China.

The introduction of hydrophobic units into crown ethers can dramatically decrease the critical transition temperature of LCST and realize macroscopic phase separation at low to moderate temperature and concentration. Minor modifications in the chemical structure of crown ethers (benzo-21-crown-7, B21C7s) can effectively control the thermo-responsive properties. Read More

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http://dx.doi.org/10.3762/bjoc.15.38DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404474PMC
February 2019
1 Read

Convergent synthesis of the pentasaccharide repeating unit of the biofilms produced by .

Beilstein J Org Chem 2019 13;15:431-436. Epub 2019 Feb 13.

Bose Institute, Division of Molecular Medicine, P-1/12, C.I.T. Scheme VII M, Kolkata 700054, India.

A pentasaccharide repeating unit containing α-linked D-glucuronic acid, β-linked D-mannose, corresponding to the repeating unit of biofilms produced by has been synthesized using a stereoselective [2 + 3] convergent glycosylation strategy. The β-D-mannosidic moiety has been synthesized using a D-mannose-derived thioglycoside by a two-step activation process. Late stage TEMPO-mediated oxidation of the pentasaccharide derivative using phase-transfer reaction conditions furnished the target compound in satisfactory yield. Read More

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http://dx.doi.org/10.3762/bjoc.15.37DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404407PMC
February 2019

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives.

Beilstein J Org Chem 2019 13;15:401-430. Epub 2019 Feb 13.

Mitchell Cancer Institute, University of South Alabama, 1660 Springhill Ave., Mobile, AL 36604, USA.

The β-anomeric form of nicotinamide riboside (NR) is a precursor for nicotinamide adenine dinucleotide (NAD), a redox cofactor playing a critical role in cell metabolism. Recently, it has been demonstrated that its chloride salt (NRCl) has beneficial effects, and now NRCl is available as a dietary supplement. Syntheses and studies of analogues and derivatives of NR are of high importance to unravel the role of NR in biochemical processes in living cells and to elaborate the next generation of NR derivatives and conjugates with the view of developing novel drug and food supplement candidates. Read More

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http://dx.doi.org/10.3762/bjoc.15.36DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404419PMC
February 2019

Study on the regioselectivity of the N-ethylation reaction of -benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide.

Beilstein J Org Chem 2019 12;15:388-400. Epub 2019 Feb 12.

Instituto de Química, Universidade Federal Fluminense, Niterói, 24020-150, Brazil.

4-Oxoquinolines are a class of organic substances of great importance in medicinal chemistry, due to their biological and synthetic versatility. -1-Alkylated-4-oxoquinoline derivatives have been associated with different pharmacological activities such as antibacterial and antiviral. The presence of a carboxamide unit connected to carbon C-3 of the 4-oxoquinoline core has been associated with various biological activities. Read More

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http://dx.doi.org/10.3762/bjoc.15.35DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404479PMC
February 2019

Thiol-free chemoenzymatic synthesis of β-ketosulfides.

Beilstein J Org Chem 2019 11;15:378-387. Epub 2019 Feb 11.

INFIQC-CONICET, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Ciudad Universitaria, Córdoba, X5000HUA, Argentina.

A preparation of β-ketosulfides avoiding the use of thiols is described. The combination of a multicomponent reaction and a lipase-catalysed hydrolysis has been developed in order to obtain high chemical diversity employing a single sulfur donor. This methodology for the selective synthesis of a set of β-ketosulfides is performed under mild conditions and can be set up in one-pot two-step and on a gram-scale. Read More

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http://dx.doi.org/10.3762/bjoc.15.34DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404416PMC
February 2019
1 Read

Synthesis of -symmetric star-shaped molecules containing α-amino acids and dipeptides via Negishi coupling as a key step.

Beilstein J Org Chem 2019 8;15:371-377. Epub 2019 Feb 8.

Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai-400076, India.

We demonstrate a new synthetic strategy toward star-shaped -symmetric molecules containing α-amino acid (AAA) derivatives and dipeptides. In this regard, trimerization and Negishi cross-coupling reactions are used as the key steps starting from readily available 4'-iodoacetophenone and L-serine. These -symmetric molecules containing AAA moieties are useful to design new ligands suitable for asymmetric synthesis and peptide dendrimers. Read More

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http://dx.doi.org/10.3762/bjoc.15.33DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6369998PMC
February 2019

Annulation of 1-pyrrole-2,3-diones by thioacetamide: an approach to 5-azaisatins.

Beilstein J Org Chem 2019 7;15:364-370. Epub 2019 Feb 7.

Department of Chemistry, Perm State University, ul. Bukireva 15, Perm 614990, Russian Federation.

A novel approach to 1-pyrrolo[3,2-]pyridine-2,3-diones (5-azaisatins) has been developed via an unprecedented annulation of pyrrolo[2,1-][1,4]benzoxazine-1,2,4-triones by thioacetamide. A new way of C-H functionalization of thioacetamide has been discovered. The reaction proceeds under green catalyst-free conditions. Read More

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http://dx.doi.org/10.3762/bjoc.15.32DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6369991PMC
February 2019
1 Read

Reusable and highly enantioselective water-soluble Ru(II)--Pheox catalyst for intramolecular cyclopropanation of diazo compounds.

Beilstein J Org Chem 2019 6;15:357-363. Epub 2019 Feb 6.

Department of Environmental and Life Sciences, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-Cho, Toyohashi 441-8580, Japan.

A reusable and highly enantioselective catalyst for the intramolecular cyclopropanation of various diazo ester and Weinreb amide derivatives was developed. The reactions catalyzed by a water-soluble Ru(II)--Pheox catalyst proceeded smoothly at room temperature, affording the corresponding bicyclic cyclopropane ring-fused lactones and lactams in high yields (up to 99%) with excellent enantioselectivities (up to 99% ee). After screening of various catalysts, the Ru(II)--Pheox complex having an ammonium group proved to be crucial for the intramolecular cyclopropanation reaction in a water/ether biphasic medium. Read More

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http://dx.doi.org/10.3762/bjoc.15.31DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6369996PMC
February 2019
1 Read
2.762 Impact Factor

Tandem copper and photoredox catalysis in photocatalytic alkene difunctionalization reactions.

Beilstein J Org Chem 2019 5;15:351-356. Epub 2019 Feb 5.

Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.

Oxidative alkene difunctionalization reactions are important in synthetic organic chemistry because they can install polar functional groups onto simple non-polar alkene moieties. Many of the most common methods for these reactions rely upon the reactivity of pre-oxidized electrophilic heteroatom donors that can often be unstable, explosive, or difficult to handle. Herein, we describe a method for alkene oxyamination and diamination that utilizes simple carbamate and urea groups as nucleophilic heteroatom donors. Read More

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http://dx.doi.org/10.3762/bjoc.15.30DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6369989PMC
February 2019
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Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes.

Beilstein J Org Chem 2019 5;15:333-350. Epub 2019 Feb 5.

Laboratory of Organic Chemistry, Institute of Chemistry, Biology, Innovation (CBI), ESPCI Paris, CNRS (UMR 8231), PSL Research University, 10 rue Vauquelin, 75231 Paris Cedex 05, France.

Cyclopropenes constitute useful precursors of other classes of compounds incorporating a three-membered ring. Although the transformation of substituted cyclopropenes into alkylidenecyclopropanes can be accomplished through different strategies, this review is focusing specifically on the use of [2,3]- and [3,3]-sigmatropic rearrangements involving cyclopropenylcarbinol derivatives as substrates. These sigmatropic rearrangements, which have been developed in recent years, allow a remarkably efficient and stereoselective access to a wide variety of heterosubstituted and/or functionalized alkylidenecyclopropanes which would not be readily accessible by other strategies. Read More

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http://dx.doi.org/10.3762/bjoc.15.29DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6369978PMC
February 2019