Synthesis of oxindoles bearing a stereogenic 3-fluorinated carbon center from 3-fluorooxindoles

2022 ◽  
Author(s):  
Yong-Liang Liu ◽  
Xiao-Ping Wang ◽  
Jie Wei ◽  
Ya Li
Keyword(s):  
Bioactive Molecules ◽  
Structural Motif ◽  
Powerful Method ◽  
Fluorinated Carbon

3,3-Disubstituted oxindole bearing a stereogenic 3-fluorinated carbon center is a privileged structural motif present in many bioactive molecules. The straightforward functionalization of 3-fluorooxindoles constitutes a powerful method for the synthesis...

scholarly journals Porous peptide frameworks generated by stacking non-self-complementary β-sheets

2014 ◽  
Vol 70 (a1) ◽  
pp. C562-C562
Author(s):  
Dmitriy Soldatov ◽  
Abdolreza Yazdani ◽  
Julia Crewson ◽  
Travis Fillion ◽  
Aaron Smith ◽  
...  
Keyword(s):  
Interlayer Space ◽  
Specific Property ◽  
Close Packing ◽  
Bioactive Molecules ◽  
Structural Motif ◽  
Supramolecular Polymers ◽  
Amino Acid Residues ◽  
Crystalline Materials ◽  
Wide Range ◽  
Β Sheet

"One of major approaches in the design of cavity space in the solids utilizes non-self-complementary molecules[1]. The irregular shape of the molecules and/or specific directionality of potential H-bonds prevent close packing of the molecules and yields various architectures hosting a second component, from inclusion compounds and co-crystals to complex non-crystalline patterns in biology. The strategy of non-self-complementary molecules has been extended in our studies to 2D supramolecular polymers based on short peptides[2]. The formation of the peptide layer with a desired overall geometry is controlled by strong, charge-assisted H-bonds (arrows in the Figure) in a β-sheet-like network as well as the segregation of hydrophobic amino acid residues into the interlayer space. The H-bonds add stability to the whole architecture while the hydrophobic groups keep the stacking layers at a distance that generates a cavity space available to a second component (encircled ""G"" in the Figure). A wide range of inclusions and co-crystals have been prepared in our group based on a series of dipeptides and higher peptide oligomers. For example, the incorporation of various organic solvents and bioactive molecules have been demonstrated for leucyl-alanine and similar dipeptides: alcohols, amides, phenols, pyridines, polyols, vitamins, scents and flavors. The crystal structure studies reveal a surprisingly persistent structural motif that can be used for engineering of crystalline materials with a specific property. We believe this type of peptide matrix may be utilized in the solid state organic synthesis [3] as reactive molecules of the second component can be oriented in a predictable way with respect to each other. "

Synthetic Approaches to 2,6-trans-Tetrahydropyrans

Synthesis ◽  
2017 ◽  
Vol 49 (22) ◽  
pp. 4899-4916 ◽  
Author(s):  
Rongbiao Tong ◽  
Zhihong Zhang
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Michael Addition ◽  
Synthetic Methods ◽  
Bioactive Molecules ◽  
Structural Motif ◽  
Heck Cyclization ◽  
Epoxide Opening ◽  
Oxocarbenium Ion ◽  
Synthetic Approaches

Being different from 2,6-cis-tetrahydropyrans (2,6-cis-THPs), the corresponding 2,6-trans-THPs are thermodynamically less stable and more challenging to construct. The fact that there are many natural products and/or bioactive molecules containing this 2,6-trans-THP subunit has led to the development of many efficient synthetic approaches to access 2,6-trans-THPs. This review summarizes various synthetic methods reported for this structural motif and/or related applications in the total synthesis of natural products.1 Introduction2 Nucleophilic Addition to an Oxocarbenium Ion (Strategy A)3 Intramolecular Oxa-Michael Addition (Strategy B)4 Intermolecular Michael Addition to Dihydropyranones (Strategy A)5 The Heck–Matsuda (Strategy A) Reaction and Oxa-Heck Cyclization (Strategy B)6 Intramolecular SN2 Substitution and Epoxide Opening (Strategy B)7 Miscellaneous Methods8 Conclusion and Outlook

A comprehensive review on pyranoindole-containing agents

2021 ◽  
Vol 28 ◽  
Author(s):  
Alessia Catalano ◽  
Domenico Iacopetta ◽  
Jessica Ceramella ◽  
Carmela Saturnino ◽  
Maria Stefania Sinicropi
Keyword(s):  
Natural Products ◽  
Heterocyclic Compounds ◽  
Biological Activities ◽  
Therapeutic Agents ◽  
Biologically Active ◽  
Bioactive Molecules ◽  
Structural Motif ◽  
Huge Number ◽  
Naturally Occurring ◽  
Active Natural

: A huge number of nitrogen-containing heterocyclic compounds are ubiquitous in natural products, pharmaceuticals, and bioactive molecules. Among these, the pyranoindole represents an important structural motif, as it constitutes the central subunit in both the biologically active natural products and therapeutic agents. Talathermophilins, notoamides, norgeamides, carneamides, and versicamides are examples of naturally occurring pyranoindoles, while the well-known etodolac and pemedolac are a tetrahydropyrano[3,4-b]indole deriving from synthetic procedures. Besides the well-known antiinflammatory and fibrinolytic activity, molecules comprising the pyranoindole framework have been demonstrated to exhibit various biological activities, such as antiulcer, antidepressant, analgesic, and antiproliferative. Herein, we report the most common natural and synthetic products bearing a pyranoindole nucleus, their syntheses, and biological activities.

On a half-forgotten but very powerful method for coherent spectroscopy of molecules

2018 ◽  
Vol 189 (03) ◽  
pp. 271-280
Author(s):  
Aleksandr A. Makarov ◽  
Evgenii A. Ryabov
Keyword(s):  
Powerful Method ◽  
Coherent Spectroscopy

Catalytic Synthesis of Cyclic Guanidines via Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Shunya Ohuchi ◽  
Hiroki Koyama ◽  
Hiroki Shigehisa
Keyword(s):  
Hydrogen Atom ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Catalytic Synthesis ◽  
Membered Ring ◽  
Biologically Active ◽  
Atom Transfer ◽  
Powerful Method ◽  
Protective Groups ◽  
The Common

A catalytic synthesis of cyclic guanidines, which are found in many biologically active compounds and natu-ral products, was developed, wherein transition-metal hydrogen atom transfer and radical-polar crossover were employed. This mild and functional-group tolerant process enabled the cyclization of alkenyl guanidines bearing common protective groups, such as Cbz and Boc. This powerful method not only provided the common 5- and 6-membered rings but also an unusual 7-membered ring. The derivatization of the products afforded various heterocycles. We also investigated the se-lective cyclization of mono-protected or hetero-protected (TFA and Boc) alkenyl guanidines and their further derivatiza-tions.

A Chemical Perspective to the Anti-Amyloid Action of Compounds and a Nanoparticle Based Assay for Screening Amyloid Inhibitors

2020 ◽  
Author(s):  
Nidhi Gour ◽  
Bharti Koshti
Keyword(s):  
Memory Loss ◽  
Cost Effective ◽  
Structural Motif ◽  
Rapid Screening ◽  
Stacking Interactions ◽  
Aromatic Rings ◽  
Amyloid Fibers ◽  
Aromatic Stacking ◽  
Cost Effective Technique ◽  
The Brain

Aggregation of amyloid beeta 1-42 (Aβ<sub>42</sub>) peptide causes the formation of clustered deposits knows as amyloid plaques in the brain which leads to neuronal dysfunction and memory loss and associated with many neurological disorders including Alzheimer’s and Parkinson’s. Aβ<sub>42</sub> has core structural motif with phenylalanine at the 19 and 20 positions. The diphenylalanine (FF) residue plays a crucial role in the formation of amyloid fibers and serves as model peptide for studying Aβ<sub>42 </sub>aggregation. FF self-assembles to well-ordered tubular morphology via aromatic pi-pi stackings. Our studies, suggest that the aromatic rings present in the anti-amyloidogenic compounds may interact with the pi-pi stacking interactions present in the FF. Even the compounds which do not have aromatic rings, like cyclodextrin and cucurbituril show anti-amyloid property due to the binding of aromatic ring inside the guest cavity. Hence, our studies also suggest that compounds which may have a functional moiety capable of interacting with the aromatic stacking interactions might be tested for their anti-amyloidogenic properties. Further, in this manuscript, we have proposed two novel nanoparticle based assays for the rapid screening of amyloid inhibitors. In the first assay, interaction between biotin-tagged FF peptide and the streptavidin labelled gold nanoparticles (s-AuNPs) were used. In another assay, thiol-Au interactions were used to develop an assay for detection of amyloid inhibitors. It is envisaged that the proposed analytical method will provide a simple, facile and cost effective technique for the screening of amyloid inhibitors and may be of immense practical implications to find the therapeutic remedies for the diseases associated with the protein aggregation.

Bifluoride Ion Mediated SuFEx Trifluoromethylation of Sulfonyl Fluorides and Iminosulfur Oxydifluorides

2018 ◽  
Author(s):  
Christopher J. Smedley ◽  
Bing Gao ◽  
Suhua Li ◽  
Qinheng Zheng ◽  
Andrew Molino ◽  
...  
Keyword(s):  
Breast Cancer Cells ◽  
Catalytic Mechanism ◽  
Bioactive Molecules ◽  
Chromatographic Purification ◽  
Rapid Exchange ◽  
Nucleophilic Displacement ◽  
Sulfur Fluoride ◽  
Reactions With Nucleophiles ◽  
New Generation ◽  
Selection Of

Sulfur-Fluoride Exchange (SuFEx) is the new generation click chemistry transformation exploiting the unique properties of S-F bonds and their ability to undergo near-perfect reactions with nucleophiles. We report here the first SuFEx based protocol for the efficient synthesis of pharmaceutically important triflones and bis(trifluoromethyl)sulfur oxyimines from the corresponding sulfonyl fluorides and iminosulfur oxydifluorides, respectively. The new protocol involves the rapid exchange of the S-F bond with trifluoromethyltrimethylsilane (TMSCF<sub>3</sub>) upon activation with potassium bifluoride in anhydrous DMSO. The reaction tolerates a wide selection of substrates and proceeds under mild conditions without need for chromatographic purification. A tentative catalytic mechanism is proposed supported by DFT calculations, involving formation of the free trifluoromethyl anion followed by nucleophilic displacement of the S-F through a five-coordinate intermediate. The preparation of a benzothiazole derived bis(trifluoromethyl)sulfur oxyimine with cytotoxic selectivity for MCF7 breast cancer cells demonstrates the utility of this methodology for the late-stage functionalization of bioactive molecules.<br>

Reductive Cleavage of Secondary Sulfonamides: Converting Terminal Functional Groups into Versatile Synthetic Handles

2019 ◽  
Author(s):  
Patrick Fier ◽  
Suhong Kim ◽  
Kevin M. Maloney
Keyword(s):  
Functional Groups ◽  
Late Stage ◽  
Reductive Cleavage ◽  
Bioactive Molecules ◽  
General Method

Sulfonamides are pervasive in drugs and agrochemicals, yet are typically considered as terminal functional groups rather than synthetic handles. To enable the general late-stage functionalization of secondary sulfonamides, we have developed a mild and general method to reductively cleave the N-S bonds of sulfonamides to generate sulfinates and amines, components which can further react <i>in-situ</i> to access a variety of other medicinally relevant functional groups. The utility of this platform is highlighted by the selective manipulation of several complex bioactive molecules.

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