- Synthesis and crystal structure of dimethyl-7-oxabicyclo[2.2.1]hept-5-ene exo,exo-2,3-dicarboxylate
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Dimethyl-7-oxabicyclo[2.2.1]hept-5-ene exo,exo-2,3-dicarboxylate (1) was prepared by Fisher esterification of 7-oxabicyclo[2.2.1]-hept-5-ene exo-2,3-dicarboxylic anhydride (2) in methanol. The colorless plates obtained were characterized by FT-IR, 1H- and 13C-NMR, TGA-DSC, and single crystal X-ray diffraction. The material crystallizes in space group P21/c, with a = 9.2375(14) A, b = 12.8757(18) A, c = 9.4608(15) A, β = 115.327(3)°, V = 1017.1(3) A3, and Z = 4. Chains of hydrogen-bonded molecules along the c-axis interact in the b direction to form layers parallel to the bc plane.
- Miro Vera, Aira,Velasquez, William,Briceno, Alexander,Bahsas, Ali Bahsas,Valero, Belkis Ramirez,Diaz De Delgado, Graciela
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- Optimal Hydrophobicity in Ring-Opening Metathesis Polymerization-Based Protein Mimics Required for siRNA Internalization
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Exploring the role of polymer structure for the internalization of biologically relevant cargo, specifically siRNA, is of critical importance to the development of improved delivery reagents. Herein, we report guanidinium-rich protein transduction domain mimics (PTDMs) based on a ring-opening metathesis polymerization scaffold containing tunable hydrophobic moieties that promote siRNA internalization. Structure-activity relationships using Jurkat T cells and HeLa cells were explored to determine how the length of the hydrophobic block and the hydrophobic side chain compositions of these PTDMs impacted siRNA internalization. To explore the hydrophobic block length, two different series of diblock copolymers were synthesized: one series with symmetric block lengths and one with asymmetric block lengths. At similar cationic block lengths, asymmetric and symmetric PTDMs promoted siRNA internalization in the same percentages of the cell population regardless of the hydrophobic block length; however, with 20 repeat units of cationic charge, the asymmetric block length had greater siRNA internalization, highlighting the nontrivial relationships between hydrophobicity and overall cationic charge. To further probe how the hydrophobic side chains impacted siRNA internalization, an additional series of asymmetric PTDMs was synthesized that featured a fixed hydrophobic block length of five repeat units that contained either dimethyl (dMe), methyl phenyl (MePh), or diphenyl (dPh) side chains and varied cationic block lengths. This series was further expanded to incorporate hydrophobic blocks consisting of diethyl (dEt), diisobutyl (diBu), and dicyclohexyl (dCy) based repeat units to better define the hydrophobic window for which our PTDMs had optimal activity. High-performance liquid chromatography retention times quantified the relative hydrophobicities of the noncationic building blocks. PTDMs containing the MePh, diBu, and dPh hydrophobic blocks were shown to have superior siRNA internalization capabilities compared to their more and less hydrophobic counterparts, demonstrating a critical window of relative hydrophobicity for optimal internalization. This better understanding of how hydrophobicity impacts PTDM-induced internalization efficiencies will help guide the development of future delivery reagents.
- Deronde, Brittany M.,Posey, Nicholas D.,Otter, Ronja,Caffrey, Leah M.,Minter, Lisa M.,Tew, Gregory N.
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- Cyclohexanedicarboxylic acid derivative with bridge ring and pharmaceutical composition and application thereof
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The invention discloses a cyclohexane dicarboxylic acid derivative with a bridged ring represented by general formula (I). The application of the stereoisomers and the pharmaceutically acceptable salts in the preparation of antitumor drugs has obvious inhibition effects on leukemia, liver cancer, lung cancer, gastric cancer and ovarian cancer. The compound disclosed by the invention has high anti-tumor activity, wide anti-tumor spectrum and low toxicity, and is suitable for preparing anti-cancer drugs.
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Paragraph 0081-0083; 0086-0087
(2021/11/10)
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- A new synthon for the synthesis of aminoinositol derivatives
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The regio- and stereoselective synthesis of a new synthon, trans-3,8-dioxatricyclo[3.2.1.02,4]octane-6,7-diamine, from 7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate is reported. Transformation of the acid functionalities to acyl azides followed by Curtius rearrangement gave the corresponding trans-diisocyanate, which was reacted with HCl to produce a trans-diamino compound that is a potentially important synthon for the versatile synthesis of aminocyclitols.
- Cokol, Nalan Korkmaz,Kaya, Serdal,Balci, Metin
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p. 2732 - 2735
(2017/06/23)
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- Palladium-Catalyzed [2+1] Cycloadditions Affording Vinylidenecyclopropanes as Precursors of 7-Membered Carbocycles
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Palladium(II) acetate in association with secondary phosphine oxides provides an efficient catalytic system for [2+1] cycloadditions starting from oxanorbornene derivatives and tertiary propargyl esters giving rise to vinylidenecyclopropanes. This reaction is specific to bidentate phosphinito-phosphinous acid ligands generated from secondary phosphine oxides. The [2+1] cycloaddition was found broad in scope with a high tolerance to various functional groups. Moreover, vinylidenecyclopropanes were straightforwardly converted into oxabicyclo[3.2.1]oct-2-ene derivatives through a palladium-catalyzed ring-expansion. Finally, the oxa bridge cleavage of oxatricyclic compounds yields functionalized 7-membered carbocycles.
- Lepronier, Aymeric,Achard, Thierry,Giordano, Laurent,Tenaglia, Alphonse,Buono, Gerard,Clavier, Herve
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supporting information
p. 631 - 642
(2016/02/27)
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- Synthesis of chiral polyfunctionalised cyclopentanes from the Diels- Alder adduct of furan and maleic anhydride
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Chiral polyfunctionalised cyclopentanes have been readily obtained in ~65% enantiomeric excess via a stereospecific Wagner-Meerwein rearrangement induced by bromination of derivatives of the exo-cis Diels-Alder adduct of furan and maleic anhydride, combined with desymmetrisation of a meso intermediate by pig liver esterase.
- Brown, Richard T.,Jameson, Simon B.,Ouali, Dehimi,Tattersall, Peter I.
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p. 176 - 178
(2007/10/03)
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- 1,2-Thiazines and Related Heterocycles. Part 5. Characterisation of some (N-Sulphinylamino)azines and their Cycloadducts with 1,4-Epoxy-1,4-dihydronaphthalenes and other Dienophiles
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A range of (N-sulphinylamino)azines has been synthesized and characterised, most for the first time.These heterocycles cycloadd as heterodienes to 1,4-epoxy-1,4-dihydronaphthalenes and similar electron-rich dienophiles through the sulphur atom of the sidechain and an ortho position of the azine ring.When the azine is unsymmetrically functionalised the cycloadditions are strongly periselective: 2-(N-sulphinylamino)pyridine reacts at the ring nitrogen, a preference that is not overturned by the introduction of steric hindrance; 3-(N-sulphinylamino)pyridine reacts at C-2 of the azine but addition may be diverted to C-4 by methylation at C-2.Regioselective additions to unsymmetrical dienophiles are also observed.
- Hanson, Peter,Wren, Stephen A. C.
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p. 2089 - 2097
(2007/10/02)
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