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  • Open access
  • 54 Reads
Stereospecific Synthesis of cis and trans 1-Oxabicyclo[4,4,0]decanes and 9-Methoxycarbonyl-1-oxabicyclo[4,3,0]nonanes
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2-(2'-Phenylsulphinylprop-2'-enyl)cyclohexanone (3) and 2-ethoxycarbonyl-2-(2'-phenylsulphinylprop-2'-enyl) cyclopentanone(12) derived from 2-phenylsulphinyl-3--toluenesulphonyloxyprop-1-ene (1) and 2-phenylsulphinyl-3-methanesulphonyloxyprop-1-ene (10) by reaction with 1-pyrroridinylcyclohexene (2) and 2-ethoxycarbonyl cyclopentanone (11) respectively, were reduced with sodium borohydride to afford in each case a racemic mixture of four isomeric hydroxy alkenyl sulphoxides that on oxidation produced in each case two hydroxy alkenyl sulphones cis (4),(13) and trans (5),(14) which separated by column chromatography. Treatment of the hydroxy alkenyl sulphones (4),(5),(13) and (14) with a molar equivalent of base yielded the corresponding 3-phenylsulphonyl cyclic adducts (6),(7),(15) and (16) respectively that were reduced with Raney nickel to afford the requisite cis and trans 1-oxabicyclo4,4,0decanes (8) and (9) and 9-methoxycarbonyl-1-oxabicyclo4,3,0nonanes (17) and (18) in good yields.
  • Open access
  • 39 Reads
Synthesis of Novel Hydroxylamino Carbonic Acid Structures
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Synthetic routes to various types of novel O-(-aminoalkyl) substituted hydroxylamino carbonic acid derivatives have been elaborated. Some of the new compounds exhibited significant cardiovascular or CNS activity, and induced the cellular heat shock protein synthesis in vitro and in vivo
  • Open access
  • 45 Reads
Intramolecular Cycloaddition of Imines of Cysteine Derivatives
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The intramolecular 1,3-dipolar cycloaddition is an important method for the construction of ring fused heterocycles. The prototropic generation of azomethine ylides from imines of a-amino acids esters is an example of this type of process.[1] We have previously reported the synthesis of tetrahydro-1H-thieno[3,4-b]pyrrole 2 through an intramolecular 1,3-dipolar cycloaddition of the azomethine ylide which was generated from the Schiff base 1 by proton transfer.[2] The structure of compound 2 was established by X-ray crystallography. Grigg and colleagues have also reported two examples of intramolecular dipolar cycloaddition of azomethine ylides derived from Schiff bases of S-allylcysteine methyl ester.1 We decided to further study this cycloaddition reaction in order to extend it as a methodology of synthesis of thieno[3,4-b]pyrrole derivatives.
  • Open access
  • 67 Reads
Total Synthesis of Morphine- and Hasubanane Alkaloids
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(-)-Morphine, the main alkaloid of the opium poppy, remains one of the most important medicines for the treatment of severe pain and a true delight for synthetic chemists.1 In spite of its small size and long history, it is still considered to be an interesting target for chemical synthesis. (-)-Morphine and its synthetic precursors (-)-codeine and (-)-dihydrocodeinone feature a complicated network of three carbocycles and two heterocycles containing five vicinal stereocenters, four of which define ring junctures. Among these, the benzylic quaternary carbon deserves special attention.
  • Open access
  • 50 Reads
Synthesis of Aromatic Ethers under Microwave Irradiation in Dry Media
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Under microwave irradiation a number of phenols react remarkably fast with a number of primary alkyl halides to give aromatic ethers. The procedure is alternative to those which rely on the use of dipolar aprotic solvents, sodium, sodium hydride, sodium amide and several procedure that rely on "standard" PTC methods
  • Open access
  • 33 Reads
Efficient Polymer-supported Sharpless Alkene Epoxidation Catalyst
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Over the past years a great deal of interest has been focused on organic reactions performed in the presence of functional polymers acting either as reagents or catalysts. The effective immobilisation of asymmetric catalysts, reagents and auxiliares is a particularly important methodological target, especially for metal complex-based catalysts
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