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1, 3- Dipolar Cycloaddition Reactions of Azomethine Ylides of Ninhydrin with Chalcones and Investigation of Asymmetric Addition of TMSCN to Imines

Assempour, Nazanin | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39951 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Saidi, Mohammad Reza; Jadidi, Khosrow; Mehrdad, Morteza
  7. Abstract:
  8. Part 1
    1,3-dipolar cycloaddition reactions offer convenient routes for the construction of a variety of five-membered heterocycles. This thesis represents a simple synthetic method via 1,3-dipolar cycloaddition reaction to prepare a novel class of spiro pyrrolidines and spiro pyrrolizidines which exhibit many biological activities. Non-stabilized azomethine ylides which generated in situ by the decarboxylative condensation of ninhydrin with proline and sarcosine were used as a 1,3-dipoles. On the other hand, chalcone and its derivatives with an impressive array of pharmacological activities were the dipolarophiles in these reactions. The reactions were carried out through reflax condition and the products were obtained during short time with high yields and stereoselectivity. The structures of products were determined by IR and NMR spectroscopy and the stereoselectivity and the mechanism of the reaction were investigated.
    Part 2
    The Strecker reaction is one of the most efficient and straightforward methods for the synthesis of α-aminonitriles which are very useful precursors for the synthesis of α-amino acids. α-amino acids are of great biological importance due to their significance in chemistry and biology. The classical Strecker reaction is generally carries out by nucleophilic addition of cyanide ion to imines using different Lewis acid or Lewis base catalysts. The asymmetric Strecker reaction is one of the most important methods for the synthesis on enantiomerically pure α-amino acids. A variety of chiral catalysts has been developed to achieve high asymmetric induction for addition of cyanide to imines. In this part of thesis, asymmetric addition of TMSCN to imines of benzaldehydes in the presence of lithium perchlorate as Lewis acid and (2S, 3S)-diethyl tartrate and cinchonidine as chiral catalysts was studied. These investigations demonstrated that in the presence of (2S, 3S)-diethyl tartrate the addition of cyanide ion to imine does not occurred and the reaction with cinchonidine proceeds with no asymmetric induction. At the other section of this thesis, in other to addition of TMSCN to imines of Isatins, several catalysts such as lithium perchlorate, aluminum oxide, aluminum chloride and alum, and a series of solvents including dichloromethane, toluene and acetonitrile were examined. The results showed that under employed conditions the cyanide ion is not able to attack to this imine and with the use these catalyst systems nocleophilic addition of TMSCN to imines of isatins does not occur.


  9. Keywords:
  10. Chalcones ; Strecker Reaction ; Imines ; 1,3-Dipolar-Cycloaddition Reaction ; Azomethine Ylide ; Chiral Catalyst

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