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Title: Studies towards the synthesis of few biologically active chiral(Gama)-butyrolactone based molecules employing 2-hydroxycitric acid lactones
Researcher: Thomas, Salini
Guide(s): Saud, I Ibnu
Upload Date: 6-Aug-2010
University: Mahatma Gandhi University
Completed Date: January 2006
Abstract: (2S, 3s) and (2S,3R)-tetrahydro-3-hydroxy-5-oxo-2,3-furandicarboxylic acids (Garcinia and Hibiscus acids) have been isolated form plant sources in large amounts. Several attempts were made for the reduction of carboxyiate functional groups, often selectively, using various borane reagents namely BH3THF, BH3SMe2. BH3/trimethyl borate,NaBH4/12 etc. Selective reduction of ester group geminal to hydroxyl group in methyl (2S, 3s)- tetrahydro-3-hydroxy- 5-0x0-2,3-furandicarboxylate, using borane dimehtyl sulphide and catalytic amount of sodium borohydride resulted in (25 3R)-terahydro-3-hydroxy-3-(hydroxymethyl)- 5-0x0-2-furancarboxylate. a versatile ch~ron. Subsequently the diol obtained was converted to analogue of (+)- avenaciolide ((3aR. 6aS)-3a-hydroxytetrahydrofuro [3, 4-blfuran-2.6-dione], a biologically significant bislactone skeleton using ptoluene sulphonic acid. Attempts were made to convert (2S, 3R)-terahydro-3-hydroxy-3- (hydroxymethy1)-5-0x0-2-furancarboxylate to analogues of CIS-whisky and cognac lactones. Interestingly much selectivity was not observed in the case of (2S, 3R)- tetrahydro-3-hydroxy-5-0x0-2, 3-furandicarboxylic acid when reduced using borane dimehtylsulphide and catalytic amount of sodium borohydride. The observed difference in reactivity of the said reagent towards methyl (2S, 3s) and (2S, 3R)- etrahydro-3-hydroxy-5-0x0-2.3-furandicaoate have been analysed mechanistically. Starting with Garcinia acid functionalized chiral butenolides, structural motifs useful for the synthesis of a variety of biologically interesting molecules bearing 2(5H) furanone subunits, have been prepared. The trialkyl (IS, 25) and (IS, 2R)- 1. 2-dihydroxy-I, 2, 3-propanetricarboxylates obtained from the title acids have been effectively employed as chiral ligands in Sharpless asymmetric epoxidation and sulphoxidation reactions.
Pagination: v, 201p.
Appears in Departments:School Of Chemical Science

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02_certificate.pdf19.23 kBAdobe PDFView/Open
03_declaration.pdf17.89 kBAdobe PDFView/Open
04_acknowledgement.pdf54.41 kBAdobe PDFView/Open
05_content.pdf84.13 kBAdobe PDFView/Open
06_list of publication.pdf35.31 kBAdobe PDFView/Open
07_abstract.pdf36.13 kBAdobe PDFView/Open
08_chapter1.pdf656.8 kBAdobe PDFView/Open
09_chapter2.pdf1.34 MBAdobe PDFView/Open
10_chapter3.pdf434.21 kBAdobe PDFView/Open
11_chapter4.pdf549.81 kBAdobe PDFView/Open
12_chapter5.pdf153.78 kBAdobe PDFView/Open
13_references.pdf211.17 kBAdobe PDFView/Open

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