Sökning: "furanosides"

Hittade 5 avhandlingar innehållade ordet furanosides.

  1. 1. Lewis acid promoted endocyclic cleavage of glycosides and related acetals

    Författare :Roger Olsson; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; halichomycin; allylation; carbene; hydrogen bond; organozinc; organotitanium; furanosides; organoaluminium; pyranosides; glycosides; stereoselective; endocyclic cleavage; nucleophilic ring opening; ab initio; Organic chemistry; Organisk kemi;

    Sammanfattning : This thesis is a summary of five papers concerning endocyclic cleavage of glycosides and related acetals. Simple lactol ethers undergo endocyclic cleavage to give acyclic chain extended products on treatment with organoaluminium and organotitanium reagents. LÄS MER

  2. 2. Studies of the anomeric center : mechanism and synthesis

    Författare :Karl-Jonas Johansson; Harri Lönnberg; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Organic Chemistry; organisk kemi;

    Sammanfattning : This thesis is based on three publications and one appendix and is divided into two parts. The first part is a mechanistic study of the anomerization reaction of both aldo and keto glycosides and the second part is a synthetic study of a unusual type of glycosidic linker found in the lipopolysaccharide core Proteus Mirabilis 0270. LÄS MER

  3. 3. Synthesis and Rearrangement of Epoxy Sugars

    Författare :Fritiof Pontén; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Organisk kemi; Organic chemistry; crown ether; silica; Intramoleculaf Diels-Alder reaction; radical allylation; allyl sulfone; sugar epoxide; allyl sulfide; ring-contraction; C-glycoside; a; IMDAF; b-unsaturated aldehyde;

    Sammanfattning : Ring-Contraction of sugar-derived epoxy alcohols, functionalised in position 1 and 6, by treatment with lithium bromide and N, N, N', N'-tetramethylurea in refluxing toluene gave enantiomerically pure a,b-unsaturated aldehydes of furanosides. O-Glycosidic epoxy alcohols gave only one, easily purified, aldehyde in approximately 30-60% yield depending on the substitution pattern. LÄS MER

  4. 4. Mechanism Studies of Catalytic RNA, and RNA and DNA Model Compounds

    Författare :Ethel Pettersson; Eric Westhof; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Organic Chemistry; organisk kemi;

    Sammanfattning : This thesis describes mechanism studies of transesterifications of phosphate esters. The aim of the studies concerns two fields. First, the catalytic mechanism that group I introns use in self-splicing. The focus was on metal ion coordinating groups at the catalytic site. LÄS MER

  5. 5. Studies on phosphate ester cleavage and development of oligonucleotide based artificial nucleases (OBAN´s)

    Författare :Hans Åström; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP;

    Sammanfattning : Five different Oligonucleotide Based Artificial Nuclease (OBAN) systems have been synthesized. OBAN's may be regarded as a development of traditional antisense methodology where inhibition of gene expression can be achieved by hybridizing a synthetic oligonucleotide to natural mRNA and thus inhibiting further translation into protein products. LÄS MER