Synthesis of carboxyl-reduced analogues related to the Chlamydia-specific Kdo trisaccharide epitope
1994; Elsevier BV; Volume: 262; Issue: 2 Linguagem: Inglês
10.1016/0008-6215(94)84181-0
ISSN1873-426X
AutoresFrancis D’Souza, Paul Kosma, Helmut Brade,
Tópico(s)Reproductive tract infections research
ResumoThe disaccharides allyl O-(sodium 3-deoxy-α-d-manno-2-octulopyranosylonate)-(2 → 4)-3-deoxy-α-d-manno-2-octulopyranoside (8), allyl O-(3-deoxy-α-d-manno-2-octulopyranosyl)-(2 → 8)-(sodium 3-deoxy-α-d-manno-2-octulopyranosidonate) (24), and allyl O-(sodium 3-deoxy-α-d-manno-2-octulopyranosylonate)-(2 → 8)-3-deoxy-α-d-manno-2-octulopyranoside (35), and the trisaccharides allyl O-(sodium 3-deoxy-α-d-manno-2-octulopyranosylonate)-(2 → 8)-(sodium 3-deoxy-α-d-manno-2-octulopyranosylonate)-(2 → 4)-3-deoxy-α-d-manno-2-octulopyranoside (13) and allyl O-(3-deoxy-α-d-manno-2-octulopyranosyl)-(2 → 8)-(sodium 3-deoxy-α-d-manno-2-octulopyranosylonate)-(2 → 4)-(sodium 3-deoxy-α-d-manno-2-octulopyranosidonate) (30) were prepared. The ketosidic linkages were formed in good yields and high stereoselectivity by BF3 · Et2O-catalyzed reaction of the per-O-acetylated 3-deoxy-α-d-manno-2-octulopyranosyl fluoride derivative (16) with 8-O-SiButMe2 derivatives 19 and 21. Coupling reactions using the Kdo monosaccharide bromide derivative 4 or the α-(2 → 8)-linked Kdo disaccharide bromide derivatives 9 and 26 were performed under Helferich conditions in MeCN or MeNO2, respectively. The disaccharide halides were prepared in good overall yields starting from the readily available allyl β-glycoside of Kdo. The deprotected oligosaccharides correspond to the genus-specific lipopolysaccharide epitope of Chlamydia and part structures thereof, containing the carboxyl-reduced Kdo-residues at the distal and proximal position of the Kdo trisaccharide epitope, respectively.
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