D'Souza F W, Kosma P, Brade H
Institut für Chemie, Universität für Bodenkultur, Wien, Austria.
Carbohydr Res. 1994 Sep 15;262(2):223-44. doi: 10.1016/0008-6215(94)84181-0.
The disaccharides allyl O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->4)-3-deoxy-a lph a-D- manno-2-octulopyranoside (8), allyl O-(3-deoxy-alpha-D-manno-2-octulopyranosyl)-(2-->8)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosidonate) (24), and allyl O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->8)-3-deoxy-a lph a-D- manno-2-octulopyranoside (35), and the trisaccharides allyl O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->8)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->4)-3-deoxy-a lph a-D-manno-2-octulopyranoside (13) and allyl O-(3-deoxy-alpha-D-manno-2-octulopyranosyl)-(2-->8)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->4)-(sodium 3-deoxy-alpha-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-alpha-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 alpha-(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 beta-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.
制备了二糖烯丙基O -（3 - 脱氧-α-D-甘露-2-辛酮糖醛酸酯钠）-（2→4）-3 - 脱氧-α-D-甘露-2-辛酮糖苷（8）、烯丙基O -（3 - 脱氧-α-D-甘露-2-辛酮糖基）-（2→8）-（3 - 脱氧-α-D-甘露-2-辛酮糖醛酸酯钠）（24）和烯丙基O -（3 - 脱氧-α-D-甘露-2-辛酮糖醛酸酯钠）-（2→8）-3 - 脱氧-α-D-甘露-2-辛酮糖苷（35），以及三糖烯丙基O -（3 - 脱氧-α-D-甘露-2-辛酮糖醛酸酯钠）-（2→8）-（3 - 脱氧-α-D-甘露-2-辛酮糖醛酸酯钠）-（2→4）-3 - 脱氧-α-D-甘露-2-辛酮糖苷（13）和烯丙基O -（3 - 脱氧-α-D-甘露-2-辛酮糖基）-（2→8）-（3 - 脱氧-α-D-甘露-2-辛酮糖醛酸酯钠）-（2→4）-（3 - 脱氧-α-D-甘露-2-辛酮糖醛酸酯钠）（30）。通过BF₃·Et₂O催化全-O-乙酰化的3 - 脱氧-α-D-甘露-2-辛酮糖基氟衍生物（16）与8 - O - SiButMe₂衍生物19和21反应，以良好的产率和高立体选择性形成酮糖苷键。分别在MeCN或MeNO₂中，在Helferich条件下使用Kdo单糖溴化物衍生物4或α-（2→8）连接的Kdo二糖溴化物衍生物9和26进行偶联反应。二糖卤化物从易于获得的Kdo烯丙基β-糖苷开始制备，总产率良好。脱保护的寡糖对应于衣原体属特异性脂多糖表位及其部分结构，分别在Kdo三糖表位的远端和近端位置含有羧基还原的Kdo残基。
