STUDIES ON THE SYNTHESIS OF SIALOSIDES AND SIALIC-ACID ANALOGS .2. A SIMPLE PROCEDURE FOR THE SYNTHESIS OF THE METHYL AND BENZYL GLYCOSIDES OF NEU5AC AND 4-EPI-NEU5AC - CONVERSION OF THE BENZYL AND METHYL GLYCOSIDES OF NEU5AC INTO N-TRIFLUOROACETYLNEURAMINIC ACID BENZYL GLYCOSIDES
STUDIES ON THE SYNTHESIS OF SIALOSIDES AND SIALIC-ACID ANALOGS .2. A SIMPLE PROCEDURE FOR THE SYNTHESIS OF THE METHYL AND BENZYL GLYCOSIDES OF NEU5AC AND 4-EPI-NEU5AC - CONVERSION OF THE BENZYL AND METHYL GLYCOSIDES OF NEU5AC INTO N-TRIFLUOROACETYLNEURAMINIC ACID BENZYL GLYCOSIDES
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DOI：
10.1016/s0008-6215(92)84240-s
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发表时间：
1992-12-31
影响因子：
3.1
通讯作者：
BOVIN, NV
中科院分区：
文献类型：
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作者：
BYRAMOVA, NE;TUZIKOV, AB;BOVIN, NV
从Kuhn-Bashang合成Neu 5Ac的反应产物中分离出乙酰化甲酯形式的5-乙酰氨基-3，5-二脱氧-α-和-β-D-甘油基-D-塔罗-2-壬基吡喃糖酸（4-epi-Neu 5Ac）（1和2）。用过量的甲醇处理（5-乙酰氨基-4，7，8，9-四-O-乙酰基-3，5-二脱氧-D-甘油基-D-半乳糖基-2-壬基吡喃糖基溴）奥纳特甲酯（5），得到高产率的甲基糖苷（13和14）的9：1 α，β-混合物。同样，用苄醇，5得到63：32的苄基糖苷的α，β-混合物（17和18）。用过量的苄醇处理（5-乙酰氨基-4，7，8，9-四-O-乙酰基-3，5-二脱氧-β-D-甘油基-D-塔罗-2-壬吡喃糖基溴）奥纳特甲酯（7），得到苄基糖苷（21和22）与5-乙酰氨基-4，7，8，9-四-O-乙酰基-2，6-脱水-3，5-二脱氧-D-甘油基-D-塔罗-壬-2-烯酸甲酯（9）的3 ∶ 1 α，β-混合物。溴化物7在氯仿中与苄醇在碳酸银存在下缩合，得到苄基糖苷与9的7：1 α，β-混合物。通过皂化，然后N-三氟乙酰化，将苄基糖苷17和18转化为它们各自的N-三氟乙酰基衍生物27和28。Neu 5Ac的甲醇解，接着N-三氟乙酰化和O-乙酰化，得到（4，7，8，9-四-O-乙酰基-3，5-二脱氧-5-三氟乙酰氨基-β-D-甘油基-D-半乳糖基-2-吡喃壬糖苷）奥纳特甲酯（30），其通过2-溴（31）转化为苄基糖苷（32和33）。描述了Neu 5Ac和4-epi-Neu 5Ac的被保护的2-卤代衍生物的简化制备。证明了通过溴化氢的作用将神经氨酸甲基糖苷转化为相应的2-溴代衍生物。
From the reaction products of the Kuhn-Bashang synthesis of Neu5Ac, 5-acetamido-3,5-dideoxy-alpha- and -beta-D-glycero-D-talo-2-nonulopyranosonic acid (4-epi-Neu5Ac) were isolated as the acetylated methyl esters (1 and 2). Treatment of methyl (5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-D-galacto-2-nonulopyranosyl bromide)onate (5) with an excess of methanol gave a high yield of a 9:1 alpha,beta-mixture of the methyl glycosides (13 and 14). Likewise, with benzyl alcohol, 5 gave a 63:32 alpha,beta-mixture of the benzyl glycosides (17 and 18). Treatment of methyl (5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-beta-D-glycero-D-talo-2-nonulopyranosyl bromide)onate (7) with an excess of benzyl alcohol gave a 3:1 alpha,beta-mixture of the benzyl glycosides (21 and 22) together with methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-2,6-anhydro-3,5-dideoxy-D-glycero-D-talo-non-2-enonate (9). Condensation of bromide 7 in chloroform with benzyl alcohol in the presence of silver carbonate afforded a 7:1 alpha,beta-mixture of benzyl glycosides together with 9. The benzyl glycosides 17 and 18 were converted into their respective N-trifluoroacetyl derivatives 27 and 28 by saponification and then N-trifluoroacetylation. Methanolysis of Neu5Ac followed by N-trifluoroacetylation and O-acetylation afforded methyl (methyl 4,7,8,9-tetra-O-acetyl-3,5-dideoxy-5-trifluoroacetamido-beta-D-glycero-D-galacto-2-nonulopyranosid)onate (30), which was converted into the benzyl glycosides (32 and 33) via the 2-bromide (31). A simplified preparation of the protected 2-halogeno derivatives of Neu5Ac and 4-epi-Neu5Ac is described. The conversion of neuraminic acid methyl glycoside into the corresponding 2-bromide derivative by the action of hydrogen bromide is demonstrated.