Synthesis of Fluorescent 4-Methyl-7-thiocoumaryl S-Glycosides of Sialic Acid.
作者:Makoto TANAKA、Toshitsugu KAI、Xue-Long SUN、Hiroaki TAKAYANAGI、Yutaka UDA、Kimio FURUHATA
DOI:10.1248/cpb.43.1844
日期:——
Condensation of 4-methyl-7-thiocoumarin sodium salt with methyl 5-N-acetyl-4, 7, 8, 9-tetra-O-acetyl-2-chloro-2, 3, 5-trideoxy-D-glycero-D-galacto-2-nonulopyranosonate (2), methyl 5-N-(O-acetylglycolyl)-4, 7, 8, 9-tetra-O-acetyl-2-chloro-2, 3, 6-trideoxy-D-glycero-D-galacto-2-nonulopyranosonate (11), and methyl 4, 5, 7, 8, 9-penta-O-acetyl-2-chloro-2, 3-dideoxy-D-glycero-D-galacto-2-nonulopyranosonate (14) under Williamson reaction conditions gave the corresponding α-glycosides in good yields. Deprotection of these α-glycosides gave three new fluorogenic substrates, the 4-methylcoumarin-7-yl S-glycosides of N-acetylneuraminic acid, N-glycolylneuraminic acid, and 3-deoxy-D-glucose-D-galacto-2-nonulopyranosonic acid (KDN). Furthermore, we have developed a facile method for preparation of benzyl 5-amino-3, 5-dideoxy-α-D-glycero-D-galacto-2-nonulopyranosidonic acid (7), a key intermediate for the synthesis of N-glycolylneuraminic acid.
4-甲基-7-硫代香豆素钠盐与 5-N-乙酰基-4,7,8,9-O-四乙酰基-2-氯-2,3,5-三脱氧-D-甘油-D-半乳-2-壬磺吡喃糖酸甲酯 (2)、5-N-(O-乙酰基甘氨酰)-4,7,8,9-O-四乙酰基-2-氯-2,3,6-三脱氧-D-甘油-D-半乳-2-壬磺吡喃糖酸甲酯 (11) 和 4,5,7,8,9-O-五乙酰基-2-氯-2-壬磺吡喃糖酸甲酯的缩合在威廉姆森反应条件下,5-N-(O-乙酰基甘氨酰)-4,7,8,9-四-O-乙酰基-2-氯-2,3,6-三脱氧-D-甘油-D-半乳糖-2-壬磺吡喃糖酸甲酯(11)和 4,5,7,8,9-五-O-乙酰基-2-氯-2,3-二脱氧-D-甘油-D-半乳糖-2-壬磺吡喃糖酸甲酯(14)以良好的产率得到了相应的 α-糖苷。对这些 α-糖苷进行脱保护处理,可得到三种新的含氟底物,即 N-乙酰神经氨酸、N-乙酰神经氨酸和 3-脱氧-D-葡萄糖-D-半乳糖-2-壬磺吡喃糖酸(KDN)的 4-甲基香豆素-7-基 S-糖苷。此外,我们还开发了一种简便的方法来制备 5-氨基-3,5-二脱氧-α-D-甘油-D-半乳糖-2-壬磺吡喃糖酸苄酯 (7),这是合成 N-乙酰神经氨酸的关键中间体。