A new glycosylation method part 3: study of microwave effects at low temperatures to control reaction pathways and reduce byproducts

详细信息    查看全文

• 作者：Hiroki Shimizu ; Yayoi Yoshimura ; Hiroshi Hinou ; Shin-Ichiro Nishimura
• 关键词：Microwave ; Nonthermal effect ; Glycosylation ; Carbohydrate
• 刊名：Tetrahedron
• 出版年：2008
• 出版时间：20 October 2008
• 年：2008
• 卷：64
• 期：43
• 页码：10091-10096
• 全文大小：331 K

文摘

The efficiency of microwave irradiation at low temperature for glycosylations is described. Although oligosaccharide synthesis usually requires reactive donors for glycosylations, which have leaving groups on the anomer positions, i.e., trichloroacetoimidates, halogenates, thioalkyl glycosides, etc., the suitable donors in our microwave supported synthesis of Lewis X oligosaccharide were very stable acetate derivatives. Regarding glycosylation with a fucosyl acetate donor and a glucosamine acceptor, microwave irradiation with simultaneous cooling improved yields. Moreover, further synthesis to Lewis X derivatives was achieved only with microwave irradiation at low temperatures. Without microwave irradiation, we could only obtain byproducts and none of the designed product at any reaction temperature.