Carbohydrate conjugates complex

The following method for carbohydrate conjugation to dendrimers may be used to couple a variety of reducing sugars to amine-dendrimers, including saccharides, longer-chain carbohydrates, and even complex glycans after release from a protein (see Chapter 1, Section 4.6). 

Several combinatorial approaches for the synthesis of glyco-amino acids have been developed, due to the complexity of carbohydrate conjugates. The synthetic challenge is to get access to these building blocks by automated synthesis in order to generate glycopeptides library, to fully understand their biological roles and to widen their use in medicinal chemistry. 

Bob s research interests and knowledge across chemistry were great. Throughout his career he retained an interest in biomimetic chemistry, specifically the study of metal ion-promoted reactions and reactions of molecules activated by metal ion coordination. His early interests in carbohydrate chemistry inspired him to study metal ion catalysis of both peptide formation and hydrolysis as well as studies in inorganic reaction mechanisms. He was particularly interested in the mechanisms of base-catalyzed hydrolysis within metal complexes and the development of the so-called dissociative conjugate-base (DCB) mechanism for base-catalyzed substitution reactions at inert d6 metal ions such as Co(III). 

This report was the first of its type to show the ability of such a large covalently linked carbohydrate (neomycin) to aid in RNA-DNA hybrid complex-ation. N-Neo-conjugate and a 7-base-long RNA sequence present in a-sarcin loop can form a stable hybrid duplex. The stability of a hybrid duplex with addition of one neomycin equivalent is comparable to the stability of a hybrid duplex where the DNA has a covalent bond to neomycin. The presence of a single mismatch decreases the melting temperature of both neomycin-conjugated... 

To facilitate accesses to suitably functionalized sialic acid derivatives and complex sialyloligosaccharides for other usehil neoglycoconjugates, phase transfer catalysis (PTC) has been exploited extensively [for reviews see 42]. This process provided a wide range of carbohydrate derivatives under essentially clean Sn2 transformations. In the case of acetochloroneuraminic acid 1, the PTC reactions always provided inverted a-sialic acid derivatives [43]. para-Formylphenyl sialoside 7 [44], together with many other sialoside derivatives such as 8-10 [43], including thioacetate 12 [45] and azide 14 [46], were thus obtained (Scheme 1). Aldehyde 7 and similar glycosides are of particular interest since they could be directly conjugated to protein by reductive amina-tion after suitable deprotection [44]. 

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