The Isothiocyanato Moiety: An Ideal Protecting Group for the Stereoselective Synthesis of Sialic Acid Glycosides and Subsequent Diversification
| Autor: | Appi Reddy Mandhapati, David Crich, Jonathan G. Shaw, Salla Rajender |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Trimethylsilyl
Thiourea Stereoisomerism General Chemistry General Medicine Silanes Combinatorial chemistry Catalysis N-Acetylneuraminic Acid Article chemistry.chemical_compound chemistry Deamination Isothiocyanate Organic chemistry Moiety Amine gas treating Stereoselectivity Glycosides Guanidine Protecting group Thiocyanates |
| Zdroj: | Angewandte Chemie. 127:1291-1294 |
| ISSN: | 0044-8249 |
| DOI: | 10.1002/ange.201409797 |
| Popis: | The preparation of a crystalline, peracetyl adamantanyl thiosialoside donor protected by an isothiocyanate group is described. On activation at -78 C in the presence of typical carbohydrate acceptors this donor gives high yields of the corresponding sialosides with exquisite α-selectivity. The high selectivity extends to the 4-O-benzyl-protected 3-OH acceptors that are typically less reactive and selective than galactose 3,4-diols. Treatment of the α-sialosides with tris(trimethylsilyl)silane or allyltris(trimethylsilyl)silane sialosides replaces the C5-N5 bond by a C-H or a C-C bond. Reaction of the isothiocyanate-protected sialosides with thioacids achieves conversion into amides. Reaction of the isothiocyanate with an amine gives a thiourea, which can be converted to a guanidine. The very high α-selectivities observed with the new donor and the rich chemistry of the isothiocyante function considerably extend the scope for optimization at the sialoside 5-position. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text