Uronosyl phosphonate-based sialidase inhibitor synthesis and conformational analysis
摘要:
With a view to development of novel sialidase inhibitors, mimetics of the natural inhibitor Neu5Ac2en have been prepared in which a phosphonate group replaces the sialic acid glycerol side chain. Different hex-4-en derivatives adopt half-chair conformations that place the glycosyl phosphonate in an equatorial position. For the alpha-L-threo-hex-4-en derivative this conformation is equivalent to that of Neu5Ac2en, and opposite to that seen for alkyl O-glycosides with the same overall stereochemistry. (C) 2012 Elsevier Ltd. All rights reserved.
Accessing C-1 Phosphonylated 2-Acylamino Uronic Acids via 2-Nitro-glycals
摘要:
Two approaches are described for the synthesis of 2-acylamino uronic acid glycosyl phosphonates from readily accessible D-glucal. The first approach that entailed oxidation of the C-6 hydroxyl group followed by phosphonylation of the uronate 2-nitro-glycal, resulted in the formation of the beta-L-gulo-configured phosphonate. Reversing the reaction order resulted in the exclusive formation of the beta-D-gluco-configured phosphonate. In both cases the thermodynamic 1,2-trans-di-equatorial phosphonylation product is obtained.