APPROACHES TO CARBOCYCLIC ANALOGS OF THE POTENT NEURAMINIDASE INHIBITOR 4-GUANIDINO-NEU5AC2EN - X-RAY MOLECULAR-STRUCTURE OF N-[(1S,2S,6R)-2-AZIDO-6-BENZYLOXYMETHYL-4-FORMYLCYCLOHEX-3-ENYL]ACETAMIDE

Various approaches using Diels-Alder chemistry have been established for the synthesis of truncated carbo cyclic analogues 4 and 6 of 4-guanidino-Neu5Ac2en. In the case of compound 4, elaboration of an initial adduct from Danishefsky's diene and the dienophile 7 allowed access to the key enone 26. Methylenation of the carbonyl group and azide-induced opening of an intermediate oxazoline established the required framework regio- and stereo-specifically. Compounds 4 and 6 were found to retain interesting levels of antiviral activity comparable to those shown by their oxygen-containing counterparts.