Neu5Ac2en, analogues structure

A number of C-6 carboxamide analogues were prepared in which the stereo-chemically complex glycerol side-chain of Zanamivir or 4-amino-4-deoxy-Neu5Ac2en was replaced entirely by secondary or tertiary amides with the general structure of 94 or 95.95,96 These series of compounds were prepared from the C-6 carboxylate 92 (prepared by periodate oxidation of the glycerol side-chain of 91) by amide couling via the activated pentafluorophenyl ester 93 (Scheme 3). 

Chandler, M. et al. Approaches to Carbocyclic Analogues of the Potent Neuraminidase Inhibitor 4-Guanidino-Neu5Ac2en. X-Ray Molecular Structure of N-[(/ S,2S, 6R)-2-azido-6-benzyloxy-methyl-4-formylcyclohex-3-enyl]acetamide. 3.4.1 1995 [112]... 

The discovery, in the early 1990s, that zanamivir was a potent and selective inhibitor of influenza virus sialidase prompted several researchers to investigate the synthesis of Neu5Ac2en based analogues of zanamivir. Much of this effort was a consequence of the fact that zanamivir (12) must be administered as a nasal spray, due to its poor oral bioavailability and rapid excretion [101,102], and the desire to identify new sialidase inhibitors with modified physicochemical properties. Several researchers have described structure-activity relationship studies based on zanamivir (vide infra), with most modifications reported at C-4, C-5, and the glycerol side-chain. 

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