Compounds exhibiting antiviral activity and/or inhibition of viral replication against viruses, particularly those belonging to the picornavirus-like supercluster, including coronavirus having a formula: (I) where X comprises a cyclic moiety, R is a branched or unbranched alkyl, cycloalkyl, aryl, arylalkyl, alkenyl, alkynyl, amino acid side chain, bicyclic or tricyclic side chain, combinations, and substituted forms thereof, and Z is selected from the group consisting of C-C hydroxyalkyl, aldehydes, alpha-ketoamides, and bisulfite salts, and in particular -CHOH, -CHO, -CH(0H)S0Na, and -[0(C=0)R]S0Na.