A series of novel 2-(substitutedphenyl)-5-methyl-3-(phenylamino)-1,3-thiazolidin-4-ones (4a-g) were synthesized and structurally confirmed by elemental, IR, 1H NMR and MS spectral analysis. Further, the antiviral screening of 2-(substitutedphenyl)-5-methyl-3-(phenylamino)-1,3-thiazolidin-4-ones (4a-g) against a broad panel of DNA and RNA viral strains indicated that 2-(4-chlorophenyl)-5-methyl-3-(phenylamino)-1,3-thiazolidin-4-one (4a) showed some antiviral activity against herpes simplex virus-1 (KOS) (EC50 = 47 μM), herpes simplex virus-2 (G) (EC50 = 42 μM), herpes simplex virus-1 TK- KOS ACVr (EC50 = 47 μM), vaccinia virus (EC50 = 45 μM) and vesicular stomatitis virus (EC50 = 51 μM) tested in human embryonic lung (HEL) cell cultures. 5-methyl-2-(4-nitrophenyl)-3- (phenylamino)-1,3-thiazolidin-4-one (4g) and 2-(4-bromophenyl)-5-methyl-3-(phenylamino)-1,3-thiazolidin-4-one (4d) showed some antiviral activity against cytomegalovirus [EC50 = 15 and 100 μM (AD-169) and EC50 = 10 and 100 μM (Davis strain), respectively] tested in HEL cell cultures. 2-(4-bromophenyl)-5-methyl-3-(phenylamino)-1,3- thiazolidin-4-one (4d) and 5-methyl-2-(2-nitrophenyl)-3-(phenylamino)-1,3-thiazolidin-4-one (4e) showed antiviral activity against feline corona virus (FIPV) (EC50 = 18 and 41 μM, respectively) tested in Crandell-Rees feline kidney (CRFK) cell cultures and can be considered as lead compounds for the development of novel antiviral agents.
