Methods for treating viral infections

A method of treating infection caused by at least one virus of the Flaviviridae family in a living host having said infection, said method comprising administering to said host a therapeutically effective amount of a compound, or a precursor of said compound, having the formula:

• wherein X represents a moiety selected from the group consisting of S, O, or N(Ra), Ra being hydrogen or alkyl of 1-5 carbon atoms;
• R1 represents a radical selected from those consisting of an unsubstituted or substituted heterocyclic group, an unsubstituted or substituted bicyclic ring moiety, an unsubstituted or substituted phenyl (C6H5) group, an unsubstituted or substituted biphenyl (C6H5—C5H4) group, an unsubstituted or substituted w-phenylalkenyl (C6H5(CH═CH)n)group, n being an integer from 1 to 5, an unsubstituted or substituted ω-phenylalkynyl (C6H5(C═C)p) group, p being an integer from 1 to 5 or an unsubstituted or substituted alkyl group of 1-5 carbon atoms, which may be straight or branched chain, said heterocyclic group being selected from those consisting of furan, thiophene, oxazole, oxadiazole, pyridine, pyrimidine, pyrazole, triazole, pyridazine, 1,3-oxathiolane, thiazole, thiadiazole, imidazole, pyrrole, tetrazole and triazine, said bicyclic ring moiety being selected from those consisting of benzofuran, isobenzofuran, benzothiophene, isobenzothiophene, benzoxazole, benzopyrrole, isoindole, benzpyrazole, quinoline, isoquinoline, 1,2-benzodiazine, 1,3-benzodiazine, 1,2,3-benzotriazole, benzothiazole, benzimidazole, 1,2,3-benzotriazine and 1,2,4-benzotriazine, the heterocyclic group and bicyclic ring moiety substituents being selected from those consisting of alkyl of 1-5 carbon atoms, halogen, alkoxy, hydroxy, nitro, perhaloalkyl, dihaloalkyl, monohaloalkyl, thio, alkylthio, alkylsulfinyl, alkylsulfonyl or an unsubstituted or substituted phenyl group;
• R2 and R3 independently represent hydrogen, an unsubstituted or substituted phenyl group, or —(CH2)qCOOH, q being an integer from 1-5, and at least one of said R2 and R3 being hydrogen;
• the phenyl group substituents, the biphenyl group substituents, the ω-phenylalkenyl group substituents and the ω-phenylalkynyl group substituents being at least one selected from those consisting of halogen, nitro, carboxy, hydroxy, alkyl of 1-5 carbon atoms, perhaloalkyl, dihaloalkyl, monohaloalkyl, alkoxy, acylocy, cyano, amino, alkylamino, dialkylamino, sulfonamido, carboxamido, carbalkoxy, thio, alkylthio, alkylsulfinyl and alkylsulfonyl;
• the alkyl group substituents being at least one selected from those consisting of carboxy, hydroxy, alkoxy, amino, alkylamino, dialkylamino, thio or alkylthio, and the isomers and pharmaceutically acceptable salts of said compound.