Compounds of formula: Wherein X 1 and X 2, the same or different, are CH, CH 2 the bond between X 1 and X 2 may be satured or unsatured X 3 and X 4 are the same and are S n is an integer comprised between 1 and 10 R is H, alkyl selected from the group consisting of: methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, sec-butyl optionally substituted with a group selected from the group consisting of: adamantyl, i-propyl, sec-butyl, i-butyl, tert-butyl, i-pentyl, hydroxymethyl, 1-hydroxyethyl, sulfanylmethyl, 2-(methylsulfanyl)ethyl, carboxymethyl, carboxyethyl, 4-aminobutyl, 2-carbamoylethyl, 2-carbamoylmethyl, 2-methyl-3H-imidazole, 3-methyl-1H-indole, alkenyl selected from the group consisting of: ethenyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, isopentenyl, geranyl, farnesyl optionally substituted with a group selected from the group consisting of: ethenyl, 2-propenyl, isopentenyl, geranyl, farnesyl, aryl optionally substituted with a group selected from the group consisting of: benzyl, 4-hydroxybenzyl, 3-alkyl-1H-indole, 2-methyl-1H-imidazole, 3,4-dihydroxyphenyl-methyl, 4-(2-aminoethyl)benzene-1,2-diol, 4-hydroxy-3methyl-phenylmethyl, 4-hydroxy-3-isopropyl-phenyl-methyl, 3,4-dihydroxy-phenyl-ethyl, (3,4-dihydroxy-phenyl)-2-hydroxyethyl, (5-hydroxy-1H-indol-3-yl)ethyl, cyclic compounds having one or more cycles, consisting of a number of carbon atoms p comprised between 1 and 10, optionally substituted, R 1 and R 2, the same or different, are H, CH 3, alkyl, alkenyl, aryl or R1 are R 2 in a cyclic compound having one or more cycles, consisting of a number of carbon atoms m comprised between 1 and 10, optionally substituted, their stereoisomers, enantiomers, conformers and racemic mixture of different stereoisomers. X 1 and X 2, the same or different, are CH, CH 2 the bond between X 1 and X 2 may be satured or unsatured X 3 and X 4 are the same and are S n is an integer comprised between 1 and 10 R is H, alkyl selected from the group consisting of: methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, sec-butyl optionally substituted with a group selected from the group consisting of: adamantyl, i-propyl, sec-butyl, i-butyl, tert-butyl, i-pentyl, hydroxymethyl, 1-hydroxyethyl, sulfanylmethyl, 2-(methylsulfanyl)ethyl, carboxymethyl, carboxyethyl, 4-aminobutyl, 2-carbamoylethyl, 2-carbamoylmethyl, 2-methyl-3H-imidazole, 3-methyl-1H-indole, alkenyl selected from the group consisting of: ethenyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, isopentenyl, geranyl, farnesyl optionally substituted with a group selected from the group consisting of: ethenyl, 2-propenyl, isopentenyl, geranyl, farnesyl, aryl optionally substituted with a group selected from the group consisting of: benzyl, 4-hydroxybenzyl, 3-alkyl-1H-indole, 2-methyl-1H-imidazole, 3,4-dihydroxyphenyl-methyl, 4-(2-aminoethyl)benzene-1,2-diol, 4-hydroxy-3methyl-phenylmethyl, 4-hydroxy-3-isopropyl-phenyl-methyl, 3,4-dihydroxy-phenyl-ethyl, (3,4-dihydroxy-phenyl)-2-hydroxyethyl, (5-hydroxy-1H-indol-3-yl)ethyl, cyclic compounds having one or more cycles, consisting of a number of carbon atoms p comprised between 1 and 10, optionally substituted, R 1 and R 2, the same or different, are H, CH 3, alkyl, alkenyl, aryl or R1 are R 2 in a cyclic compound having one or more cycles, consisting of a number of carbon atoms m comprised between 1 and 10, optionally substituted, their stereoisomers, enantiomers, conformers and racemic mixture of different stereoisomers.