Patent ID: 7214794

Claim:
Compounds of general formula (I) where X 1 and X 2 are selected between O and S; R 1 and R 2 are selected between —(CH 2 ) 13 CH 3 and alkyl or alkylene groups with from 2 to 6 carbon atoms, linear or branching, unsubstituted or substituted with one or more substituents selected among aromatic, primary, secondary and tertiary aminic, quaternary ammonium, carboxylic, hydroxylic, polyoxyalkyl and ethereal groups, amino acids, halogen atoms or saccharides, providing that between R 1 and R 2 only one is always —(CH 2 ) 13 CH 3 , R 3 and R 4 are selected between H and alkyl or alkylene groups with from 2 to 6 carbon atoms, linear or branching, unsubstituted or substituted with one or more substituents selected among aromatic, primary, secondary and tertiary aminic, quaternary ammonium, carboxylic, hydroxylic, polyoxyalkyl and ethereal groups, amino acids, halogen atoms or saccharides.