R1, R2 and R3 independently represent an alkyl radical C1-C6, (substituted or not), a phenyl group or aromatic ring with one or more heteroatoms, and substituted by groups of hdyroxyl, methoxy, trifluoromethyl, nitro, cyano, carbaldehyde, carboxylic, carboxylic ester, halogen or alkyl radical C1-C6 (substituted or not) and that are found in positions C2' 3' or 4' of the benzene ring or are heterocyclic with five or six links, such as furane, thiophene, pyrrole, pyridine, pyracin, pyradazine, pyramidine or indole.
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