Semisynthesis is a methodology which uses a substance of natural origin as starting material to carry out structural modifications with the aim of altering its biological properties. Diterpenes are a class of substances that have different biological and pharmacological activities, such as anticancer, anti-inflammatory, antiparasitic, antimicrobial and cardiovascular. Among the ent-kaurane type diterpenes, 3β- hydroxykaurenoic acid is described in the literature with significant cytotoxic, antifungal and antibacterial activity, in addition to promising antimicrobial activity. Thus, 3β- hydroxykaurenoic acid was subjected to structural modifications in order to modulate its biological properties. The 3β-hydroxycaurenoic acid was subjected to chemical modifications using mCPBA for the epoxidation reaction and N-halo-succinimides (NBS, NCS and NIS) for the halogenation reactions. The products obtained from each reaction were subjected to preparative thin layer chromatography (TLC) for isolation and purification. By analyzing the mass spectra and the 1H, 13C and DEPT 135 NMR spectra, a mixture of two products was proposed for the epoxidation reaction, a mixture of enantiomers for the bromination reaction, and a mixture of monochlorinated and dichlorinated products for the chlorination reaction. Furthermore, it was not possible to suggest the structure of the products obtained from the iodination reaction, however, the spectral data indicate that the reaction was effective. The results obtained indicate 3β-hydroxykaurenoic acid as a good starting material for semisynthesis reactions, yielding analogous derivatives with potential biological activity.
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