Podolactones synthesis

The main drawback of the first method described by Barrero et al. [14] for the synthesis of podolactones, lies in the presence of a mixture of three isomers called communic acids (153), which requires a chromatographic separation over silicagel impregnated with 20% silver nitrate to eliminate mirceo-communic acid to allow use of the 2-component mixture of cis- and trans-isomers as starting material. Furthermore, some steps in this former synthetic strategy, such as the closure of the 6-lactone or the formation of the dienolide system need improvement. 

As indicated in the section describing the structures of natural dilactones, wentilactone B was wrongly assigned when the structure of 30-hydroxy-13,14,15,16-tetranorlabda-7,9(ll)-dien-(19,6(J),(12,17)-diolide was isolated. Our synthesis of this compound allows the reassignment of the structure of wentilactone B. Thus, the hydroxyl group of this natural podolactone should be relocated at C-2 with an a- configuration [87]. Two double cyclization steps were employed in this synthesis. The first involves the construction of the bicyclic skeleton via a Mn(III)-mediated... 

The First Synthesis of the Antifungal Oidiolactone C from rrans-Communic Acid Cytotoxic and Antimicrobial Activity in Podolactone-related Compounds. Barrero, A.F. Arseniyadis, S. Quflez del Moral, J. F. Herrador, M. M. Valdivia, M. Jimenez, D. J. Org. Chem. 2002,67,2501-2508. 

Preparation of bioactive podolactones via a new Pd-catalysed bislactonization reaction. Synthesis of oidiolactone C. Barrero, A. F. Quflez del Moral, J. F. Cuerva, J. M. Cabrera, E. Jimenez-Gonzalez, D. Tetrahedron Lett. 2000, 41, 5203-5206. 

More specifically, compounds like podolactone A (Fig. 10.1) inhibit proton efflux from plant cells induced by fusicoccin, without affecting ATP levels.42 The related compound, podolactone E is a strong inhibitor of 6-aminolevulinic acid and chlorophyll synthesis.34 The authors concluded that this was caused by suppression of synthesis of proteins needed in the porphyrin pathway because podolactones also inhibited gibberellic acid-induced a-amylase synthesis in barley embryos. The molecular target site(s) of this class of terpenoid phytotoxins remains to be determined. 

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