Irenolone and emenolone: two new types of phytoalexin from Musa paradisiaca

Synthesis and Antifungal Activity of Musa Phytoalexins and Structural Analogs

“…General synthetic procedures A solution of 1 (0.47g, 0.003 mol) in THF (5 mL) was added to the appropriate Grignard reagent (0.004 mol; prepared from the respective bromide and Mg in THF (10 ml)). After stirring for 20 min at -70°C the reaction mixture was allowed to reach room temperature and then was quenched with an aqueous saturated solution of NH 4 Cl. The aqueous phase was extracted with dichloromethane and the combined organic extracts were washed with brine, dried over Na 2 SO 4 and evaporated to dryness.…”

“…The reaction was quenched with NH 4 Cl, the organic phase was separated, dried and evaporated. The residue (2.5 mmol) was dissolved in diethyl ether and several crystals of p-toluenesulfonic acid were added.…”

“…20% [2]. Under colonization by these microorganisms or treatment of the leaves with kanamycin, banana plants produce two types of phytoalexins, 9-phenylphenalenones (also known as musanolones [3]) and 4-phenylphenalenones [4], The main aim of the present work was to synthesize several structurally-related compounds and to determine the relationship between phytoalexin structure and their antifungal effects against M. fijiensis.…”

Synthesis of [phenyl‐13C6]lachnanthocarpone and other 13C‐labelled phenylphenalenones

“…4 In the latter family they are reported as phytoalexins. The biosynthesis of these compounds is a current research topic, and experimental evidence has been obtained for their formation from two phenylpropanoid units through condensation with malonyl-CoA and subsequent cyclization of the diarylheptanoid intermediate.…”

La protección del banano contra la Sigatoka Negra por métodos no biocidas

“…Después de 2 años, se tuvieron disponibles aproximadamente 5mg de un sólido rojo, cuya cromatografía en capa fina, indicó la presencia de una serie de sustancias similares a las que se producían en la hoja de banano en los primeros estadíos de ataque de la Sigatoka Negra, aunque en concentraciones mucho menores c. Análisis estructural de las nuevas fitoalexinas, mediante técnicas bidimensionales de resonancia magnética nuclear (COSY, DEPT, APT, HMQC, HMBC, NOE, ROESY), espectrometría de masas de alta resolución y finalmente, difracción de rayos X. Esas moléculas correspondían a un sistema del tipo fenilfenalenonas, la primera de las cuales fue llamada irenolona (Luis et al 1993 (Luis et al 1996), así como dí-meros, alcoholes y anhídridos.…”