3442-62-4Relevant academic research and scientific papers
Pseudomonas fluorescens showing antifungal activity against macrophomina phaseolina, a severe pathogenic fungus of soybean, produces phenazine as the main active metabolite
Carmona, Marcelo,Castaldi, Stefany,Cimmino, Alessio,Evidente, Antonio,Isticato, Rachele,Masi, Marco,Sautua, Francisco,Tuzi, Angela
, (2021/11/23)
Pseudomonas fluorescens 9 and Bacillus subtilis 54, proposed as biofungicides to control Macrophomina phaseolina, a dangerous pathogen of soybean and other crops, were grown in vitro to evaluate their ability to produce metabolites with antifungal activity. The aim of the manuscript was to identify the natural compounds responsible for their antifungal activity. Only the culture filtrates of P. fluorescens 9 showed strong antifungal activity against M. phaseolina. Its organic extract contained phenazine and mesaconic acid (1 and 2), whose antifungal activity was tested against M. phaseolina, as well as Cercospora nicotianae and Colletotrichum truncatum, other pathogens of soybean; however, only compound 1 exhibited activity. The antifungal activity of compound 1 was compared to phenazine-1-carboxylic acid (PCA, 3), 2-hydroxyphenazine (2-OH P, 4), and various semisynthetic phenazine nitro derivatives in order to perform a structure–activity relationship (SAR) study. PCA and phenazine exhibited the same percentage of growth inhibition in M. phaseolina and C. truncatum, whereas PCA (3) showed lower activity against C. nicotianae than phenazine. 2-Hydrox-yphenazine (4) showed no antifungal activity against M. phaseolina. The results of the SAR study showed that electron attractor (COOH and NO2) or repulsor (OH) groups significantly affect the antifungal growth, as well as their α-or β-location on the phenazine ring. Both PCA and phenazine could be proposed as biopesticides to control the soybean pathogens M. phaseolina, C. nicotianae, and C. truncatum, and these results should prompt an investigation of their large-scale production and their suitable formulation for greenhouse and field applications.
Investigation on the photoreactions of nitrate and nitrite ions with selected azaarenes in water
Beitz, Toralf,Bechmann, Wolfgang,Mitzner, Rolf
, p. 351 - 361 (2007/10/03)
The photoreactions of selected azaarenes with nitrate and nitrite ions were investigated under irradiation at λ = 313 nm. The excitation of both anions leads to several photochemical reactions forming mainly hydroxyl radicals and nitrogen oxides. The purification capability of natural waters i.e. the oxidation of inorganic and organic substances results from the formation of hydroxyl radicals. Nitrated isomers of azaarenes were found among the main products of the investigated photoreactions. The nitrogen oxides were responsible for the production of nitrated derivatives which possess a high toxic potential. Their formation was explained by the parallel occurance of two mechanism, a molecular and a radical one. The molecular mechanism became more important with increasing ionisation potentials of the azaarenes. The spectrum of oxidized products corresponded to the one got in the photoreactions of azaarenes with hydrogen peroxide. The formation of several oxidation and nitration products of the pyridine ring with its low electron density was explained by the reaction of excited states of azaarenes. The photoreactions with nitrite ions only led to the formation of oxidized and nitrated products. Nitroso products were not formed. The reactivity of nitrogen monoxide is too low for its reaction with the azaarenes.
Photochemical Reaction of 2,4-Dinitrodiphenylacetamide and Related Compounds: Spectroscopic and Chemical Identification of Intermediates
Fasani, Elisa,Mella, Mariella,Albini, Angelo
, p. 2689 - 2692 (2007/10/02)
2,4'-Dinitrodiphenylacetamide 1b reacts via the triplet state to give 3-nitrophenazine 5-oxide 2b.The initial step is addition of the nitro group to the C=O bond.This intermediate 7 rearranges in the ms time scale to yield an O-acylnitro derivative 8.This, in turn, undergoes heterocyclic cleavage (rate dependent upon solvent polarity) and the aminium cation thus formed cyclizes to 2b.Intermediate 7 is sensitive to acid-catalysed hydrolysis, and the cleavage of 8 and subsequent cyclization are influenced by various additives.Thus, with triphenylphosphine a phosphoranylidenamino derivative is obtained, and 2,6-di-tert-butylphenol gives 4-nitro-2-nitrosodiphenylamine.Two other amides are compared.
