The title compound, C3H6N4O2, exhibits partial disorder with the refined occupancy ratios of the two components being 0.582 (5):0.418 (5). In the major component, the nitroso groups have a relative syn spatial arrangement [O=N⋯N=O pseudo-torsion angle = 1.1 (4)°], whereas the other component has an anti disposition [177.6 (1)°]. The N—N=O moieties are almost coplanar with a dihedral angle of 5.3 (3)°, while in the minor occupied set of atoms, this angle is 8 (1)°. In both components, the imidazolidine ring adopts a twisted conformation on the C—C bond and the crystal structure shows the strain of this ring according to the N—CH2—CH2—N torsion angles [25.9 (5) and −23.8 (7)°]. In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds.

An efficient methodology to obtain novel antifungal analogs of brassinin 1 is described. Starting from L-tryptophan 2, N,N -dialkylthiourea 4, 4-[(1H-indol-3-yl)methylene]-2-sulfanylidene-1,3-thiazolidin-5-one 5 and alkyl (2S)-3-(1H-indol-3-yl)-2-{[(alkylsulfanyl)carbonothioyl]amino} propanoate 6 type compounds were obtained as main products in different ratios depending on the reaction conditions via a tandem dithiocarbamate formation and Michael addition reaction. In order to understand the dependence of the reaction conditions on the mechanism pathway, a DFT/B3LYP study was performed. The results suggested the existence of competitive mechanistic routes which involve the presence of an ionic dithiocarbamate intermediate 9. Antifungal activities of all products were then evaluated against Fusarium oxysporum through mycelial growth inhibition using a microscale amended-medium assay. IC 50 values were thus determined for each compound. These results showed that 6-related compounds can be considered as promissory antifungal agents.

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There is a continuous search for more reliable and effective alternatives to control phytopathogens through different strategies. In this context, indole-containing phytoalexins are stimuli-induced compounds implicated in plant defense against plant pathogens. However, phytoalexins' efficacy have been limited by fungal detoxifying mechanisms, thus, the research on bioisosteres-based analogs can be a friendly alternative regarding the control of Fusarium phytopathogens, but there are currently few studies on it. Thus, as part of our research on antifungal agents, a set of 21 synthetic indole-containing phytoalexin analogs were evaluated as inhibitors against the phyopathogen Fusarium oxysporum. Results indicated that analogs of the N,N-dialkylthiourea, N,S-dialkyldithiocarbamate and substituted-1,3-thiazolidin-5-one groups exhibited the best docking scores and interaction profiles within the active site of Fusarium spp. enzymes. Vina scores exhibited correlation with experimental mycelial growth inhibition using supervised statistics, and this antifungal dataset correlated with molecular interaction fields after CoMFA. Compound 24 (tert-butyl (((3-oxo-1,3-diphenylpropyl)thio)carbonothioyl)-l-tryptophanate), a very active analog against F. oxysporum, exhibited the best interaction with lanosterol 14α-demethylase according to molecular docking, molecular dynamics and molecular mechanic/poisson-boltzmann surface area (MM/PBSA) binding energy performance. After data analyses, information on mycelial growth inhibitors, structural requirements and putative enzyme targets may be used in further antifungal development based on phytoalexin analogs for controlling phytopathogens.Molecules 2020, 25, 45 2 of 19 fungal toxins [2]. In this context, some control strategies based on chemical, physical and cultural methods have arisen to mitigate the negative effects of this phytopathogen to host plants. Chemical treatments include formaldehyde applications to avoid disseminations as well as dazomet, sodium methan, methyl isothiocyanate and systemic fungicides as benomyl, thiabendazon, carbendazim and methylthiophanate [3]. Fusarium-caused diseases treatment by systemic fungicides, although it has good effectivity, is also problematic, since these kind of treatments can become mutagenics for several plants and these agents can also generate high degrees of resistance [3,4].Plants involve a systemic defense mechanism involving some metabolites such as phytoalexins. These metabolites are synthesized in adjacent areas of healthy cells to those damaged cells and they are accumulated both in necrotic and susceptible resistant tissues [5]. In other words, they are strictly produced in a site around the place where infection needs to be controlled. Thus, the resistance occurs when one or more phytoalexins reach a high enough concentration to inhibit the pathogen development [5]. However, some phytopathogens are recently described to exhibit strategies to invade the plant tissues and obtain necessary nutrients for its growing and reproduc...

The molecular structure of the title compound, C21H26N2O2, shows two intra­molecular O—H⋯N hydrogen-bonding inter­actions. In the crystal structure, mol­ecular chains are formed along the c axis through weak C—H⋯O inter­actions. Neighbouring chains are weakly associated along the a axis via C—H⋯π inter­actions.