Search Results (9)

Agro-industrial residues have transitions from being an environmental problem to being a cost-effective source of biopolymers and value-added chemicals. However, the efficient extraction of the desired products from these residues requires pretreatments. Fungal biorefinery is a fascinating approach for the biotransformation of raw materials into multiple products in a single batch. In this study, the ability of Trichoderma asperellum R to convert fruit scrap and green waste into value-added chemicals was tested in solid-state and in nonsterile conditions. A solid-state fermentation protocol for a tray bioreactor was developed using spawn as the inoculum for nonsterile substrates. T. asperellum R drove the fermentation of both substrates, shaping the metabolites that were enriched in the secondary plant metabolites. Strain R showed cellulase activity only when inoculated on fruit scraps, resulting in increased amounts of polysaccharides in the crude extract. This extract was also enriched in vanillic acid and limonoid, which are intriguing compounds due to the increasing interest in their potential as biological nitrification inhibitors or food additives. Finally, trimethoxybenzaldehyde, an interesting chemical building block, was identified in the extracts of the Trichoderma-guided fermentation. The overall results showed that the application of T. asperellum R has potential as a driver to facilitate the extraction of bioactive substances from nonsterile recalcitrant substrates. Full article

An efficient telescoped method for synthesis of 3-phenyl-10-(2,3,4-trimethoxyphenyl)-9,10-dihydro-4H,8H-pyrano[2,3-f]chromene-4,8-dione was elaborated. The presented protocol includes the one-pot multicomponent reaction of 7-hydroxy-3-phenyl-4H-chromen-4-one, 2,3,4-trimethoxybenzaldehyde and Meldrum’s acid. Advantages of this method are the application of readily available starting reagents, atom economy and easy procedure of preparation and purification of the target product. The structure of the synthesized polycyclic compound was proved by ¹H, ¹³C-NMR, IR spectroscopy and high-resolution mass spectrometry with electrospray ionization (ESI-HRMS). Full article

The treatment of benzylidenemalononitriles with phenylhydrazines in refluxing ethanol did not provide pyrazole derivatives, but instead furnished hydrazones. The structure of hydrazones was secured by X-ray analysis. The chemical proof was also obtained by direct reaction of 3,4,5-trimethoxybenzaldehyde with 2,4-dichlorophenylhydrazine. Newly synthesized hydrazones were tested against eight Candida spp. strains in a dose response assay to determine the minimum inhibitory concentration (MIC₉₉). Five compounds were identified as promising antifungal agents against Candida spp. (C. albicans SC5314, C. glabrata, C. tropicalis, C. parapsilosis and C. glabrata (R azoles)), with MIC₉₉ values ranging from 16 to 32 µg/mL and selective antifungal activity over cytotoxicity. Full article

Monoterpenes, which have a unique diverse structure and are inexpensive, available and often enantiomerically pure, are an attractive renewable raw material for the development of physiologically active agents. One of the most important methods for the utilization of monoterpenes is their interaction with carbonyl compounds, which produces heterocyclic compounds. Often these products exhibit analgesic, antiviral or neuroprotective properties. Earlier, we discovered the anti-influenza A (H1N1) virus activity of several compounds with a hydro-2H-chromene scaffold, which were synthesized by the Prins reaction using p-menthane alcohols and carbonyl compounds; montmorillonite K10 or nanosized halloysite catalyst were used as the reaction catalysts [1]. Chromenols produced from an (–)-isopulegol and aliphatic ketones (acetone and cyclopentanone) demonstrated a high activity combined with a low toxicity against the influenza virus [1]. The introduction of the fluorine atom into the molecule is an important strategy in the development of new biologically active compounds, enabling lipophilicity and electrostatic interactions to change and increasing the metabolic stability of compounds, which affects their physiological activity. Here, we synthesized fluoro- and hydroxy-containing octahydro-2H-chromenes by the Prins reaction starting from an (–)-isopulegol and a wide range of aromatic aldehydes in the presence of the BF₃∙Et₂O/H₂O system, acting as both an acid catalyst and a fluorine source. The activity of the synthesized compounds against the influenza A/Puerto Rico/8/34 (H1N1) virus was studied. The highest activity was demonstrated by fluoro- and hydroxy-containing 2,4,6-trimethoxybenzaldehyde derivatives. These compounds were supposed to be capable of binding to viral hemagglutinin, which is an agreement with data on the effect of compounds on viral fusogenic activity, as well as with molecular docking studies. Full article

Two new compounds, 8-(3,4,5-trimethoxybenzylidene)-6,10-dioxaspiro[4,5]decane-7,9-dione (J1) and 8-(3,4,5-trimethoxybenzyl)-6,10-dioxaspiro[4,5]decane-7,9-dione (J2) have been designed and generated by the reaction of 3,4,5-trimethoxybenzaldehyde with 6,10-dioxaspiro[4,5]decane-7,9-dione in different solvents. The 3,4,5-trimethoxybenzyl group of the two compounds connects with the dioxaspiro group via double bond (J1) and single bond (J2), respectively. The crystal structure determinations show that Compound J1 belongs to the triclinic system, space group P-1 with a = 5.4056(11) Å, b = 11.465(2) Å, c = 13.502(3) Å, α = 92.06(3)° Å, β = 91.35(3)°, γ = 93.50(3)°, C₁₈H₂₀O₇, Mr = 348.34, V = 834.4(3) ų, Z = 2, Dc = 1.386 g/cm³, F(000) = 368. Compound J2 is also of the triclinic system, space group P-1 with a = 8.8778(18) Å, b = 9.5285(19) Å, c = 11.082(4) Å, α = 89.69(3)°, β = 67.38(3)°, γ = 81.68(3)°, C₁₈H₂₂O₇, Mr = 250.36, V = 854.9(3) ų, Z = 2, Dc = 1.361 g/cm³, F(000) = 372. Both compounds form three-dimensional network structures via C–H···O intra- and intermolecular hydrogen bonds. Full article

Thirty-seven commercial aldehydes containing aliphatic chains and aromatic rings as well as heteroaromatic rings were evaluated for their inhibitory activities against Chinese amaranth (Amaranthus tricolor L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv). Polysorbate 80 (Tween^® 80) was used as a surfactant and the research was preliminarily conducted at 400 μM of all aldehydes. Among these aldehydes, (E)-cinnamaldehyde (7) showed the greatest inhibitory effect on seed germination, shoot and root growth of Chinese amaranth by 54.55%, 75.53%, and 85.13% respectively. Similarly, (E)-crotonaldehyde (5), a related α,β-unsaturated aldehyde, inhibited the germination and seedling growth of the tested species at a high percentage. Apart from these two unsaturated aldehydes, no other aliphatic aldehydes had a harmful effect on Chinese amaranth. In terms of benzaldehyde (6), it had no effect on the tested plant; however, many of its derivatives displayed some inhibitory activity. Furthermore, for the ten common heteroaromatic aldehydes, picolinaldehyde (32) had a high inhibitory effect on Chinese amaranth which closely related to the effect of (E)-crotonaldehyde (5) and (E)-cinnamaldehyde (7), whereas, other heteroaromatic aldehydes showed lower effects. In the case of a monocot plant, barnyardgrass, no tested aldehydes reduced seed germination, however, (E)-cinnamaldehyde (7), 2,4,6-trimethoxybenzaldehyde (16) and 4-(dimethylamino)benzaldehyde (24) could inhibit the seedling growth of the plant with low to moderate levels. The herbicidal effects of the most active aldehydes were then further investigated in order to find the minimum concentration of these aldehydes suppressing the germination and growth of the tested plants. At concentrations as low as 50–100 μM some aldehydes could inhibit the seedling growth of the tested species. The structure-activity relationship (SAR) study reported here demonstrates the chemical clues governing the inhibitory activity of aldehydes which could be utilized in the development of highly effective herbicides in the near future. Full article

In this article we describe a new methodology for the total synthesis of 3,4-unsubstituted coumarins from commercially available starting materials. Six examples were prepared, including five naturally occurring coumarins—7-hydroxy-6,8-dimethoxy-coumarin (isofraxidin), 7-hydroxy-6-methoxycoumarin (scopoletin), 6,7,8-trimethoxy-coumarin, 6,7-dimethoxycoumarin (scoparone), and 7,8-dihydroxycoumarin (daphnetin) and one synthetic coumarin, 7-hydroxy-6-ethoxycoumarin. Moreover, five important o-hydroxybenzaldehyde intermediates were also obtained, namely 2,4-dihydroxy-3,5-dimethoxybenzaldehyde, 2,4-dihydroxy-5-methoxybenzaldehyde, 5-ethoxy-2,4-dihydroxy-benzaldehyde, 2-hydroxy-3,4,5-trimethoxybenzaldehyde, and 2-hydroxy-4,5-dimethoxy-benzaldehyde. The method developed herein involves just three or four steps and allows for the rapid synthesis of these important molecules in excellent yields. This is the first synthesis of 6,7,8-trimethoxycoumarin and 7-hydroxy-6-ethoxycoumarin. Full article

New α-aminophosphonates were synthesized by the Kabachnik-Fields reactionof 3,4,5-trimethoxybenzaldehyde (TMB) with p- or m-bromoaniline and a dialkylphosphite under solvent-free conditions. TMB was prepared from gallic acid via a fourstep synthetic sequence involving etherification, esterification, hydrazidation andpotassium ferricyanide oxidation. The structures of all synthesized compounds wereconfirmed by elemental analysis, IR, ¹H-, ¹³C- and ³¹P-NMR spectral data. Compound 7gwas also characterized by X-ray crystallography. A half-leaf method was used todetermine the in vivo curative efficacy of the eight title products against tobacco mosaicvirus (TMV). It was found that compounds 7g and 7h possess good in vivo curativeeffects against TMV. Full article