In continuation with our research in the use of enols in multicomponent reactions with isocyanides (IMCR), we have used for the first time amide-stabilized enols as the acid component in enol-Ugi reactions. Thus, the reaction of 2-(hydroxy(phenylamino)methylene)-5,5-dimethylcyclohexane-1,3-dione with aldehydes, amines and isocyanides provides the expected enamine adducts. On the other hand, the use of analogous Meldrum’s acid-derived enols permits the synthesis of triamides by a five-component process with the participation of a molecule of solvent. These results confirm the great potential of the enol-Ugi reaction for the preparation of a wide variety of structures containing a peptidomimetic scaffolds.

Activation of the C-C and C‒H bonds are one of the important directions in organic synthesis. Currently, liquid-phase catalytic oxidation of aromatic hydrocarbons has become an independent branch of the technology of organic synthesis. We have developed for the first time a new catalytic method for the preparation of aromatic aldehydes and methyl esters of aromatic carboxylic acids based on the reaction of alkylaryls with methyl hypochlorite generated in situ from the MeOH - CCl4 reagents under the action of a Mn(acac)3 or Mo(CO)6 catalyst. The optimal molar ratios of catalyst and reagents as well as the reaction conditions for the selective synthesis of aldehydes and methyl esters from alkylarylswere found. In contrast to the known processes of oxidation of aromatic hydrocarbons, the developed method does not require the use of expensive organometallic compounds and molecular oxygen.

Virus-induced diseases are very common in our society and continuously, we need new treatments for these challenging infections. We discovered by serendipity some years ago that the molecule 18-(Phthalimide-2-yl) ferruginol, an analogue of the natural diterpenoid (+)-ferruginol, a pharmacologically active molecule, was able to inhibit the spread of dengue virus type-2 (DENV-2) and human herpes virus 1 and 2 (HHV-1 and HHV-2). During the development and further studies of the above-mentioned analogue, we required scaling-up the synthesis of the target molecule. The synthesis was already reported by Waldvogel and co-workers in 2007 starting from the commercially available ca. 60% (+)-dehydroabietylamine in four synthetic steps. In this communication, we describe the several issues that we faced and propose an optimized experimental procedure in order to obtain this broad-spectrum antiviral, which we found that is even active against several strains of Zika virus.

Low molecular weight gelators, LMWG, are small molecules that can self-associate in organic solvents or in water to form fibrous supramolecular architectures and three-dimensional networks that present important applications in several fields. Although various strategies are known for the synthesis of this type of compounds, these are commonly hampered by the use of long multi-step processes that include the protection and deprotection of functional groups. Therefore, it is essential to find direct and robust reactions that allow the simple and efficient introduction of complexity and structural diversity. A promising approach to this end is the use of multicomponent reactions. Based in our experience in this field, here we report our studies aimed at the use of multicomponent reactions of isocyanides to prepare low molecular weight gelators.

The Ritter reaction is widely used in the synthesis of antiallergic, antibiotic, antitumor, antibacterial, influenza antiviral, antiproliferative and antimicrobial drugs. In this regard, the search for new effective catalysts for the synthesis of amidesin mild conditions is an urgent task. Of particular interest is the use of an alcohol as a second substrate. We were the first to carry out the CuBr2-catalyzed reaction of acetonitrile with secondary alcohols such as 2-propanol, 2-butanol, cyclohexanol, cyclopentanol, 2-phenylethanol and adamantanol-2, which gives the corresponding amides in 80-100% yield. CuBr2-Catalyzed reaction of cyclohexanol with a number of nitriles (MeCN, EtCN, PhCN, o-MeC6H4CN) was studied. It was found that the reaction of cyclohexanol with nitriles in the presence of CuBr2 proceeds in three directions giving dicyclohexyl ether, amides and esters (in particular, cyclohexyl acetate and cyclohexyl propionate) depending on the reaction conditions, catalyst concentration and the nature of the nitrile. The methodology we have discovered opens up prospects for the use of copper catalysis in the synthesis of practically useful amides.

Chlorine derivatives of aromatic compounds are widely used in organic chemistry as intermediates for the synthesis of pharmaceuticals. Despite the abundance of various chlorination methods, almost no workon the chlorination of organic compounds using tert-butyl hypochlorite in the presence of catalysts. We have developed a new iron-catalyzed method for chlorination of aromatic compounds using tert-butyl hypochlorite. The reactions take place with high conversion and selectivity. A new method for the chlorination of ethylbenzene and toluene with tert-butyl hypochlorite under the action of iron-containing catalysts to give 1-(chloroethyl)benzene and benzyl chloride in more than 50% yield wasdeveloped. A new iron-catalyzed method for the synthesis of 1,4-dichloro-2,3,5,6-tetramethylbenzene in 100% yield by chlorination of durene with tert-butyl hypochlorite was proposed. A method was developed for the synthesis of phenol and its derivatives (anisole and 4-nitrophenol) with the use of tert-butyl hypochlorite under the action of iron-containing catalysts with a quantitative yield of the reaction products. The developed methodology paves the way for the industrial use of the environmentally friendly reagent in the production of chlorine derivatives of aromatic compounds.

Microencapsulation method is the exhaustively used technique for phase change material (PCM) shape-stabilization. This has been most pervasively used technique in broad spectrum of applications such as building, medical, electronics, food, etc. Polymeric encapsulation is characterized with high toughness and good heat transfer property due to large surface area of capsules. In this paper, phenol-formaldehyde shelled PCM microcapsules (MPCM) were fabricated and their processing parameters were analysed with Taguchi method. Core to shell ratio, surfactant concentration and speed of mixing are the parameters which were optimized in five levels. The optimized values for surfactant concentration, core to shell ratio and agitation speed were 3%, 1:1 and 800 rpm. The obtained microcapsules were spherical in shape. The melting enthalpy of MPCM synthesized with optimized processing parameters was 148.93 J/g in the range of 35-62 ⁰C. The obtained temperature range of phase transition temperature can be used for storing different food articles such as chocolate and hot served foods.

Median lethal concentration values of rodents are commonly used to express the relative risk related to the acute toxicity of new and available chemicals. These toxicity tests are costly and time demanding. Consequently, computational approaches can be used as alternative frameworks. The search for interspecies correlations also represents important substitute methods to the classical mammalian laboratory tests. In this paper we considered rat and mouse acute toxicity data (LD₅₀ values) of organophosphorous compounds (OPs) with diverse structures. Interspecies QSTTR (quantitative structure-toxicity–toxicity relationships) models were developed to predict the oral acute toxicity to a particular species using the available experimental data towards a different species. The multiple linear regression approach was applied to extrapolate the known toxicity of chemicals of interests to species missing toxicity data. OPs structures were optimized by means of molecular mechanics calculations using the MMFF94s force field. Structural parameters were calculated based on the optimized structures. The acute toxicity data of OPs on one species was related to the acute toxicity on another species using the multiple linear regression (MLR) approach. Additional descriptors improved the fitting quality of the MLR models. Model validation was performed using several statistical parameters to test the model predictive power. The results suggest the suitability of the developed QSTTR models to reliably predict the acute toxicity of organophosphorous chemicals.

Purpurogallin (1,7,8,9-Tetrahydroxy-2H-benzo[7]annulen-2-one) is a benzotropolone having a dienic system and is known to inhibits TLR1/TLR2 activation pathway. We have recently described the easy green synthesis of purpurogallin from pyrogallol catalyzed by a copper complex or by vegetable oxidases.

The purpurogalline was acetylated and the tetraacetate derivative thus obtained was engaged in a Diels Alder reaction with various dienophiles (benzoquinone, maleic anhydride, ethylmaleimide, azodicarboxylate, etc.). The results obtained will be presented and discussed. Theoretical calculations using DFT have been performed.

Various copper complexes were prepared (CuCl(phen), Cucl(bipy), CuCl(neocu), CuCl(BPA), [CuCl(OH)(tmeda)]₂ ) and tested in aerobic room temperature oxidation of p-cresol. The complexe [CuCl(OH)(tmeda)]₂ was found has the more efficient and was used in o,o and p,p coupling of various phenols and in the formation of quinones under aerobic conditions. The dimerisation of substitued naphthols was also studied.

These C-H activation with formation of one C-C bond and one harmless molecule of water with air as oxidant at room temperature represent a biomimetic model of enzyme Laccase.