Condensation of imidazol-2-carboxaldehyde and 2-tosylaminomethylaniline (HLTs) in ethanol under reflux yields the Schiff base H2L. The interaction of this Schiff base with palladium(II), cadmium(II) or zinc(II) acetates in 1:1 molar ratio was investigated. This study demonstrates that the expected Schiff base metal complexes cannot be isolated. Instead, chemical synthesis starting from metal acetates leads to the products Pd(LTs)2.2H2O, Cd(LTs)2 and Zn(LTs)2, as a result of the Schiff base hydrolysis.

In our previous work (see ECSOC-16, 2012) we found the interesting dependencies of the alkyl protons chemical shift values in 1-monosubstituted  linear alkanes NMR 1H spectra upon the nature of substituent group, including the alkyl groups as substituents. In continuation of this topic we started more detailed study of the methyl group as a substituent introduced into the molecule of a linear alkane, "moving" it from the beginning to the middle of the alkane molecule. In this paper we describe the effect of the methyl group position in monomethylsubstituted alkane molecule on chemical shift values ​​of all the nuclei of hydrogen atoms in the molecule of this methylalkane (including the newly introduced methyl group). The position of the methyl group in the alkyl chain denoted by the symbol «N», indicating the carbon atom to which is attached "methyl substituent" number from the beginning of the chain. For this purpose we have studied and analyzed the literature values ​​of proton chemical shifts in the 1H NMR spectra of four "methylalkane families": 2 -, 3 -, 4 - and 5-monomethylalkanes (where N = 2, 3, 4 or 5). Each family consists of molecules, ranging from "short-chain" methylbutanes to the most "long-chain" methyldodecanes, for which we can found the "credible" spectral literature data. We compared the protons chemical shift values ​​ of the same type protons, for example, of triprotonic signal of terminal methyl groups in the unsubstituted and studied monomethyl alkanes. We fixed the differences between the compared chemical shifts only  for the cases when the difference is equal or exceeds a value equal to 0.02 ppm. These values ​​of the differences we have identified as "significant" (ie, to be discussed) and randomly selected them for the reason that it is the value of 0.02 ppm we estimate a possible error of experimental determination of protons chemical shift values ​​in the studied molecules. When researching all four families of N-monomethyl alkanes we reveal that a "significant" difference in protons chemical shift values ​​are found only in the so-called "tetracarbon fragments": -СN-1HN-12-CNHN(CH3)-СN+1HN+12-. Each of such fragment comprises a carbon atom N with attached to it "methyl substituent", the previous (N-1) and the following (N +1) carbon atoms. We calculate the mean values ​​for each protons type in these "tetracarbon fragments" in each of the four families of the monosubstituted alkanes. It is shown that the mean chemical shift values ​​for each protons type in these "tetracarbon fragments" slightly differ for families of 3-, 4- and 5-methylalkanes (where N = 3, 4 or 5), in which the "tetracarbon fragment" under consideration is situated in the midchain position, but differ significantly in the case of the family of  2-methylalkanes (where N = 2) in which it is situated at the beginning of the carbon chain.

Since last decade, biocatalysts have become an attractive alternative to conventional chemical methods, especially for organic synthesis, due to their great properties. Among these enzymes, lipases are the most widely used, because they are cheap, easily available, cofactor free and have broad substrate specificity. Combined to microwave irradiation in non-aqueous medium, the published results suggest that microwave irradiation can have an influence on enzyme stability and activity, in addition to altering/enhancing reaction rates and/or enantioselectivities, called nonthermal microwave effects. However, the role of the microwave irradiation on enzyme still reminds controversial. This presentation will deal with the benefits of the use of lipases and the microwave irradiation. To have a better understanding of the system, different parameters were studied and analyzed, such as the impact of the microwave power, the temperature, the role of the solvent, etc. The optimization of the reaction parameters will lead to the obtainment of useful chiral homochiral diols in clean, efficient and safe way. 

In the course of our ongoing studies of natural products from our regional flora with acetylcholinesterase (AChE) inhibitory activity, a bioassay-guided fractionation of the ethanolic extract of Grindelia ventanesis Bartola & Tortosa (Asteraceae) resulted in the isolation of a labdane diterpene of the normal series identified as 17-hydroxycativic acid. Taking into account that this compound showed a significant inhibition of AChE (IC50 = 21.1 μM) and that it was easily isolated from the plant extract in a very good yield (150 mg/ 100 g of aerial parts), we decided to obtain semisynthetic analogs of this natural diterpene through simple structural modifications of the three hot spots of this molecule: the carboxylic group (C15), the double bond (C7-C8) and the primary allylic alcohol (C17). Until now the following transformations have been achieved: reduction of the carboxylic acid to alcohol using LiAlH₄, synthesis of the methyl ester with K₂CO₃ and CH₃I, sulfation with trimethylamine-sulfur trioxide complex and acetylation with Ac₂O/pyridine of the hydroxyl group. These four derivatives are new diterpenes and have been fully characterized by mono- and bidimensional NMR spectroscopy. The results obtained in the in vitro evaluation of their AChE and butyrylcholinesterase inhibitory activity and structure-activity relationship will be discussed.

Aryl- and heteroaryl carbamates (e.g. Carbaryl and Pirimicarb) are known as plant protection agents. Because many pests develop resistances, new carbamate structures are of interest in plant protection research. Our synthetic approach started with the preparation of heterocyclic enoles such as pyrones 3, quinolones 6, and coumarins, quinolines, and pyridones of the general structure 12. They were obtained from 1,3-dinucleophiles such as anilines 1 and 10, phenols 10, and azomethines 10 by cyclocondensation with malonates. The pyrones 3 reacts with dialkylcarbamoylchlorides 4 in the presence of a base to carbamates 5. Degradation of 3 gave 4-hydroxyquinolones 6 which reacted with 4 to carbamates 9. Methylisocyanate 7 led to carbamates 8. Anilines 10 (X = NH, R3-R3 = -CH=CH-CH=CH-) cyclize with 2-substituted malonates 11 to quinolones 12. Similarly, phenols 10 (X = O, R3-R3 = -CH=CH-CH=CH-) react to coumarins 12. Azomethins 10 (X = N-alkyl, N-aryl, R4 either alkyl, aryl or 6- or 7-membered rings) give with reactive malonates pyridones, tetrahydroquinolines or cycloheptapyridones 12. Monocyclic pyridones 12 were also accessible from dehydracetic acid, followed by oxygen exchange with amines. The reaction of dialkylcarbamoylchlorides 4 with enols 12 in the presence of bases formed carbamates 13. With methylisocyanate 7, carbamates 14 were obtained. The evaluation of the biological activity shows, that 2 representatives from structures 6 and 12 exhibit strong plant protection properties.

2-Bromoestrone and 4-bromoestrone and the corresponding estradiol derivatives were converted to 2-fluoroaryl- and 4-fluoroarylestrones and estradiols by Suzuki-Miyaura cross-coupling. The coupling products were subjected to an intramolecular aromatic ipso SN reaction to furnish benzofuranoestrones and estradiols. Suzuki-Miyaura cross-coupling reactions were also carried out with other arylboronic acids, using 2-bromoestrane, 4-bromoestrane and 2,4-diiodoestrane as substrates.

Schiff bases are an important class of compounds with a variety of applications in medicinal, materials and supramolecular chemistry due to their biological (anticancer, antimalaria, antivirus, antimicrobial, etc.) and optical properties (chemosensors, photochromic, nonlinear optical). UV irradiation of these compounds leads to the trans-cis isomerization of the C=N bond with formation of an unstable species that returns thermally with variable speed to the initial form. Recently, we have showed that the kinetic rate of the thermal cis-trans re-isomerization of pyrrolidene Schiff bases, at room temperature, can be controlled through proper substitution at the aniline ring of the molecule.1a As part of an on-going research to develop efficient heterocyclic systems for photochromic applications1a-e we decided to explore the potential of a new series of heterocyclic imines 1 and the corresponding vinyl derivatives 2 functionalized with benzothiazole or benzothiazolium acceptors groups linked to the pyrrole ring through position 2 or 6 of the benzothiazole ring.

We have carried out computational studies on the metal-mediated oxidation of methanol to formaldehyde using Pd(LSB)•3H2O, where LSB is the dianionic form of the Schiff base ligand N-{2-[(8-hydroxyquinolin-2-yl)methyleneamino]benzyl}-4-methylbenzenesulfonamide. With the aim of reducing the overall Gibbs energy of the global process, we have studied the replacement of hydroxymethoxymethyl by hydroxymethyl and aminomethyl groups at 2-position of the quinoline ring.

Thiosemicarbazones belong to a large group of thiourea derivatives, which obtained by condensation of thiosemicarbazide with suitable aldehydes or ketones. They have biological activities, such as antitumour, antiviral, anticancer, antifungal, antibacterial and antimalarial. In this work, 4-pyridinecarboxaldehyde thiosemicarbazone was synthesized by the reaction of thiosemicarbazide (TSC) and 4-pyridinecarbaldehyde in 1:1 molar ratio in ethanol under reflux at 70–80 °C for 2 h. The progress of the reaction was monitored by TLC. After the completion of the reaction, a yellow compound was formed, which was characterized by Fourier transform infrared (FT-IR), ¹H-, ¹³C- NMR spectroscopy and elemental analysis. Spectroscopic data: IR (KBr, cm^-1): 3425(s), 3267(s), 3159(s), 1598(s), 1108(s), 829(m), 619(m), 522(m). ¹HNMR (DMSO-d₆, ppm) δH: 7.74(s, 2H), 7.97 (s, 1H ), 8.19 (s, 1H ), 8. 36 (s, 1H), 8.56 (s, 2H), 11.67(s, 1H) ¹³CNMR (DMSO-d₆, ppm) δC: 122.72, 141.13, 143.07, 151.57, 181.

Multicomponent reactions (MCRs) allow the assembly of complex molecules in one-pot and show a facile execution, high atom-economy and high selectivity, as afford good yields and are fundamentally different from two-component and stepwise reactions in several aspects. Imidazoles are very useful building blocks for the development of molecules that are important in medicinal chemistry. Substituted imidazole derivatives have found applications as diverse biologic activities such as angiotensin inhibitors, anti-inflammatory, glucagon antagonist, antiviral, antimicrobial, fungicidal and high cytotoxicity, which has indicated them as new candidates in cancer therapy. Because of their importance, the methods for their synthesis have become a focus of synthetic organic chemists. In continuation of our interest in the application of new catalysts in organic synthesis via MCRs, herein, an efficient and  highly  selective synthesis of highly substituted imidazoles has been  developed by the condensation of benzil or benzoin with various substituted aldehydes and ammonium acetate using  urea/hydrogen peroxide (UHP) as a supported green catalyst in refluxing ethanol for 2-5 h under mild reaction conditions and excellent yields.