Letters in Organic Chemistry - Volume 20, Issue 5, 2023

Vinylation of activated methines is a synthetically useful and challenging transformation. Traditional methods for this transformation always encounter multiple steps, limited generality and/or handling gaseous substrates. Herein, we report by using diphenyl(vinyl)sulfonium triflate as a vinylation component, a one-step direct vinylation of activated methines can be realized under mild conditions. This reaction, compatible with several kinds of activated methines, can lead to the construction of vinylated quaternary carbon centers concisely.

The activity and selectivity of W110G Thermoanaerobacter ethanolicus secondary alcohol dehydrogenase were altered by cosubstrate and cosolvent at varying temperatures. A sharp drop in the enantiomeric excess (ee) was observed at 60°C in the first 3 h, suggesting increased selectivity mistakes in the reduction of 4-phenyl-2-butanone to the expected (S)-4-phenyl-2-butanol using 5% v/v of 2-propanol as a cosubstrate. The ee increased exponentially with cosubstrate concentration, reaching ≥94% with 30-70% v/v 2-propanol. However, a decrease in enzyme activity was noticed at ≥30% v/v 2-propanol by a sharp drop in conversion. The lowest ee (<3%) was registered using 5% v/v 2- propanol at 30-40°C, which prolonged enzyme life that allowed reversible redox reaction with selectivity mistakes to give the R-alcohol compared to ≥18% ee at 50-60°C, where faster reaction rates promoted selectivity mistake, but enzyme life was shortened by protein denaturation at the elevated temperatures. Water-miscible and immiscible organic cosolvents (25% v/v) increased enzyme selectivity. For methanol, ethanol, ethylene glycol and tert-butanol, the activity/conversion decreased with an increase in pKa and log P while the stereoselectivity/ee increased.

A simple and green methodology has been developed for the synthesis of 3-aryl-5,7- dimethyl-1,2,4-triazolo[4,3-a]pyrimidines in water. Oxidative cyclization of 4,6-dimethyl-2- pyrimidinylhydrazones of different aldehydes was achieved in good to excellent yield using iodobenzene diacetate at room temperature. High efficiency, easy work-up, short reaction time, non-toxicity of solvent and ambient temperature are the advantages of this methodology.

A facile and convenient synthesis of two new and one known impurities of Propisochlor, 2-chloro-N-(2-chloroethanoyl)-N-(2-ethyl-6-methylphenyl)-ethanamide, 2,2-dichloro-N-(2- ethyl-6-methyl-phenyl)-N-(isopropxymethyl)-ethanamide and 2-chloro-N-(2-ethyl-6-methylphenyl)- N-methylethanamide have been developed from the readily available 2-ethyl-6-methylaniline precursor. All the synthesized impurities are characterized using ¹H, ¹³C NMR and mass spectra for their structural elucidation.

A green, solvent-free, and efficient strategy for the assembly of methanobenzo[ d]naphtho[1,2-g][1,3]oxazocine heterocycles using 1-butyl-3-methylimidazolium hydroxide ([bmim]OH) ionic liquid under ball-milling solvent-free condition has been developed. For this purpose, the synthesis of methanobenzo[d]naphtho[1,2-g][1,3]oxazocine derivatives was carried out in a single step and one-pot reaction using 2-naphthol and quinolinium salts with the catalyst, 1-butyl-3- methylimidazolium hydroxide ([bmim]OH), at room temperature. This protocol's specific advantages are environmentally benign media, high yield, easy purification and short experimental time.

Dehydrocostus lactone is biosynthesized in Saussurea lappa (commonly known as costus), Echinops kebericho, and E. amplexicaulis. Since reports described the compound as a bioactive metabolite, many analogues were synthesized to evaluate the structure-activity relationship. In this study, two new analogues of the active principle were synthesized to compare their mycelial growth inhibition potential against two plant pathogens, namely, Fusarium species causing root rot/wilt of faba bean and Phytophthora infestans triggering potato late blight in Ethiopia. Structural changes at the lactone ring of the synthesized compounds led to a decrease in growth inhibition diameter, which describes the role of the α-methylene-γ-lactone moiety in determining the observed bioactivity. The chemical structures of the two new compounds are elucidated using spectroscopic analysis and reported for the first time.

New drug development has been a convoluted, costly, tedious, and difficult job. Overall, enormous sums of money are required for a new drug development pipeline through traditional methods. The pharmaceutical industry faces challenges in diminishing the research cost and time period for new drug discovery. Artificial intelligence has contributed to the industry for quicker, less expensive, and more successful drug designs by giving new paradigms such as computer-aided drug discovery. Recently, the fast development of computational tools for drug discovery is exhibiting remarkable effects on drug design. This article delivers knowledge and success stories of artificial intelligence via Computer Aided Drug Design (CADD) in Medicinal Chemistry and considers the assistance of molecular docking in developing anti-microbial thiadiazole derivatives during the last decade.

This short review focused on the different sensing mechanisms of the chemo and biosensors, which has been regularly exploited during the research in this field. This review focuses on the basic understanding of the electronic changes of the sensors and their interaction with different analytes.

A series of 2-phenyl substituted imidazo-pyridines, pyrazines and pyrimidines were synthesized through an efficient one-pot, environmentally benign, and regioselective strategy which involves the reaction between 2-bromocarbonyl compounds and 2-aminopyridines, 2-aminopyrazines, 2- aminopyrimidines, respectively using A Aloe vera loe vera/water (3:2) as a green promoting media. To the best of our knowledge, this is the first Aloe vera promoted protocol for the synthesis of this important scaffold having potential applications in medicinal and materials chemistry. The use of Aloe vera as a bio-renewable and biodegradable reaction medium-cum-promoter, operational simplicity, use of readily available substrates, mild reaction conditions, broad substrate scope, short reaction time, easy workup, and high yields, makes the disclosed protocol a superior alternative to existing methods. Substituted imidazo-pyridines, pyrazines and pyrimidines were obtained with 95%, 76% and 84% yields, respectively.

Background: Piperazine and its derivatives have many important pharmacological properties such as antimicrobial, antituberculosis, anticancer, antiviral, and antimalarial activity, as well as HIV protease inhibitors and antidepressant activity. Therefore, the structural, spectroscopic, electronic, optic, and thermodynamic properties, and biological activity of the 3-methoxy-1- piperazinylbenzene molecule, which is a piperazine derivative, were investigated in this study. Methods: Theoretical calculations for ligands were carried out with the DFT method by using B3LYP /6-311++G(d,p) basis set except for NMR calculations. NMR analyses were calculated with 6-311++G(2d,p) and were recorded experimentally. Results: Experimental and calculated frequencies are compared and they are in agreement with each other. Also, the Uv-Vis absorbance spectrum for the title molecule was recorded and calculated. They were found to be in harmony with each other. According to the results of molecular orbital analysis and other quantum chemical properties, this molecule has low reactivity and stability. The reactive areas of the ligand were investigated by using MEP map, Fukui functions, and electronic charge analyses, and also performing ELF and LOL analysis. As a result of all these analysis methods, electrophilic regions of the molecule were found to be similar. Some thermodynamic properties at different temperatures and non-linear optical properties were investigated. The increase in enthalpy and entropy values depending on the temperature rise indicates that the thermodynamic structure of the molecule has changed. Also, this molecule has an important non-linear optical response. Conclusion: In biological activity and toxicity studies, the title molecule has an activity against microorganisms and a good drug score.

In the present study, quantum mechanics calculations at the B3LYP theory level and 6- 31G* basis set were carried out to obtain the optimized geometry of carbamates. Then, a comprehensive set of molecular descriptors was computed by using the Dragon software. A genetic algorithm (GA) was also applied to select the suitable variables that resulted in the best-fixed models. The relationship between the molecular descriptors and the partition coefficient of 66 types of carbamates is represented. The molecular descriptors were applied for modeling the multiple linear regression (MLR) and artificial neural network (ANN) methods. The quantitative structure-property relationship models showed that the GA-ANN over the GA-MLR approach resulted in the best outcome. So, the predicted partition coefficient was found to be in good agreement with the experimental partition coefficient. The EEig01x and ALOGP descriptors were applied for modeling the multiple linear regression (MLR) and artificial neural network (ANN) methods. The best model was validated by Q²LOO, Q²F1, Q²F2, Q²F3, and CCC techniques and external validation parameters for the established theoretical models.