3-Difluormethyl-5-carbomethoxy-2,4-pyrazole: Molecular mechanism of the formation and molecular docking study

Application of the Molecular Electron Density Theory (MEDT) for the exploration of the [3+2] cycloaddition processes between methyl propynoate 1 and difluoromethyldiazomethane T-1, have been implemented using the DFT/B3LYP/6-311(d,p) level of theory. According to an examination of conceptual DFT indices, difluoromethyldiazomethane (T-1) participates in this reaction as a nucleophile, while methyl propynoate (1) should be considered as an electrophile. This cyclization is regiospecific, as evidenced by the activation and reaction energies, this agrees with the experiment's findings. It was discovered throughout ELF analysis that analyzed [3+2] cycloaddition is realised by a two-step mechanism. In addition, study of interactions of the products studied in this paper with the protein protease Covid-19 (PDB ID: 7R98) were carried out, by means of molecular docking study). The results indicate that the occurrence of the transfer of the proton to the nitrogen atom, increases the affinity of these products to the protein (CA32-F1 and CA32-F2). © 2023.

Efficient One-Pot Synthesis of Indolhydroxy Derivatives Catalyzed by SnCl2, DFT Calculations and Docking Study

In this work we used an efficient and simple synthesis for the preparation of new indolhydroxy derivatives that has been performed by the reduction reaction of 2-nitrocinnamic acid or 2-nitrophenyl pyruvic acid with anhydrous stannous chloride (SnCl2) as a metal catalyst in different alcoholic solvents. During this transformation there was the involvement of intramolecular elimination cyclization. In the case of the reduction of 2-nitrocinnamic acid we obtained hydroxyindole plus hydroxyquinoline, on the other hand, the reduction of 2-nitrophenyl pyruvic acid gives hydroxyindole only, the products were obtained in suitable yields. The structures of all the synthesized compounds were fully characterized by different spectroscopic techniques such as 1H NMR, 13C NMR. In addition, the obtained products have been tested in silico against anti-human immunodeficiency virus type 1 (HIV-1) and SARS-CoV-2 virus. The outcomes of this work are very promising to develop more efficient antiviral compounds, indicating that these products may be a probable drugs for the SARS-CoV-2. © 2022, The Tunisian Chemical Society and Springer Nature Switzerland AG.

Divulging the Regioselectivity of Epoxides in the Ring-Opening Reaction, and Potential Himachalene Derivatives Predicted to Target the Antibacterial Activities and SARS-CoV-2 Spike Protein with Docking Study

The ring-opening reaction of epoxides 1b and 1c utilizing LiAlH4, have been studied within the Molecular Electron Density Theory (MEDT) at the B3LYP/6-31(d) computational level. The regioisomeric reaction paths including the two oxiranes cycles of epoxides 1b and 1c have been explored. DFT calculations show that the attack of the hydride ion H− is favorable on the carbon C3 for the epoxide 1b, while this action is realized on carbon C2 for the epoxide 1c in the highest conformity with the experimental outcomes. Furthermore, we have operated a docking calculation to examine the antibacterial activities of the products 1a-1f, further more we have performed a docking calculation to scrutinize the products 1-9 against SARS-CoV-2. Indeed, the docking results showed that α-himachalene (2) possess a higher affinity to the main protease.

Chemical reactivities and molecular docking studies of parthenolide with the main protease of HEP-G2 and SARS-CoV-2.

We have used bioinformatics to identify drugs for the treatment of COVID-19, using drugs already being tested for the treatment as benchmarks like Remdesivir and Chloroquine. Our findings provide further support for drugs that are already being explored as therapeutic agents for the treatment of COVID-19 and identify promising new targets that merit further investigation. In addition, the epoxidation of Parthenolide 1 using peracids, has been scrutinized within the MEDT at the B3LYP/6-311(d,p) computational level. DFT results showed a high chemoselectivity on the double bond C3[bond, double bond]C4, in full agreement with the experimental outcomes. ELF analysis demonstrated that epoxidation reaction took place through a one-step mechanism, in which the formation of the two new C-O single bonds is somewhat asynchronous.

MEDT study of the 1,3-DC reaction of diazomethane with Psilostachyin and investigation about the interactions of some pyrazoline derivatives with protease (Mpro) of nCoV-2.

The molecular electronic density theory (MEDT) was invested to elucidate the chemo-, regio- and stereo-selectivity of the 1,3-dipolar cycloaddition between Diazomethane (DZM) and Psilostachyin (PSH). The DFT method at B3LYP/6-31 + G (d,p) level of theory was used. Reactivity indices, transition structures theory, IGM and ELF analysis were employed to reveal the mechanism of the reaction. The addition of DZM to PSH takes place through a one-step mechanism and an asynchronous transition states. Eight possible addition channels of reaction were investigated (addition of C (sp2) to Diazomethane at C4, C5, C6 or C7). The addition of C (sp2) at C5 leading to P1 product is the preferred channel. The addition of ether does not affect the chemo-, regio- and stereo-selectivity of the reaction. Analysis of transfer of charges along the IRC path associated with the P1 product shows a polar character for the studied reaction. We have also used the noncovalent interaction (NCI) which is very helpful to reveal the most favored addition channel of the reaction, by analyzing the weak interactions in different TSs. Finally, we investigate about the potential of inhibition of some pyrazoline compounds against COVID-19-Mpro by performing a molecular docking calculations.