Letters in Organic Chemistry - Volume 18, Issue 2, 2021

A simple and efficient protocol has been established to the synthesis of 3,4-disubstituted isoxazol-5(4H)-ones via Knoevenagel condensation reaction. In this synthesis, succinic acid was used as an inexpensive catalyst and water as a green reaction medium. This method is useful for the preparat ion of various derivatives of 3,4-disubstituted isoxazol-5(4H)-ones in excellent yields.

Silica-POCl2 was used as the promoter for the three-component reaction of ethyl/methyl 3-phenyl glycidate, aniline derivatives, and dimethyl carbonate, leads to the synthesis of methyl/ethyl 2-oxo-4-phenyl-3-aryloxazolidine-5-carboxylate derivatives. The desired product was obtained in high yields.

Benzoimidazolphenylethanamine (BPE) was synthesized through the condensation reaction of 1,2-phenyldiamine and L-phenylalanine. The new complexes were prepared from the reaction of 6- amino-N,N-dimethyluracil (ADU), benzoimidazolphenylethanamine and Cadmium (II), Tin (II), Copper (II) and Nickel (II) metal respectively. All new hybrid complexes were fully characterized by spectroscopic data of FTIR, UV-Visible electronic absorption, thermal analysis, X-ray powder diffraction studies and mass spectroscopy. Spectra analyses of the hybrid metal complexes showed the tetrahedral coordination of the ligands to the metal ions via the nitrogen atoms. The in vitro antibacterial activities of the hybrid complexes were assayed against four bacterial isolates namely, Micrococcus luteus, Staphylococcus aureus as Gram-positive bacteria, Pseudomonas aeruginosa and Escherichia coli as Gram-negative bacteria using the agar well diffusion method. Most of the tested isolates were sensitive to most metal hybrid complexes. The drug-likeness and bioactivity properties were calculated using Molinspiration Cheminformatics software.

A number of new N-alkylated derivatives of N-acylhydrazones have been prepared via one pot three-component reaction between hydrazide, aldehyde, and α,β-unsaturated ester using 1,4-diazabicyclo[ 2,2,2]octane (DABCO), as an inexpensive base and tetrabutylammonium bromide (TBAB), an ionic organic salt media, under solvent-free conditions. In case of 2-hydroxy benzaldehyde, the reaction proceeds with the exclusive formation of the N-alkyl derivative without any concurrent O-alkylation side reaction.

For the first time in the present study, we studied the adsorption effect of the Solriamfetol (SOF) on the electronic and optical properties of B12N12 fullerene using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations with the M062X/6- 311++G(d,p) level of theory in the solvent water. The calculated adsorption energies of SOF drug with the B12N12 fullerene were computed at T= 298.15 K with the M062X functional. The UV/Vis absorption spectra were computed and investigated for the study of the significant changes in interactions between SOF and B12N12 fullerene. The IR spectra were also calculated and investigated. The calculated results indicate that the adsorption of the SOF drug from its internal NH2 group on the B12N12 fullerene (configuration B) has the most chemical stability rather than configuration A and C. According to the NBO results, the SOF molecule and B12N12 fullerene are identified as both electrons donor and acceptor at the complexes B12N12-SOF. On the other hand, the charge transfer occurs between the bonding, anti-bonding, or nonbonding orbitals in the SOF drug and B12N12 fullerene. It is found that the applied B12N12 fullerene can be suitable as a drug carrier for the delivery of SOF as a drug for the treatment of excessive sleepiness.

Helicteres hirsuta, which belongs to the Malvaceae family, is used in traditional medicine to treat malaria, diabetes and cervical cancer. While these uses have not been validated in clinical studies thus far, extracts from H. hirsuta exhibit confirmed antioxidant and potential anti-cancer activity that warrant critical assessment. The aim of this study was to determine the antioxidant properties of different parts of the plant H. hirsuta. The antioxidant capacities of methanol extracts of different plant parts, and specific solvent fractions thereof were determined on the basis of 2,2-diphenyl−1−picrylhydrazyl (DPPH) radical scavenging and total antioxidant activity assays. The ethyl acetate fraction from the leaf material of H. hirsuta has the most potent antioxidant activity with the lowest half maximal inhibitory concentration (IC50) value of 9.50 μg/mL, that is 4 times lower than the IC50 of curcumin. The amounts of methyl gallate and rutin dominated the extracts at 8.62 ± 0.01 and 6.76 ± 0.02 mg/g, respectively, out of a total of 21.00 ± 0.01 mg/g active phenolic fraction. The amount of methyl gallate strongly correlated with total phenolic content and total antioxidant capacity, thus this compound may be useful as a marker of antioxidant activity in common medicinal plants

Gallic acid is abundantly found in amla (Phyllanthus emblica), a deciduous of the family phyllanthaceae. Gallic acid, the major constituent of the plant, was methylated to 3,4,5 trimethoxy gallic acid, which then underwent steglich esterification first with paracetamol and then with 4-hydroxy acetophenone to yield 4-acetamidophenyl 3,4,5-trimethoxybenzoate and 4-acetyl phenyl 3,4,5-trimethoxybenzoate “respectively”. 1H NMR, 13C NMR, UV, FT-IR and mass spectroscopy were used to characterize the synthesized compounds. Density functional theory (B3YLP) using a 6-31G (d,p) basis set has been used for quantum chemical calculations. AIM (Atom in a molecule) approach depicted weak molecular interactions within the molecules, whereas the reactive site and reactivity within the molecule were examined by global and local reactivity descriptors. The HOMO and LUMO energies and frontier orbital energy gaps were calculated by time dependent DFT approach using the IEFPCM model. A small value for the HOMO-LUMO energy gap indicated that easier charge transfer occurs within compound 4. The nucleophilic and electrophilic reactivity was determined by MEP (molecular electrostatic potential) experiment. Polarizability, dipole moment, and first hyperpolarizability values were calculated to depict the NLO (nonlinear optical) property of both the synthesized compounds. The antimicrobial activity was also carried out and broad-spectrum antibacterial activity against several strains of bacteria and certain unicellular fungi were exhibited by synthesized compound 3.

1,2,4-Triazole-3-one (3) obtained from tryptamine was transformed to the corresponding carbox( thio)amides via several steps (6a-d). Their reaction with sodium hydroxide performed the 1,2,4- triazole derivatives (7a-d). Compounds 7a-d treatment by 2-bromo-1-(4-chlorophenyl)ethanoneain an ambiance with sodium ethoxide afforded the compounds (8a-d). The reduction reaction of 8a-d afforded 1,2,4-triazoles (9a-d). The synthesis of (10a-d), (11a-d) and (12a-d) was afforded treatment of products 9a-d with 4-chlorobenzyl chloride (for 10a-d) or 2,6-dichlorobenzyl chloride (for 11a-d) or 2,4-dichlorobenzyl chloride (for 12a-d). Besides the improved of entirely novel agents having various chemical features than those of the existing ones, another aim is to combined two or more groups into a single hybrid compound. For this reason, a single compound containing more than one group, each with various modes of effect, could be helpful for the cure of bacterial infections. Microwave-assisted and conventional techniques were utilized for the syntheses. The structures of recently obtained molecules were elucidated on the foundation of ¹H NMR, ¹³C NMR, FT IR, EI MS methods and elemental analysis. All novel synthesized molecules were investigated for their antimicrobial activity using MIC (minimum inhibitory concentration) method. The aminoalkylation of triazoles (7a-d) formed products 8a-d which have excellent activity against testing bacteria with values between 0.24 and 125 μg/mL. Especially compounds 8a and 8d exhibited much better activity against E. coli than ampicillin used as standard drug. The microwave process ensured a more efficient road to the creation of desired molecules. The antibacterial examination demonstrated that after the carbonyl group is increased the antibacterial activity of the compounds is greatly increased. That's why molecules formed as a result of the alkylation reactions of triazoles has high activity.

A new series of pyrano[2,3-b]quinolines were synthesized from 3-formylquinolin-2(1H)- ones via Knoevenagel condensation followed by cyclization reaction of ethyl cyanoacetate using DMSO as solvent. This methodology is a simple; clean, fast, efficient, eco-friendly method with less reaction time, an improvement in the yield and purity of the product. The structures of newly synthesized compounds were confirmed by IR, NMR, Mass and elemental analysis.

Inorganic base promoted highly selective N-hydroxymethylation of indole and its derivatives have been developed. It provided a simple method for the preparation of N-hydroxymethyl indoles with polyformaldehyde as reagents under the metal- and Lewis acid-free reaction conditions. The reaction proceeded smoothly using K2CO3 as base in 1,4-dioxane to produce the corresponding N-hydroxymethyl indoles with 62%->99% yields.