Vol 88, No 11 (2018)

A new procedure has been developed for the simultaneous preparation of terephthalaldehyde and 4-(dibromomethyl)benzaldehyde by catalytic debromophosphoryl- and phosphonyloxylation of 1,4-bis- (dibromomethyl)benzene with P(IV) acid methyl esters. The reaction of 4-(dibromomethyl)benzaldehyde with ortho esters in the presence of sulfuric acid gave the corresponding acetals, whereas in the presence of ZnCl₂ terephthalaldehyde bis-acetals were formed. 4-(Dibromomethyl)benzaldehyde and its acetal were converted to methyl 4-(dibromomethyl)- and 4-(dimethoxymethyl)benzoates which were phosphorylated by the action of chlorophosphines, as well as by successive treatment with phosphorus(III) chloride and P(III) esters.

N-pyridyl-containing cyclic aminomethylphosphines have been prepared via condensation of the corresponding bis(hydroxymethyl)arylphosphines with p-aminopyridine and m-aminomethylpyridine.

New phosphorylated 1,2,4-triazole-3-thiones have been synthesized, and the possibility of their N,Sfunctionalization has been demonstrated. The direction of alkylation of 1,2,4-triazole-3-thiones with ethyl acrylate has been shown to depend on the substituent on the N⁴ atom.

2,2,2-Tribromo-4,6-di-tert-butylbenzo-1,3,2λ⁵-dioxaphospholedioxaphosphole reacted with a terminal alkyne, pent-1-yne, to give a mixture of two isomeric 1,2-benzoxaphosphinine derivatives, 6,8- and 5,7-di-tert-butyl-2-bromo-4-propylbenzo-1,2λ⁵-oxaphosphinin-2-oxides, at a ratio of 5.9: 1. The regioselectivity of substitution of oxygen in the dioxaphosphole fragment by carbon differs from that observed previously in the reaction with 4,6-di-tert-butyl-2,2,2-trichlorobenzo-1,3,2λ⁵-dioxaphosphole: the minor isomer was formed as a result of substitution of the oxygen atom in the ortho position with respect to one tert-butyl group of the initial phosphole.

Hyperbranched polyesters containing terminal p-toluenesulfonylamido and diethoxyphosphorylamido groups have been synthesized, and their complexes with copper(II) and cobalt(II) ions have been prepared. The thermal stability of the ligands and their metal complexes has been studied by differential scanning calorimetry.

The reaction of acryloyl chloride with the monoamine derivative of p-tert-butylthiacalix[4]arene was used to synthesize p-tert-butylthiacalix[4]arene monoacrylamide in the 1,3-alternate conformation. The effect of the nature of the amine on the result of its Michael reaction with the synthesized p-tert-butylthiacalix[4]arene monoacrylamide was studied. The latter was reacted with piperazine to obtain bisthiacalix[4]arene with the macrocyclic fragments in the 1,3-alternate conformation.

The steric structure of the cone and 1,3-alternate stereoisomers of p-tert-butylthiacalix[4]arenes bearing in the lower rim four substituents containing amide and ammonium groups as well as L-tryptophan residues was studied by ¹Н, ¹³С, ¹Н–¹Н NOESY, and ¹Н–¹³С HSQC NMR spectroscopy. The mutual repulsion of the charged ammonium groups and the presence of intramolecular hydrogen bonds in the synthesized compounds can make the peptide bond with the tryptophan residue sterically accessible for enzymes.

Novel fluorescent dyes of the cyanoarylporphyrazine series containing peripheral triazole groups have been synthesized. Their photophysical properties and the local viscosity effect on the fluorescence have been studied. The experiments with cell cultures have revealed rapid accumulation of the dyes in the cells cytoplasm. Photo- and dark cytotoxicity of the compounds have been evaluated by means of the MTT test.

A series of trans-palladium(II) complexes (trans-[PdCl₂L₂], L = ethyl 5-R-2H-tetrazol-2-ylacetate, 5-R-2H-tetrazol-2-ylacetamides, R = Me, Ph) has been synthesized, and their structure has been proved by ¹H and ¹³C–{¹H} NMR and high-resolution mass spectra and X-ray analysis. Antiproliferative activity of the synthesized complexes has been determined, and the mechanism of their interaction with DNA has been studied by UV and CD spectroscopy.

The influence of the nature of stabilizing amphiphilic additives on the dispersion and precipitation of carbon nanoparticles was evaluated. The stabilized systems were tested for adsorption properties with respect to spectral probes and drugs for which purpose the degree of removal and the amount adsorbed were determined spectrophotometrically for dye Orange OT and anti-inflammatory drug indomethacin.

Synthesis of 6-hydroxy-5-[(2-hydroxy-6-oxocyclohex-1-en-1-yl)(2-nitrophenyl)methyl]-1,3-dimethylpyrimidine- 2,4(1H,3H)-dione in a one pot process based on barbituric acid derivatives, 1,3-cyclohexandione and 2-nitrobenzaldehyde in water media involving diethyl amine as a base. The reaction proceeds efficiently, smoothly with high yield. The synthesized compound is characterized by spectral methods and X-ray single crystal diffraction. The ground state molecular geometry of the compound has been calculated using the density functional method (DFT) with 6–311G(d,p) basis set. The calculated characteristics and electronic absorption spectra based on the TD–DFT method demonstrated good agreement with the experimental data. The electronic absorption, frontier molecular orbital analyses (HOMO–LUMO) and nonlinear optical (NLO) properties were also discussed.

A novel series of indazole 13a–13j derivatives has been synthesized. Their structures are confirmed by ¹H and ¹³C NMR, and mass spectral analysis. The compounds are tested for their anticancer activity against four human cancer cell lines including A549 (Lung), MCF7 (Breast), A375 (Melanoma), and HT-29 (Colon), using combretastatin-A4 as a positive control. Most of the synthesized compounds demonstrate potent activity against the above cell lines. Here IC₅₀ values of target compounds range from 0.010±0.0042 to 12.8±3.77 μM and the control drug from 0.11±0.02 to 0.93±0.034 μM. The compounds 13a, 13b, 13e, 13g, 13h, and 13j are determined to be more potent than the positive control.

A series of novel fused bis-aroylbenzodifuran derivatives linked via bis-1,2,3-triazole moiety containing alkane spacers 15, 19a–19d are synthesized in 68–80% yields by the Huisgen cycloaddition (Click) reaction of alkane azides 4–8 with acetylene intermediate 3 followed by cyclization of the corresponding bishydroxyacetophenone derivatives 9–13 with various p-substituted phenacyl bromides 14a–14d. The isolated compounds are characterized by IR, NMR and mass spectral data. The title compounds are screened in vitro for their antimicrobial and antioxidant activities. The results of the studies indicate antimicrobial activity of compounds 16a and 16b compared to that of the standard Streptomycin. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity test of the synthesized compounds indicates the compounds 15d and 16d as highly active as compared to the standard 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT).

The straight forwarded new green approach to the synthesis of N-phenyl benzamidine derivatives catalyzed by copper oxide nanoparticles (CuO_np) under solvent-free conditions (without microwave radiations and with MW radiation) is presented. All synthesized compounds 3a–3k are characterized by FT-IR, NMR, and single crystal XRD analysis and tested for their antioxidant and elastase inhibition activities. The compounds 3i and 3j demonstrate significant free radical scavenging activity. The accumulated data indicate that some synthesized compounds can be recognized as good anti-aging agents.

The symmetry (Oh) and internuclear distances in (O@Nb₆O₁₈)^8–/aq, (O@Ta₆O₁₈)^8–/aq, O@Nb₆O₁₈(Na/K)₈, and O@Ta₆O₁₈(Na/K)₈ clusters were determined by DFT PBE0 calculations. The models of a multicharged cluster in a polarizable aqueous medium and a cluster stabilized by the Na⁺ and K⁺ cations provide the agreement of calculations for the hexaniobate and hexatantalate octaanions wuth X-ray diffraction data.

Acylation of benzothiazinesulfonamides obtained by the oxidation of N-sulfinylaniline and norbornadiene adducts with acid chlorides and carboxylic anhydrides led to the formation of N-acylated sulfonamide hybrid pharmacophores. Molecular and crystal structure of the acylated products was established by X-ray diffraction method.

Alkaline hydrolysis of N,N-disubstituted О,О-dialkyl (aminomethyl)phosphonates gives rise to the corresponding О-alkyl (aminomethyl)phosphonic acids. The reaction of potassium О-alkyl (aminomethyl)-phosphonates with organyl halides involves quaternization of the nitrogen atom to form dipolar aminophosphoryl compounds, aminophosphabetaines.

The reaction of bis(diethylamino)phosphoryl chloride with N-Boc-protected 1-(α-aminobenzyl)-2- naphthol (Betti base) proceeded via O-phosphorylation of the phenolic OH group to form the target product as trifluoroacetate salt. The latter reacted with O,O-diethyl thiophosphorylisothiocyanate to give thiourea bearing a chiral Betti base fragment.

ACKNOWLEDGMENTS should be as follows:

This work was funded by the Deanship of Scientific Research at “Princess Nourah bint Abdulrahman University,” through the Research Groups Program no. RGP-1438-0001.