Vol 88, No 3 (2018)

Vinylidene chloride and 1,2-dichloroethene react with sulfur in the system hydrazine hydrate–KОН with the formation of polyvinylenesulfide oligomer of molecular mass 1750–6120 Da containing also vinylenehydrazine and vinylenechloride links in the Z-configuration, and 1,4-dithiine in the yield up to 46%. In aqueous-hydrazine layer polysulfide anions S_n^2– (n = 1–4), mainly S₂^2– were found. The mechanism of formation of oligomers and 1,4-dithiine is suggested, which includes in the first stage dehydrochlorination of dichloroethenes and generation of chloroacetylene.

Tricyclic diesters were synthesized in yields of 70.4–90.8% by the addition of С₂–С₅ monobasic carboxylic acids to tricyclo[5.2.1.0^2,6]dec-3-еn-8-yl acetate in the presence of a BF₃·OEt₂ catalyst. One of the synthesized diesters, tricyclodec-3,8-diyl diacetate, has a pleasant smell with a citrus scent and can be used in different perfume compositions as a flavoring.

Vanadium compounds and complexes activated by pyridine or morpholine catalyze condensation of ethyl cyanoacetate with ketones and aldehydes leading to alkylidenecyanoacetates in 75–100% yield.

The reaction of N-tosylates of 2-(1-cycloalken-1-yl)anilines and 2,3,9a,9-tetrahydro-1H-carbazole with methanol in the presence of CuBr₂ proceeds with high regioselectivity leading to the corresponding tosylates of 2-(6-methoxy-1-cycloalken-1-yl)anilines and 4-methoxy-1,2,3,4-tetrahydrocarbazole. The latter as well as N-mesyl-1,2,3,4-tetrahydrocarbazole showed moderate cytotoxic activity with respect to HEK293 cell line.

2-(5-Methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-4H-benzo[e]-1,3,2-dioxaphosphorin-4-one reacts with perfluorodiacetyl, 3,6-di(tert-butyl)-1,2-benzoquinone and phenanthrenequinone only with the participation of a three-coordinated phosphorus atom to form spirophosphoranes containing acyclic 5-methyl-2- phenyl-2H-1,2,3-diazaphosphol-4-yl substituent, whereas the interaction with tetrachloro-1,2-benzoquinone proceeds via expanding the six-membered heterocycle to the nine-membered one to form 2-(2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-2,9-dioxo-4,5,6,7-tetrachlorodibenzo[d,h]-1,3,8-trioxaphosphonine.

Alkylation of pentaerythritol symmetrically substituted with propylene glycol with propargyl bromide afforded compounds containing two or three alkyne moieties. Amidophosphite reagents and solid supports were prepared for the introduction of two and three acetylene fragments into oligonucleotides at the 3'- and 5'-positions and inside the chain under conditions of automated solid-phase oligonucleotide synthesis. Based on the trialkynyl derivative, an N-hydroxysuccinimide ester was obtained which can be used to modify biomolecules attacking the amino group. Conjugates obtained can be used for multiple modifications by [3+2] dipolar cycloaddition reaction.

Trichlorogermane triethylaminate [HGeCl₃·NEt₃] has been synthesized and its structure investigated using the methods of NMR and IR spectroscopy and quantum chemistry. Possible structures of complexes of triethylamine with trichlorogermane are considered. The presence of two minima on the potential energy surface is shown; the global minimum corresponds to the structure with proton transfer to the nitrogen atom, [Et₃NH]⁺[GeCl₃]^–, while the local minimum lying by 25.8 kcal/mol above is characterized by the presence of very weak van-der-Waals interaction N···Ge. The comparison of the experimental and calculated chemical shifts of the proton is indicative of the formation of complex with proton transfer to the nitrogen atom in the liquid phase.

Two earlier unknown complexes, [Cu(en)₂(Hptt)]Br (Hptt = 1-phenyl-1H-terazole-5-thiol, en = ethylenediamine) and trans-[Cu(en)2(H2O)Br]Br, have been synthesized and characterized using X-ray diffraction analysis. In [Cu(en)₂(Hptt)]Br complex, the copper cation is bonded with the N⁴ atom of tetrazole ring. Catalytic activity of the obtained complexes in cross-coupling reaction of 1-phenyl-5H-tetrazole-5-thiol with iodobenzene is comparable to that of CuBr₂ in the presence of 2 eq. of ethylenediamine.

The platinum(II) and palladium(II) complexes [Pt₆(SCH₂CH₂NH₂)₈]Cl₄ and [Pd₆(SCH₂CH₂OH)₈ Cl₄· 5H₂O with mercamine and β-mercaptoethanol, respectively, were synthesized. It was found on the basis of the comparison of IR and X-ray electron spectra of the ligands and complexes, and also of the data of X-ray diffraction analysis that the bidentate coordination of ligands through sulfur and nitrogen atoms is realized in the platinum(II) complex. In the palladium(II) complex β-mercaptoethanol is coordinated in a mixed-mode type. In both complexes sulfur atoms of the ligands occupy a bridging position.

Radical copolymerization of N-vinylpyrrolidone with crotonic acid in 2-propanol has afforded water-soluble products, which have been characterized in terms of composition as well as molecular and hydrodynamic parameters. The obtained copolymers have been modified with 4-oxybenzaldehyde. Structures of the products of the polymer analogous reaction, potential carriers of several bioactive substances, have been confirmed using elemental and functional analysis and spectroscopic data.

A number of anatase derivatives doped with iron, yttrium, and vanadium oxides were synthesized in a pressure reactor at 250°C by the solvothermal method in a solution of anhydrous capronic acid. It was shown that at certain iron and yttrium concentrations the photocatalytic activity of obtained samples exceeds the activity of the titanium dioxide nanopowder Aeroxide^® P25 used as a standard.

Acetic acid functionalized poly(4-vinylpyridinium) bromide is a highly efficient and recyclable catalyst for the construction of 2,4,5-trisubstituted imidazole derivatives by a three-component condensation of benzyl with various aldehydes and ammonium acetate under solvent free conditions. The microwave initiated process leads to analytically pure compounds within 2–5 min. The advantages of this “green” methodology are cost-effectiveness, simple procedure, low energy consumption, no involvement of organic solvents, safe operation, clean reaction profile, high yields, and recyclability of the catalyst.

A series of palladium(II) complexes with N,N-dimethylthiourea and phosphines [tri-p-tolylphosphine (Tptp), benzyl(diphenyl)phosphine (Bdp), cyclohexyl(diphenyl)phosphine (Cdp)] were synthesized by the direct reaction of K₂[(PdCl₄)] with the corresponding phosphines and then with N,N-dimethylthiourea at a molar ratio of 1: 2: 2. The general formula of these complexes is [Pd(L1)₂(L₂)₂]Cl₂, where L1 = N,N-dimethylthiourea (Dmtu), L2 = Tptp, Bdp, Cdp. The complexes were characterized by elemental analyses, multinuclear NMR (¹H, ¹³C, ³¹P), and FT-IR. The complex with cyclohexyl(diphenyl)phosphine was also characterized by single crystal X-ray analysis. The spectral and crystallographic data suggest monodentate coordination of dimethylthiourea through the sulfur atom and of the phosphine ligand through the phosphorus atom and distorted square planar environment of palladium(II). The synthesized complexes have been screened for DNAbinding, antibacterial, cytotoxic, and antitumor activities. The complexes show interaction with DNA via intercalative mode. The complexes show good activity against both gram positive and gram negative bacteria as compared to that of a standard drug, Imipenem. Their antitumor activity against MCF7 tumor cell line was found to be comparable with doxorubicin. MTT assay was used to investigate the cytotoxicity of the studied compounds having activity order: 3 > 2 > 1.

An optimized catalytic oxidative cost effective process of dehydrogenative coupling of diisopropyl phosphite with arylamines led to formation of the corresponding phosphoramidates. Structures of products were elucidated from NMR and ESI-MS data.

New mononuclear complexes of Pd(II), Ag(I), Pt(IV), and Hg(II) with nifuroxazide were synthesized by the reaction of the metals salts with the drug. The complexes were characterized by elemental and thermal analysis and FT-IR, ¹H NMR, and UV–Vis spectra. Stoichiometry of the complexes was determined to be 1: 2. Nifuroxazide (Nif.) drug is coordinated to the metal ions as a bidentate ligand via oxygen and nitrogen atoms of the C=O and hydrazone groups. Density functional theory (DFT) calculations were carried out at the B3LYP levels with LANL2DZ basis set for Ag(I) and Hg(II) ions, LANL2MB basis set for Pd(II) and Pt(IV) ions, and 6-31G(d,p) basis set for the other atoms. The complexes had high thermal stability. Tests for anticancer activity, breast cancer cell line (MCF7), demonstrated that Hg(II), Pt(IV), and Pd(II) metal complexes had higher activity than the free ligand.

Novel 5-{(1-[(1-phenyl-1H-1,2,3-triazol-4-yl)methyl]-1H-indol-3-yl)methylene}pyrimidine-2,4,6-(1H,3H,5H)trione derivatives (5a–5k) were synthesized by the click reaction. All compounds 5a–5k were characterized by ¹H and ¹³C NMR, IR and Mass spectra and evaluated for their in vitro anticancer activity against cervical cancer cell lines. Among all, compound 5e (IC₅₀ = 6.76 μM), shown high inhibitory activity. Docking analysis of all the compounds with the Lipid kinase PI3K-α revealed that the compound 5e fitted well in the active site pocket, showing the best docking score (LibDock) of 123.274.

Enthalpies of dissolution of the binary salt LiCl·3CsCl·4H₂O and dry mixtures of lithium and cesium chlorides in the molar ratio 1: 3 were measured by the calorimetry method. The value of the mutual influence of ions in solution was determined, and the enthalpy of the binary salt formation from the individual components was calculated.

Refluxing equimolar amounts of acylhydrazides with triethyl orthoformate in o-xylene yielded 2-aryl-1,3,4-oxadiazoles luminescing with high quantum yields in polar and nonpolar solvents (λm fl ax 299–349 nm, φ 0.20–0.62). The only exception was 2-(1,3,4-oxadiazol-2-yl)phenol emitting intensely only in highly polar aprotic DMSO (λ_max^fl 350 nm, φ 0.19).

Complexes of Fe(II) and Mn(II) with N-(2-hydroxybenzamido)phthalimide of the general formula [M(LH)₂] were synthesized and studied by IR, electronic absorption, and ESR spectroscopy and thermogravimetry. The ligand coordinates to Fe(II) and Mn(II) through the oxygen atom of the amido group which is present in the enolic form.

Conditions for the synthesis of dispersion titanium dioxide with a developed roughness by molecular layering on the silicon surface were determined and structural characteristics of the resulting layer were studied. Electroactive surface area of the titanium dioxide nano-roughened films obtained by the proposed method is higher than those of the reference (smooth) titanium oxide film and the reference silicon electrode by factors 1.1 and 1.2, respectively.