Том 55, № 10 (2019)

Cloprostenol methyl ester was converted to the corresponding Δ^11,13-15-keto analog through 9,11-dihydroxy-15-oxo derivative which was subjected to exhaustive acylation and DBU-promoted removal of the 11-acetoxy group. The key stages of the transformation included protection of the 9,11-dihydroxy functionality of cloprostenol methyl ester via conversion to cyclic phenylboronate, in situ oxidation of the unprotected 15-hydroxy group of the latter, and exhaustive acetylation to obtain the corresponding diacetate as precursor to the target compound. An alternative synthetic path starting from 9α,11α-O-bis[tert-butyl(di-phenyl)silyl]-15-oxo derivative of cloprostenol methyl ester has also been proposed.

The azo coupling of arenediazonium chlorides with (Z)-2-(3,3-dimethyl-3,4-dihydroisoquinolin-1(2H)-ylidene)-N-(4-methylphenyl)acetamide afforded (Z)-2-(2-arylhydrazinylidene)-2-(3,3-dimethyl-3,4-dihydroisoquinolin-1-yl)-N-(4-methylphenyl)acetamides whose structure was confirmed by ¹H NMR and X-ray diffraction data. The azo coupling products containing no p-tolyl substituent on the amide nitrogen atom exist in solution as mixtures of azo and hydrazone tautomers. Electronic absorption spectra of the synthesized compounds were studied.

Deboration of 1-PhCH₂-1,2-C₂B₁₀H₁₁ by heating in ethanolic potassium hydroxide afforded Me₄N⁺ [7-PhCH₂-7,8-C₂B₉H₁₁]⁻ which was treated with excess halosuccinimide (NCS, NBS) in acetonitrile or with elemental iodine or bromine in methanol to obtain Me₄N⁺ [7-PhCH₂-9,11-X₂-7,8-C₂B₉H₉]⁻ (X = Cl, Br, I). The reaction of 1-PhCH₂-1,2-C₂B₁₀H₁₁ with an equimolar amount of iodine gave a mixture of Me₄N⁺·[7-PhCH₂-11-I-7,8-C₂B₉H₁₀]^- and Me₄N⁺[7-C₆H₅CH₂-9-I-7,8-C₂B₉H₁₀]⁻ at a ratio 1:1.8 due to steric effect of the benzyl substituent. The ¹¹B chemical shifts of each μ-H tautomer of Me₄N⁺ [7-PhCH₂-9,11-X₂-7,8-C₂B₉H₉]⁻ (X = H, F, Cl, Br, I) were calculated at the DFT level of theory, and their contributions to the average ¹¹B NMR spectrum and the corresponding tautomeric equilibrium constants were determined.

Umbelliferone-6-carbonyl chloride reacted with amines and α-, β-, and ω-amino acid methyl esters to afford the corresponding N-substituted 7-hydroxy-2-oxo-2H-chromene-6-carboxamides. The reaction of umbelliferone-6-carbonyl chloride with glycine gave 2-(7-hydroxy-2-oxo-2H-chromene-6-carboxamido)acetic acid which was converted into acid chloride, and the latter reacted with benzylamines and α-amino acid methyl esters to produce compounds containing a dipeptide fragment.

A procedure for the synthesis of 2-(diethylamino)-N-(2-methylphenyl)acetamide nitrate (monomecaine) exhibiting a pronounced antiarrhythmic activity has been optimized. A procedure for its identification and quality control of the drug substance by HPLC has been developed, and the limit of detection of o-toluidine impurity therein has been estimated at 0.02%. Procedures for HLPC and extraction-titration quantification of monomekain in the drug substance have been proposed and validated. The obtained relative standard deviation (RSD) indicates good specificity, linearity, and precision of the developed procedures.

9-Substituted 2-(5-nitrofuran-2-yl)-9H-imidazo[1,2-a]benzimidazoles were synthesized for the first time by cyclization of quaternary salts obtained from 1-substituted benzimidazol-2-amines and 2-bromo-1-(5-nitrofuran-2-yl)ethan-1-one. 9-R-2-Methyl(aryl)-9H-imidazo[1,2-a]benzimidazoles reacted with 5-nitrofuran-2-carbaldehyde and 4-nitrobenzaldehyde to give the corresponding secondary alcohols as a result of aldehyde addition to the 3-position of the tricyclic system. The Witting olefination of ethyl 2-(bromomethyl)-9-methyl-9H-imidazo[1,2-a]benzimidazole-3-carboxylate afforded 2-ethenylimidazo[1,2-a]benzimidazoles.

Two alternative synthetic approaches to new silicon-containing oligo(arylenevinylenes), 1,4-bis-{(E)-2-[4-(trimethylsilyl)phenyl]ethenyl}benzene and 9,10-bis{(E)-2-[4-(trimethylsilyl)phenyl]ethenyl}anthracene via Heck reactions of trimethyl(4-vinylphenyl)silane with the corresponding dibromoarenes and of (4-bromophenyl)trimethylsilane with the corresponding divinylarenes were studied. The reaction of 9,10-divinylanthracene with (4-bromophenyl)trimethylsilane was found to be accompanied by elimination of one trimethylsilyl group.

Some unique purine hydrazinylidene derivatives were synthesized by the regioselective reaction of 2,6-dichloropurine with hydrazine hydrate, followed by condensation with commercially available 1,3-dicarbonyl compounds according to a green chemistry approach. The structures of the synthesized compounds were confirmed by ¹H and ¹³C NMR, IR, and mass spectra and elemental analyses. The regioselectivity of chlorine substitution in 2,6-dichloropurine was established by HMBC (Heteronuclear Multiple Bond Correlation) NMR technique.

Novel Fe₃O₄/SiO₂/PPA nanoparticles were used as solid acid support in the solvent-free synthesis of 12-aryl-9,9-dimethyl-8,9,10,12-tetrahydro-11H-benzo[a]xanthen-11-ones via multicomponent condensation of aromatic aldehydes with naphthalen-2-ol and 5,5-dimethylcyclohexane-1,3-dione. The target products were obtained in good to high yields. The Fe₃O₄/SiO₂/PPA nanoparticles were thoroughly characterized by scanning electron microscopy, transmission electron microscopy, Fourier-transform IR spectroscopy, and energy-dispersive C-ray spectroscopy. The new catalyst has a high activity and is environmentally friendly, heterogeneous, easily recoverable, and recyclable without loss of catalytic activity.

A four-step procedure has been developed for the synthesis of (S)-3-isopropyl-1-[(R)-1-phenylethyl)- 1,4-diazaspiro[4.5]decan-2-one with high diastereoselectivity (up to 95% de) from (S)-α-aminoisovaleric acid (L-valine). Quantum chemical computations of the synthesized compound have been performed using Gaussian 09 software package.

4-Amino-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione was synthesized in three steps from carbon disulfide, hydrazine hydrate, and acetic acid. Its reaction with benzoyl isothiocyanates prepared from substituted benzoyl chlorides and ammonium thiocyanate afforded the corresponding N-benzoyl-N′-triazolyl-thioureas. The obtained compounds were screened for antibacterial activity against Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), and Pseudomonas aeruginosa (ATCC 27853). Their antibacterial activity against gram-positive bacteria was higher than against gram-negative bacteria, and derivatives containing electron-withdrawing groups were more active than those with electron-donating substituents.

8-Aroyl-3,4-dihydro-1H-pyrrolo[2,1-a][1,4]oxazine-1,6,7-triones reacted with 3-benzylamino-5,5-dimethylcyclohex-2-en-1-one to give 3′-aroyl-1-benzyl-4′-hydroxy-1′-(2-hydroxyethyl)-6,6-dimethyl-6,7-dihydrospiro[ indole-3,2′-pyrrole]-2,4,5′(1H,1′H,5H)-triones.

Reaction of 5-substituted 2-hydroxybenzaldehydes with 2-[3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene]propanedinitrile (tricyanofuran) in ethanol in the presence of ammonium acetate afforded 2-{3-cyano-4-[(E)-2-(2-hydroxyphenyl)ethenyl]-5,5-dimethylfuran-2(5H)-ylidene}propanedinitriles which were found to exhibit solid state fluorescence with the emission maxima ranging from λ 594 to 640 nm. Chromophores containing an alkyl substituent in the benzene ring showed the most intense fluorescence.