Том 54, № 8 (2018)

2,2′-[Ethane-1,2-diylbis(oxy)]bis[N-(anthracen-9-ylmethyl)ethanamine] and its bisphenylthiourea and bisthiourea derivatives have been synthesized. The diamine, being a certain analog of an aza-crown ether with an open chain, exhibits a 50 times increase in the relative fluorescence intensity (off-on process) in the presence of cadmium(II) cations. Bis(phenylthiourea) is a bifunctional fluorophore sensitive to mercury(II) cations (emission flaring) and fluoride anions (emission quenching). Anions F^–, CN^–, H₂PO₄^–, and AcO^– lead to a practically complete quenching of the fluorescent properties of the bis(thiourea) (off-on process).

A selective synthesis of (Z)-N-(adamantan-1-yl)carbamides by the reaction of adamantan-1-ol and nitriles in the presence of Cu catalysts was carried out. Z-Conformation of amides is established basing on X-ray diffraction analysis and 2D NMR data.

Synthesis of benzyl alkyl ethers was performed in high yields by intermolecular dehydration of benzyl and primary, secondary, tertiary alcohols under the effect of copper containing catalysts. The formation of benzyl alkyl ethers occurs with participation of benzyl cation.

Three-component synthesis of ethyl 4-aryl-2-methyl-5-cyano-6-(dicyanomethylidene)-1,6-dihydropyridine-3-carboxylates was developed consisting in the reaction of acetoacetic ester, aromatic aldehydes, and malononitrile dimer in the presence of sodium nitrite. Optical properties of synthesized compounds were investigated and it was demonstrated that they possessed intensive fluorescence in solution and in solid state with emission maxima in the yellow and green region of the visible light.

One-pot process was studied between a substituted 4-hydroxy-2Н-pyran-2-one and aromatic aldehydes and ammonium acetate in the conditions of modified Hantzsch reaction in acid environment under thermal and microwave activation. Arylmethylenebis-4-hydroxy-2Н-pyridin-2-ones, hydrochromenopyridinone, and their oxygen-containing heteroanalogs were isolated. A primary condensation was confirmed into bispyran-2-one adducts, and at the use of salicilaldehyde, into pyranochromene with subsequent recyclization of pyranone fragments in pyridinone ones.

For the first time decomposition was investigated of 4-alkoxy-5-amino-3-methylthiophene-2-carbonitriles under the conditions of electronic (70 eV) and chemical (reagent gas methane) ionization. At the electronic ionization the compounds under study [except for 4-(1-ethoxyethoxy) and 4-(ferrocenylmethoxy) derivatives] form stable molecular ions that decompose mainly by the cleavage of an alkyl radical from the alkoxy-substituent. Further fragmentation of the arising ion [M–Alk]⁺ depends on the substituent nature in the amino group. In the mass spectrum of 4-(ferrocenylmethoxy)-substituted thiophene peaks of the ion [FcCH₂]⁺ and its fragmentation products prevail. In the mass spectra of chemical ionization predominant peaks belong to ions M^+·, [M + H]⁺ and [M + C₂H₅]⁺, and fragment ions are absent.

Reaction of 1,2-diamino-4-nitrobenzene with furan-2-carbaldehyde in the presence of copper sulfate afforded 2-(furan-2-yl)-5(6)-nitro-1H-benzimidazole. Its N-methylation provided 1-methyl-5(6)-nitro isomers. After reduction of isomers with tin in conc. HCl a pure 3-methyl-2-(furan-2-yl)benzimidazol-5-amine was obtained. The condensation of this amine with acetic anhydride led to the formation of N-[3-methyl-2-(furan-2-yl)benzimidazol-5-yl]acetamide whose treatment with excess P₂S₅ in anhydrous pyridine resulted in the corresponding thioamide. The latter was oxidized with K₃[Fe(CN)₆] in alkaline environment to obtain 2,8-dimethyl-7-(furan-2-yl)-8H-imidazo[4,5-g][1,3]benzothiazole. Its reactions of electrophilic substitution were studied: nitration, bromination, sulfonation, formylation, acylation. The substituent is introduced exclusively in the position 5 of the furan ring.

Reaction of potassium thiocyanate with 2-[2-oxo-1-(1-tosyloxyimino)-2-phenylethyl]pyrimidin-4-(3H)-one derivatives led to the formation of a new fused heterocyclic system with a common nitrogen atom, substituted 7H-[1,2,5]thiadiazolo[2,3-a]pyrimidin-7-one.

Reactions of (2-aminophenyl)diphenylmethanol with ketones (dimedone, camphor, and 3-bromocamphor) in acetic acid result in the formation of arylimines of camphore and 3-bromocamphore, substituted tetrahydroacridin-1(2H)-one and 2-methyl-4,4-diphenylbenzoxazine.

Regiospecific reduction of carbonyl group of acyl chain in the previously described 4-nitro-3-arylbutanoyl derivatives of dimedone and cyclopentane-1,3-dione was performed. On the basis of nitromethyl group of the enol derivatives of the reduction products obtained from the mentioned compounds nitrile oxide intermediates were prepared, which in situ reacted with phenylacetylene to form the corresponding isoxazole derivatives.

One-pot convenient process was developed for the production of 3,5-disubstituted 1,2,4-oxadiazoles by reaction of amidoximes with anhydrides or acyl chlorides in a system NaOH‒DMSO. The reaction proceeds at room temperature with high yields.

Three-component reaction involving cyclopentane-1,3-dione, substituted benzaldehydes, and chloromethyl propyn(en)yl ethers results in a stereoselective formation of trans-1-aryl-2-{[prop-2-(yn)enyloxy]-methyl}spiro[2,4]hepta-4,7-diones in satisfactory yields.

Proceeding from 2,2′-disulfanediyldipyridine and isoeugenol a regioselective one-pot synthesis was developed affording 3-(4-hydroxy-3-methoxyphenyl)-2-methyl-2H,3H-[1,3]thiazolo[3,2-a]pyridin-4-ium chloride in a 70% yield.

Mercuration of a terminal triple bond in pirazoles and triazoles derivatives in the presence of acetylacetone followed by demercuration of intermediates by NaBH₄ afforded heterocyclic oxoenol derivatives.