To prepare novel biodegradable copolymers with functional substituents that are distributed statistically or randomly over the macromolecule chain and have improved characteristics compared to homopolymers, we conducted a series of synthetic experiments with a novel cyclic monomer, 5-(benzyloxy)-1,3-dioxepan-2-one (4). This compound was synthesized, and its homopolymer, as well as its copolymers with L-lactide, ε-caprolactone and trimethylene carbonate, were prepared in a polymerization solution with stannous octoate as the initiator. The formation of the copolymers was confirmed using NMR spectroscopy and DSC data. The distribution of the monomeric units of the substituted 7CC in the copolymers with L-lactide and ε-caprolactone is random, as it is close to a statistical distribution. The copolymer with TMC is a gradient copolymer due to the different rates of monomer polymerization. The copolymer with a composition of 10(ε-CL):1(carbonate 4) can be considered a promising polymer after the deprotection of the hydroxy group for the inoculation of the functional substituents due to its convenience of preparation and properties similar to those of poly(ε-caprolactone).

A convenient one-step method for the synthesis of new bisacridine derivatives, containing fragments of 5-arylisoxazoles, 4,5-dichloroisothiazole, as well as isonicotinic acid residues covalently attached by ester groups to various positions of the aromatic core, was developed. A three-component cascade condensation of 1,5-naphthalenediamine, aldehydes, and cyclic β-dicarbonyl compounds was carried out by refluxing in butanol. Quaternary ammonium salts of synthesized bisacridine derivatives were obtained. It was shown that the synthesized bisacridine compounds form complexes with palladium LPdCl2, which exhibit high catalytic activity in the model Suzuki reaction in water in the absence of organic co-solvent.

The new mono- and bis(aminomethylenediphosphonic) acids are synthesized for the first time via unique reaction of tris(trimethylsilyl) phosphite and various N-formyl amino alkanols or bis(N-formyl amino) alkanes at the presence of effective catalyst - trimethylsilyl triflate under mild conditions. The further treatment of initially formed trimethylsilyl intermediates with the methanol excess resulted in the crystalline mono- and bis(aminomethylenediphosphonic) acids in high yields. The catalytic scheme of target substances formation is proposed and discussed in detail. The structures of target acids were confirmed by the H-1, C-13, P-31 NMR spectra and high resolution mass spectra (HRMS). The resulting compounds are of great interest as perspective bioactive substances with versatile properties and effective polydentate ligands. (C) 2021 Elsevier B.V. All rights reserved.

A method for the synthesis of 5-arylisoxazole- and 4,5-dichloroisothiazole-3-carboxylic acids derivatives based on 4-acetyl- and 4-benzoylpyridine has been developed. Esters and amides were prepared by acylation of (pyridin-4-yl)methanols and (pyridin-4-yl)methanamines with acid chlorides of substituted 1,2-azole-3-carboxylic acids in ether or methylene chloride in the presence of triethylamine. Quaternary ammonium salts of synthesized pyridine derivatives were also obtained.

The new non-proteinogenic amino acids with methylenebisphosphonic acids moieties are synthesized for the first time via unique reaction of tris(trimethylsilyl) phosphite and various N-formyl amino acids at the presence of effective catalyst - trimethylsilyl triflate under mild conditions . The further treatment of initially formed trimethylsilyl intermediates with the methanol excess resulted in the water-soluble non-proteinogenic amino acids with methylenebisphosphonic acids moieties in high yields. The catalytic scheme of target substances formation is proposed and discussed in detail. The structures of target functionalized amino acids and their precursors were confirmed by the H-1, C-13, P-31 NMR spectra and high resolution mass spectra. The resulted compounds are of great interest as promising antiviral substances and effective ligands. (C) 2021 Elsevier B.V. All rights reserved.

The review examines methods for the preparation of compounds containing the 3H-pyrrolo[2,3-c]quinoline fragment, which have been published mainly over the past 10–15 years.

New methylamine derivatives with 1,2-azole fragments (phenylisoxazole, p-tolylisoxazole, 2,5-dimethylphenylisoxazole and 4,5-dichloroisothiazole) and their palladium complexes were synthesized. It was shown that palladium complexes with the obtained N-methyl-1-(1,2-azol-3-yl)methylamine exhibit high catalytic activity in the Suzuki reaction in aqueous medium.

The new convenient synthesis of functionalized aryl and pyridyl aminomethylenebisphosphonic acids and their derivatives has been developed via silicon-assisted methodology. New functionalized amino-methylenebisphosphonic acids containing pyridines moieties were obtained using unique reaction of tris(trimethylsilyl) phosphite with N-formyl aminopyridines and trimethylsilyl triflate as a catalyst under mild conditions. Intermediates - tetra(trimethylsilyl) aminomethylenebisphosphonates formed, were converted to the target acids by further treatment with methanol excess. In contrast the corresponding tetraethyl aminomethylenebisphosphonates were synthesized under heating (130 degrees C) of four component mixture (diethyl trimethylsilyl phosphite, triethyl orthoformate, aryl- or pyridylamine, and diethyl phosphite) in the presence of zinc chloride catalyst. The catalytic schemes of target substances formation are proposed and thoroughly discussed. (C) 2020 Elsevier B.V. All rights reserved.

The convenient silicon-assisted synthesis of new aminomethylenebisphosphonic acids and their precursors was developed via unique methodology. So new aminomethylenebisphosphonic acids with quinolines moieties were obtained using suitable reaction of tris(trimethylsilyl) phosphite and N-formyl aminoquinolines catalyzed by trimethylsilyl triflate under mild conditions (20 degrees C). The initially formed intermediates - tetra (trimethylsilyl) aminomethylenebisphosphonates are transformed to target acids by methanolysis in high yields. The catalytic scheme of target substances formation is proposed and discussed in detail. The structures of aminomethylenebisphosphonic acids and their precursors with substituted quinoline moieties were confirmed by the H-1, C-13, P-31 NMR spectra and high resolution mass spectra. (C) 2020 Elsevier B.V. All rights reserved.

N-(4,6-Dimethylpyrimidin-2-yl)-5-phenylisoxazole-3-carboxamide was used as a ligand for obtaining bimetallic boron-containing heterogeneous catalysts Pd–Ni(Co)–B–L (Ni(Co):Pd = 9:1). The obtained composites were highly active as catalysts of Suzuki reaction in aqueous media, allowing to develop convenient methods for the synthesis of heterobiaryls containing furyl and thienyl rings.

An efficient and high-yielding strategy to prepare "unsymmetrical" 4-aryl-isoxazol-3,5-dicarboxylic acid derivatives from nitroacetic esters and aromatic aldehydes has been developed. The strategy is based on the isolation and usage of the previously missed intermediate of the Dornow reaction-5-hydroxy-6-oxo-4-aryl-6H-1,2-oxazine-3-carboxylates. In addition, the mechanism of the Dornow reaction was partially revised.

The new functionalized aminomethylenediphosphonates with moieties of various amino acids are synthesized via unique reaction of tris(trimethylsilyl) phosphite and N-formyl amino acids at the presence of effective catalyst – trimethylsilyl triflate under mild conditions. The further treatment of aminomethylenediphosphonates with the methanol excess resulted in the water-soluble functionalized aminomethylenediphosphonic acids.

The convenient synthesis of new aminomethylphosphinic acids and their derivatives containing N-alkyl 4-hydroxypiperidines moieties was developed. The addition of bis(trimethylsiloxy)phosphine to N-alkyl 4-piper-idones proceeds under mild conditions to give PH-phosphinates as key compounds for preparation of trimethylsilyl esters of above acids via interaction with various aminals. The further treatment of phosphinic acids trimethylsilyl esters with the methanol resulted in the water-soluble corresponding acids. The structures of aminomethylphosphinic acids and their precusors 1-3 with substituted piperidine moieties were confirmed by the H-1, C-13, P-31 NMR spectra.

New types of (hydroxymethyl)phosphonic and (methylene)diphosphonic acids bearing heterocyclic fragments were synthesized by addition of tris(trimethylsilyl) phosphite to N-formyl derivatives of five-membered nitrogen heterocycles.

A simple and effective method on the basis of Fischer reaction in polyphosphoric acid is proposed for the synthesis of previously unknown heterocyclic structures that contain the 5-chloro-1H-pyrrolo[2,3-b]pyridine system. This method can be used for the synthesis of 3-substituted and 2,3-disubstituted 5-chloro-7-azaindoles with alkyl and aryl substituents.

The new functionalized hydroxymethylphosphonic and methylenediphosphonic acids are synthesized via unique reaction of tris(trimethylsilyl) phosphite and N-formyl N-heterocycles, N-substituted 4-piperidones, 3-quinuclidone, and 2-adamantanone at the presence of effective catalyst – trimethylsilyl triflate under mild conditions.

A simple and convenient procedure for the preparation of some unknown 2,3‐disubstituted 5‐iodo‐1 H ‐pyrrolo[2,3‐ b ]pyridines from readily available starting materials by Fischer indole cyclization in polyphosphoric acid is described. The present methodology provides an alternative synthetic approach to the synthesis of 5‐iodo‐7‐azaindole scaffold. All synthesized compounds were characterized by IR, MS, 1 H and 13 C NMR, and elemental analysis.