A. A. Prishchenko

UNUSUAL DIRECTION OF THE ARBUZOV REACTION OF DIALKOXYMETHYLPHOSPHONITES AND THEIR ANALOGUES

Abstract The alkylation and acylation reactions of dialkoxymethylphosphonites and their analogues have been studied. The Arbuzov rearrangement of these compounds was accompanied by the P[sbnd]C bond cleavage with retention of three-coordinate phosphorus atom.

Synthesis of (aminomethylene)bisphosphonic acid derivatives

Amino derivatives of methylenebisphosphonic acids were synthesized by phosphorylation of formamide, nitriles or hydrochlorides of alkyl imidates with H3PO3—PCl3—(Me3Si)2NH.

Syntheses of N-phenylaminomethylenediphosphonic and -diphosphinic acids and their derivatives

Substituted aminomethylene diphosphorus-containing compounds are of interest as prmising ligands and biologically active substances [1]. Some of compounds of this type can be obtained by suitable methods using dialkylformamide dialkylacetals [2]. Aiming to synthesize new N-aminomethylenediphosphorus compounds we examined a reaction of some of trimethylsilyl phosphites and hypophosphites taken in excess with the corresponding ethoxymethyleneimine I and formamidine IV obtained similarly to the earlier described procedures [3]. Thus, ethoxymethyleneimine I reacts with a mixture of diethyl(trimethylsilyl)phosphate and diethylphosphite and also with a mixture of tris(trimethylsilyl)phosphate and bis(trimethylsilyl)phosphate at 140–160oС to form diphosphonates II and III. In the zinc chloride catalyst is required for the preparation of compound III (cf. [4]). DOI: 10.1134/S1070363209090230

Synthesis of phosphorus derivatives of 2,6 -Di -tert -butyl -4 -methylphenol

Convenient procedures for the synthesis of 2,6-di-tert-butyl-4-methylphenol (ionol) mono-, di-and triphosphorus derivatives, starting from the readily accessible 3,5-di-tert-butyl-4-hydroxybenzaldehyde, are proposed, and some properties of the obtained compounds are presented.

A New Type of Aspartic Proteinase Inhibitors with a Symmetric Structure

Molecules of aspartic proteinases of mammalian and fungal origin are known to consist of one polypeptide chain forming two structurally similar domains.1–3 The molecules in whole possess pseudosymmetric structure with two-fold axis of symmetry. In contrast to cellular aspartic proteinases, the enzymes of retroviruses can function in the form of homodimers only.4,5 The active site is formed during dimerization so that each subunit contributes one Asp25 residue to the catalytic site. Thus the active molecule is perfectly symmetric. At the same time the substrates of the enzyme are not symmetric as peptide chains are always directed. So in the active site of a retroviral proteinase the productive binding of the substrate is possible both “from east to west” and vise versa, “from west to east”. X-ray analysis studies have revealed that binding of inhibitors and, most likely, substrates causes significant conformational changes in aspartic proteinases.6–8 In the case of HIV proteinase such changes were shown to disturb the symmetry of the molecule.9,10 But this may not be necessary in the case of binding of a symmetric inhibitor, and symmetric structures may have a significant advantage both in affinity and in selectivity, as the degree of symmetry is much higher for the viral enzymes compared to cellular ones.

Synthesis of new types of aminomethylenediphosphorus-containing acids and their derivatives

Convenient methods for synthesis of various aminomethylenediphosphorus-containing acids and their derivatives starting from available trimethylsilyl esters of hypophosphorous and phosphorous acids, ethoxymethyleneimine hydrochlorides, and N-substituted formamides have been proposed. Selected properties of the obtained compounds have been examined.

Complexes of organotin compounds with bis- and trisphosphonate derivatives of 2,6-di-tert-butylphenol having antioxidant activity

Complexes of organotin compounds R2SnCl2 with bisand trisphosphonate derivatives of 2,6-di-tert-butyl-4-methylphenol (ionol) were synthesized. X-ray diffraction studies were carried out for some of them. The redox properties of the synthesized compounds were characterized by cyclic voltammetry. Antioxidant/prooxidant activity of the complexes was studied using a new electrochemical method based on measuring the rate of hydrogen atom transfer to the stable radical 2,2´-diphenyl-1-picrylhydrazyl (DPPH). The data obtained were compared with the results of studying activity of the compounds during lipid peroxidation (LP) in biological samples. A correlation is observed between the results on antioxidant activity obtained by electrochemical DPPH test and using biological samples. Unlike the initial organotin compounds, the synthesized complexes have antioxidant activity, whereas phosphorus-containing phenols exhibit the properties of efficient antioxidants and chelating agents.

Addition of tris(trimethylsilyl) phosphite to N-substituted 4-piperidone

Convenient methods for the synthesis of functionalized phosphonic acids containing piperidine moieties via the reaction of tris(trimethylsilyl) phosphite with N-substituted 4-piperidone derivatives have been developed.

Synthesis of new aryl-substituted methylphosphonic and methylenediphosphonic acids and their derivatives

Simple and versatile synthetic procedures towards new aryl-substituted hydroxymethylphosphonic and methylenediphosphonic acids via reactions of either aromatic aldehydes or their derivatives with phosphites were elaborated.

New functionalized derivatives of mono- and diphosphonic acids substituted with five-membered nitrogen heterocycles

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.