M. V. Livantsov

Isoxazol-3-yl(Isothiazol-3-yl)-1,2,4-Triazoles, Tetrazoles, and -1,3,4-Oxadiazoles: Synthesis, Palladium Complexes, and Catalytic Applications

We used 5-arylisoxazole-3-carbonitriles and 4-R-5-chloroisothiazole-3-carbonitriles to prepare the corresponding (5-arylisoxazol-3-yl)- and (4-R-5-chloroisothiazol-3-yl)-1,2,4-triazoles, -tetrazoles, and -1,3,4-oxadiazoles. The obtained bis-heterocycles along with some of the intermediate monocyclic azoles formed palladium complexes that were highly active Suzuki reaction catalysts in aqueous and aqueous-alcohol media.

5-(Naphth-1-yl)- and 5-[(1,1′-biphenyl)-4-yl]isoxazole-3-carbaldehyde oximes: Synthesis, complexes with palladium, and application in catalysis

Abstract1-(Naphth-1-yl)- and 1-[(1,1′-biphenyl)-4-yl-3,4,4-trichloro-3-buten-1-ones were synthesized by acylation of naphthalene and biphenyl with 3,4,4-trichloro-3-butenoyl chloride. Further reaction with hydroxylamine led to 5-(naphth-1-yl)- and 5-[(1,1′-biphenyl)-4-yl]isoxazole-3-carbaldehyde oximes. The latter form complexes with palladium, which possess high catalytic activity in the Suzuki reaction in aqueous and aqueous-alcoholic media.

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.

TIN(IV) COMPLEXES WITH O-ETHYL(N-ETHYL-N, N-DIMETHYLAMMONIOMETHYL)PHOSPHONATE

Abstract O,O-Diethyl-(N,N-dimethylaminomethyl)phosphonate undergoes ethyl migration leading to O-ethyl-(N-ethyl-N,N-dimethylammoniomethyl)phosphonate (L). Several new complexes of tin(IV) and organotin(IV) chlorides with the title ligand have been synthesized. The stoichiometry of the obtained complexes is as follows: (R3SnCl)2 · L (R=Me, Bu, Ph), R2SnCl2 · L (R=Me, Bu, Ph), RSnCl3 L (R=Me, Ph) and SnCl4 · L. All the complexes have been studied in solution by means of 1H-, 13C-, 31P- and 119Sn-NMR spectroscopy. Their solid state structures have been investigated by means of Mossbauer spectroscopy and the molecular structure of the complex (Ph3SnCl)2 · L has been determined by X-ray crystallography. The ligand behaves as a bidentate ligand, bridging two pentacoordinate trigonal bipyramidal organotin moieties through an O–P–O fragment. The spectroscopic data for R2SnCl2 · L, RSnCl3 · L and SnCl4 · L suggest hexacoordinate structures with an octahedral tin environment, the complexes probably being polymeric according to the bridging ligand behavior.

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.

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.