SYNTHESE ET REACTIVITE D'UN ESTER CYCLIQUE D'α-AMINODIPHOSPHONATE. II

Abstract

The reactions of methoxy dioxaphospholan and corresponding hydrogen phosphonate 1 with (MeN = CHCl)Cl, (MeO)₂CHNMe₂ and MeOCH₂NMe₂ have been studied.

These reactions lead either to amino diphosphonate 5 or to amino phosphonate 3 and phosphate 2. The hydrolysis and methanolysis reactions of 5 are also presented.     

METALLAPHOSPHENES AND DIPHOSPHENES

Abstract

Transient metallaphosphenes (rbnd2;M[dbnd]P[sbnd]) have been obtained by exchange reactions between disilylphosphines and organometaldihalides (M = Ge, Sn), or by thermolysis of 2-metallaphosphetanes (M = Si, Ge). They are characterized by trapping reactions with strained heterocycles. The first stable germaphosphene 12 has been synthesized by dehydrohalogenation from the parent halogermylphosphine and isolated in form of orange crystals. It is very reactive toward compounds with active hydrogen.

Transient diphosphenes ([sbnd]P[dbnd]P[sbnd]) have been prepared by the same type of exchange reactions between disilylphosphines and dichlorophosphines and characterized by trapping reactions on dienes. The second stable diphosphene 18 has been obtained by addition of t-BuLi on trisyldichlorophosphine. Its structure has been determined by X-ray diffraction and some aspects of its reactivity are described. The reaction of bisyltrichlorogermylphosphine with DBU affords the new stable and potentially reactive diphosphene 30.     

New Sulfur and Phosphorus Containing Metal Complexes on the Basis of Trithiophosphites. Synthesis and Properties

Abstract

New sulfur- and phosphorus containing metal complexes have been obtained by means of reactions of trialkyl- and triaryltrithiophosphites with transition metal halides. Their reactions with proton containing and carbonyl compounds have been studied.     

The Chemistry of Thioloderivatives of Trivalent Phosphorus Acids

Abstract

The substitution and addition reactions have been studied in the series of thioloderivatives of P(III) acids. The reactions have been shown to proceed with the rupture of the P-S bond, the phosphorus coordination being preserved.     

New Derivatives of 1,2-Alkadienephosphonic Acids

Abstract

The preparations of new cyclic derivatives of 1,2-alkadienephosphonic acids have been reported and the reactions of these compounds with bromine have been investigated.     

REACTIONS OF ARYLSULPHONYL FLUORIDES

Abstract

Substituent effects have been investigated for both nucleophili -ic and reduction reactions of arylsulphonyl fluorides in aqueous media. The significance of the results will be discussed in relation to the reactions of arylsulphonyl chlorides.     

Bestimmung der Extraktionskonstanten der Tellur-Pyrasolindithiocarbaminate

Abstract

In this work the exchange reactions between the ion Te(IV) in the aqueous phase and the aryl substituted pyrasolindithiocarbaminates of zinc into chloroform have been investigated. The equilibrium (exchange) constants of these reactions have been determined experi mentally. The extraction constants and two-phase stability constants of Te(PDTC)₄ have been calculated.     

SOME SULFUR AND NITROGEN SUBSTITUTED XYLOQUINONES

Abstract

This paper reports reactions of dihalogeno-xyloquinone with sulfur and nitrogen nucleophiles, leading to the di-and mono-substituted derivatives, respectively. The mixed nitrogen-sulfur and carbon-nitrogen derivatives were also synthesized. New reactions, oxidation of dimethylthioxyloquinone to yield a mono-sulfinyl derivative and treatment of the latter with thionyl chloride, are described.

Although dihalogeno-xyloquinones are known compounds^{2a, b} their reactions with sulfur and nitrogen nucleophiles have not been reported. These reactions seemed to be of interest in view of potential biological activity of the expected thio-and amino-substituted xyloquinones, in comparison with the naphthoquinone and benzoquinone analogues.³     

A NOVEL REDUCTIVE CYCLIZATION OF ARYLMETHYLIDENEMALONONITRILE PROMOTED BY LOW-VALENT TITANIUM

ABSTRACT

The intermolecular and intramolecular reductive coupling reactions of arylmethylidenemalononitriles induced by low-valent titanium have been studied. A possible reaction mechanism is proposed.     

DFT study on the regio- and stereoselectivity of the organocatalytic aza-Diels-Alder reaction of crotonaldehyde and cyclic 1-aza-1,3-butadiene

The mechanism of 1,4-, 1,2-, and 3,4-cyclization reactions of cyclic 1-azadiene 1 with an organocatalyst 4 has been studied theoretically using DFT method. The reactions proceed in a stepwise fashion, with zwitterionic intermediates. The most favorable cyclization reaction takes place along the C–C pathway of the 1,4-cyclization reaction, under a combination of kinetic and thermodynamic control. The reaction is characterized by the nucleophilic attack of 4 (C₅) to the electrophilic center of 1 (C₁), leading to the formation of cycloadduct 6, which correctly explains the source of the regioselectivity.

     

SOME COMPLEXES OF AROMATIC ORTHO-BIS(METHYLTHIO)ETHERS

Abstract

The reactions of some partially fluorinated aromatic ortho-bis(methylthio)ethers with various metal ions and metal carbonyls have been examined. All the complexes formed have been characterized.     

Thermodynamically and Kinetically Controlled Metallation Reactions on Aminomethylphophines

Abstract

The reaction of different substituted dimethylamino methyl phosphines with strong bases, and the following reactions of a number of carbanions obtained, have been investigated.     

Phosphoryl and Thiophosphoryl Transfer Reactions: Stereochemical Imperatives for Metaphosphate and Thiometaphosphate

Abstract

The stereochemical courses of phosphoryl transfer reactions in aprotic solvents and thiophosphoryl transfer reactions in protic solvent have been determined. The extensive racemisation observed in both instances is discussed in terms of metaphosphate and thiometaphosphate intermediates of significant life-times.     

EXTRUSION OF SULPHUR DIOXIDE FROM CYCLIC SULPHUR COMPOUNDS

Abstract

The fragmentation of cyclic sulphur compounds such as (1) to (4) by photolysis and flash vacuum thermolysis will be discussed. Many of these reactions have been shown to be synthetically useful. The mechanisms of some of these reactions have been studied in some detail. The use of novel thermolytic and photochemical apparatus will be demonstrated.     

Synthesis of Phosphorylated Derivatives of Enamino-Carbonyl Compounds

Abstract

The reactions of enaminocarbonyl compounds (1) with phosphorylisocyanates have been investigated. Experiment established that the reactions with the participation of amino group and (or) C-2 atom form respectively ureas (2) and (or) their vinylogs (3) depending on the structure (1) i.e. the reactions proceed in two competitive directions.     

Selective chemical reactions in supercritical carbon dioxide,water, and ionic liquids

Abstract

Alternative solvents such as supercritical carbon dioxide, water, and ionic liquids are receiving an increase of interest as better replacements for conventional solvents in chemical reactions. They have been called sustainable green solvents because they are highly promising reaction mediums for organic synthesis. This review presents an overview of some selected chemical reactions that have been developed in these green solvents with a particular emphasis on metal-catalyzed reactions.     

Spectrophotometric Determination of Diphenylamine,Pyrrole, and Indole - A Kinetic Study

Abstract

The use of p-dimethylaminocinnamaldehyde (p-DAC) has been described for the colorimetric determination of diphenylamine (DPA), Pyrrole (Py) and Indole (In) in acidic media. The kinetics of the reactions were studied and a mechanism for the reactions has been proposed. The reaction products were isolated, and identified using IR, NMR and elemental analysis.     

REACTIONS OF TETRAPHOSPHORUS DECASULFIDE AND LAWESSON'S REAGENT WITH SILANES CONTAINING A FEW Si-O BONDS

Abstract

The reactions of tetraphosphorus decasulfide and Lawesson's reagent with tetra-, tri- and dialkoxysilanes were studied. On the basis of these reactions, new S-silyl esters of phosphorus(V) thioacids have been prepared. The prepared compounds were identified by IR, ¹H, and ³¹P NMR and mass spectra as well as elemental analyses.     

A NOVEL METHOD FOR THE PREPARATION OF SUBSTITUTED 5-AMINO-1,2,3, 4-THIATRIAZOLES BY AZA-TRANSFER REACTION

Abstract

Recently, the aza-transfer reactions between amino or hydrazino compounds and aryldiazonium salts or heterocyclic diazo compounds have been studied. In general, a mixture of different products is formed.     

An efficient method for Knoevenagel condensation: a facile synthesis of 5-arylidenyl 2,4-thiazolidinedione

Abstract

Knoevenagel condensation of various aromatic aldehydes with 2,4-thiazolidinedione has been carried out in polyethylene glycol-300. The reactions were carried out at moderate temperature with very simple isolation procedure and with better yields.