Showing papers in "Phosphorus Sulfur and Silicon and The Related Elements in 2001"

Chemical shiw prediction of 31p-nmr shifts for dialkyl or diaryl phosphonates

Abstract: A method for the determination of 31P NMR chemical shift has been developed for dialkyl and diaryl phosphonates. Increment values of functions in the vicinity of the phosphorus atom have been calculated by multi-linear regression with “Systat”.

A facile synthetic approach to dimethyl 2-arylamino-3- (triphenylphosphoranylidene) succinates from electron-poor primary arylamines

Abstract: A one-step synthesis of dimethyl 2-arylamino-3-(triphenylphosphoranylidene)succinates in fairly good yields by the reaction of electron-poor primary arylamines, dimethyl acetylenedicarboxylate and triphenylphosphine is reported. The structures of these compounds were confirmed by UV, IR, MS and 1H, 31P and 13C NMR spectroscopy, and elemental analyses. The NMR spectra indicated that the compounds (CDCl3 ah solvent) contained two rotamers with unequal population for each ylide.

Supramolecular Self-Assembly Through Secondary Bonds in Organotellurium Chemistry

Abstract: The solid state structures of organotellurium compounds, associated through secondary bonds, are presented in the light of supramolecular chemistry principles. Supramolecular self-assembly through secondary bonds occurs in organotellurium-nitrogen. -oxygen, -sulfur and -halogen compounds and leads to the formation of discrete supermolecules (e.g. dimers or tetramers) or infinite supramolecular arrays.

Monodealkylation des esters phosphoniques synthese de monosels et de monoacides phosphoniques

Abstract: Ce memoire decrit la synthese et la caracterisation principalement par RMN du 1H et 31P de monosels et de monoacides a partir de divers phosphonates porteurs de groupements alkyles de C1a C18 ou de groupements alkylenes (allyl et vinyl). Nous avons egalement utilise des composes fonctionnels porteurs d'alcool ou d'acetate et les resultats montrent la selectivite de la reaction. La methnde utilisee met en œuvre I'iodure de sodium dans des cetones (acetone ou butan-2-one) a reflux. Cette methode est tres selective quant a I'obtention du monosel, mais pratiquement seuls les esters methyliques sont reactifs. A I'aide d'une resine (sulfonique acide) echangeuse de cation on obtient I'acide correspondant avec un rendement quantitatif. This paper describes the synthesis and the characterization by 1H and 31P NMR of several monosalts and monoacids issued from phosphonates bearing alkyl groups (C1 to C18) or alkylene groups (allyl or vinyl). Functional compounds (alcohol or acetate) were also used and the ...

One-step, three-component synthesis of dialkyl 2-(imido-n-yl)-3-(triphenylphosphoranylidene) butanedioates

Abstract: A one-step synthesis of dialkyl 2-(imido-N-yl)-3-(triphenylphosphoranylidene)butandioates in fairly good yields by the reaction of imides, dialkyl acetylenedicarboxylates and triphenlphosphine is reported. The structures of these compounds were confirmed by IR, MS and 1H, 31P and 13C NMR spectroscopy, and elemental analyses. The NMR spectra indicated that the compounds (CDCl3 as solvent) contained two rotamers with unequal population for each ylide.

Synthetic and biological studies on coumarin hydrazone derivatives

Abstract: The reaction of both of coumarin and 6-nitrocoumarin hydrazones (1,4) with alkyl(aryl)isothiocyanate afforded the corresponding 3-N[alkyl(aryl)thioamido] coumarins 3a-d or benzopyrano[2,3-c]pyrazole-3-thione derivatives 6a-d , respectively. Compounds (3a-d) were used as key intermediates for the preparation of benzopyrano-pyridine derivatives (7a-d & 10a) or benzopyranoazepine derivatives 8a,c & 12a-d through the reaction with different acyl halides or ethoxymethylenemalononitriles and subsequent cyclization. Biological activity of some new compounds against Gram +ve and Gram -ve were given.

Diorganotellurium(IV) Dihalides and Secondary Bonding: Revisiting the Coordination Polyhedra

Abstract: The coordination geometry of the central atom in diorganotellurium(IV) halides, almost invariably described as ψ- trigonal bipyramidal, is in fact much more diversified. If intra and intermolecular secondary bonds and electron lone pairs are considered ψ-trigonal bipyramidal, ψ-octahedral, ψ-pentagonal bipyramidal and some others coordination geometries can be identified. A careful reexamination of a number of published structures is presented, with the analysis of the coordination polyhedra.

Synthesis and antifungal activity of some new miscellaneous s-triazoles

Abstract: The reaction of aryloxyacetic acid with thiocarbohydrazide under condition of fusion gave the corresponding s-triazole derivatives 2a-c. The dicyano derivatives 3, 4 were obtained via reaction of compound 2c with [bis(methylsulfanyl)methylidine]malononitrile and/or ethoxymethylenemalononitrile. Interaction of compound 2c with bromomalononitrile yielded the corresponding triazolothiadiazine derivative 5. In addition reaction of compound 2c with phenyl isothiocyanate furnished triazolothiadiazole derivative 6. Fusion of arylaminoacetic acids 8, 9 with thiocarbohydrazide afforded s-triazole derivatives 10, 11, respectively. The reaction of benzylthioacetic acid 12 with thiocarbohydrazide yielded the triazole derivative 13, When cyanoacetic acid 14 was reacted with thiocarbohydrazide the pyrazolotriazole derivative 16 was obtained. Some of the obtained compounds showed remarkable antifungal activity comparable to the fungicide Mycostatine.

Organophosphorus compounds as potential fungicides. part vi.1 preparation, characterization, and biological activity of analogues and derivatives of 1-aminopropanephosphonic acid

Abstract: α-Aminopropane-phosphonous,-methylphosphinic, and-phenylphosphinic acids do not exhibit comparable antifungal activity to that shown by α-aminopropanephosphonic acid (ampropylfos) against Drechslera teres, when applied as seed dressings. It is concluded that the phosphonic acid function is necessary for this type of activity. Moderate activity against several organisms was nevertheless shown by α-aminopropane-and α-aminoethane-phosphonous acids in foliar spray tests, although longer chain compounds were found to be inactive, α-Ureidopropanephosphonate (ammonium salt) also showed activity in foliar tests at 1000 ppm. A range of new ureylene-and thioureylene-bisphosphonates, prepared as potential profungicides of ampropylfos, proved to be inactive as seed dressings although tetrakis(2,2,2-trifluoroethyl) thioureylenebis(1-propylphosphonate) gave 75–100% control of Puccinia recondita as a foliar spray (1000 ppm). Characterization of the various compounds by nmr spectroscopy and mass spectrometry is ...

α-AMINO ACID DERIVED BISPHOSPHONATES. SYNTHESIS AND ANTI-RESORFTIVE ACTIVITY

Abstract: Eleven new bisphosphonates were prepared from naturally-occurring 1-amino acids. The synthesis required special attention to amino and side-chain protections. The novel compounds were tested in TPTX (thyroparathyroidectomized) rats against arotinoid-induced hypercalcemia and were compared to alendronate. Most of the compounds showed moderate to no anti-resorptive activity. Two compounds were more active than clodronate, but less than alendronate. Limited SAR conclusions were drawn.

Bisphosphonate prodrugs. synthesis and identification of (1-hydroxyethylidene)-1,1-bisphosphonic acid tetraesters by mass spectrometry, nmr spectroscopy and x-ray crystallography

Abstract: The preparation and identification of symmetric, H3CC(OH)[P(O)(OR)2]2, where R˭Me, Et, Pri, Ph, and non-symmetric, H3CC(OH)[P(O)(OR)1)(OR2)][P(O)(OR3)(OR4)], where R1˭Me, R2˭R3˭R4˭Ph; R1˭R2˭R3˭Ph, R4˭Me; R1˭R3˭Me, R2˭R4˭Ph; R1˭R2˭Et, Pri, Ph and R3˭R4˭Me; Tetraester derivatives of etidronate have been studied. Compounds were prepared from HP(O)(OR1)(OR2) and AcP(O)(OR3)(OR4) species under reflux. Mechanism studies have been made using HP(O)(OCD3)(OPh) and AcP(O)(OMe)(OPh) as starting materials. 1H, 13C, 31P NMR data and the MS fragmentation data in the gas phase are reported. The solid-state structures are given for three of the compounds, where R˭Et, Ph and R1˭R2˭Ph, R3˭R4˭Me.

A facile one-pot synthesis and antibacterial activity of aziridines and thiazines from 1,3-diarylprop-2-enones

Abstract: The title compounds 1a,b as examples for acyclic alkenones were utilized for the synthesis of some heterocycles namely, thiazines 2a,b and 3a-d, pyrimidines 4a,b. aziridines 7a,b. The unexpected tribromides 8a,b, obtained from bromination of 1a,b, were readily used to afford the pyrazoles 9a,b and isoxazoles 10 a,b. Biological screening of some selective synthesised compounds was determined in vitro using Gram-negative and Gram-positive bacterial strains.

Beiträge zur chemie von vinylphosphonsäurederivaten

Abstract: Vinylphosphonsauredichlorid I sowie dessen Thioanalogon 3 wurden mit Dialkylaminotrimethylsilanen Me3SiNR2 (R = Me. Et) zu den entsprechenden Amidchloriden CH2=CHP(:O)CI(NR2) 5 (R = Me) und 6 (R = Et) sowie den Thioamidchloriden CH2=CHP(:S)CI(NR2) 7 (R = Me) und 23 (R = Et) umgesetzt. Analoge Alkoholysereaktionen lieferten die ethoxy- und phenoxysubstituierten Esterchloride CH2=CHP(:O)CI(OR) 10 (R = Et) und 12 (R = Ph); auserdem erhalt man durch Veresterung mil aromatischen Diolen wie Tetrachlorbrenzkatechin oder 1,2-Dihydroxynaphthalin Diester. Sowohl die erwahnten Amidchloride ah auch die Ehterchloride wurden in einem weiteren Schritt durch Chlor-Fluo-raustausch mit SbF3 bzw. AsF3 in die entsprechenden Amidfluoride bzw. Thioamidfluoride CH2=CHP(:X)F(NMe2) 8 (X = O) bzw. 9 (X = S) und die Esterfluoride CH2=CHP(:O)F(OR) 11 (R = Et) bzw. 14 (R = Ph) uberfuhrt. Schlieslich wurden weitere Vinylphosphonsaurederivate, wie z.B. die vinylsubstituierte, cyclophosphamid-analoge Verbindung 21 durch Amino-l...

Synthesis of Novel Phosphonotripeptides Containing Uracil or Thymine Group

Abstract: In order to search for highly active aniicancer and antiviral agent, a new type of novel phosphonotripeptides containing a uracil or thymine group was synthesized by means of two-step peptide coupling reaction with DCC as the dehydrating agent and N-hydroxysuccinimide as the activating agent of the carboxyl group All products were characterized by 1HNMR, 31PNMR, IR spectra, and elemental analyses The results of bioassay show that compound 8 g possesses potential anticancer activity

Conversion of 3-aryl-5-phenyl-2(3h)-furanones into 3(2h)-isothiazolone derivatives

Abstract: Upon heating 3-aryl-S-phenyl-2(3H)-furanones (la-c) with benzylamine at 100°C in the absence of solvents, ring opening occurred with the formation of the corresponding N-benzylamides (3a-c). When the latter compounds (3a-c) were allowed to react with thionyl chloride at room temperature, the corresponding isothiazolones (4a-c) were obtained. Treatment of the isothiazolones (4a-c) with sodium hydroxide in benzene at room temperature affected debenzoylation to give the corresponding 2-benzyl-4-aryl-3(2H)-isothiazolones (5a-c).

Synthesis, reactions and conformational analysis of 5-arylidene-2-thiohydantoins as potential antiviral agents

Abstract: (Z)-5-Arylidene-1-(4-methylphenylsulfonyl)-2-thiohydantoins 5a,b were synthesized from the direct condensation of the aromatic aldehydes 4a,b with 1-(4-methylphenylsulfonyl)-2-thiohydantoins 3a,b. Compounds 5a,b were coupled with 2′-deoxy-3′,5′-di(4-methyl-benzoyl)-α-D-erythro-pentofuranosyl chloride 6 under alkaline conditions to afford N3-protected nucleosides 7a,b. Reaction of 5a,b with chloromethyl methyl sulfide and/or 2-bromoacetaldehyde diethyl acetal in alkaline medium afforded N3-alkyl derivatives 8a-c. Reaction of 5a with 1,2-dichloroethane in alkaline conditions afforded bis-thiohydantoinylethane 9a,b. Compounds 5a,b were condensed with formaldehyde and secondary amines to afford 3-aminomethyl-2-thiohydantoins derivatives 10a-d. On the other hand, reaction of unsubstituted 2-thiohydantoins derivatives 11b,c with chloromethyl methyl sulfide afforded the mono- and bis-methylthio derivatives 12a,b and 13a,b, respectively. Reaction of 11b,c with secondary amines and formaldehyde gave 3-ami...

Some cyclization reactions with 4-thiohydantoin: synthesis of some novel thiopyranoimidazoles, thienoimidazoles and imidazoquinolines and some metal complexes with biological interest

Abstract: 4-Thiohydantoin (II) with chloroacetic acid, chloroacetanilides and cyanothioformamides gave thieno[2,3-d)imidazoles (IV, V and IX), respectively. α,β-Unsaturated nitriles and anthranilic acids reacted with (II) to produce thiopyrano[2,3-d]imidazoles (III) and imidazo[4,5-b]quinolines (VII). Some metal complexes were prepared and the antimicrobial activity of some selected compounds was also reported.

Cyclic Chalcogenides Containing Group 13–15 Elements

Abstract: Novel cyclic polychalcogenides containing a variety of heavier main group elements of groups 13, 14, and 15 as ring members have been synthesized as stable crystalline compounds by taking advantage of an effective steric protection group, 2,4,6-tris[bis(trimethylsilyl)methyl]-phenyl (denoted as Tbt in this article). The molecular structures of tetrachalcogenametallolanes of group 14 elements, Tbt(R)ME4 (M = Si, Ge, Sn, and Pb; E = S, Se), and some polysulfides containing antimony or boron atom as a ring member were analyzed by X-ray crystallography to elucidate the skeletal features of these novel ring systems. Dechalcogenation reactions of these cyclic polychalcogenides with trivalent phosphorus reagents provide new and useful synthetic methods for the doubly bonded compouds between the corresponding heavier main group element and a chalcogen atom, a novel class of low-coordinate compounds in the main group element chemistry.

ACTION DESIMINES SUR LES MONOCHLOROPHOSPHINES: NOUVELLE VOIE D'ACCES A DES CETONES β-PHOSPHORYLEES

Abstract: The reaction of imines 1 with monochlorophosphines leads to β-phosphorylketones obtained in the ketonic 2 or enolic forms 2′. The structure of all obtained products is confirmed by NMR and IR spectroscopy.

Deoxygenation of sulfoxides to thioethers by molybdenum pentachloride (mocl5) and reductive coupling of sulfonyl chlorides to disulfides

Abstract: Molybdenum pentachloride (MoCl5) in the presence of Nal in dry acetonitrile or zinc powder in anhydrous THF converts sulfoxides to their thioethers in high yields. Sulfonyl chlorides can b...

THE PHOSPHATE-PHOSPHONATE AND PHOSPHONATE-PHOSPHATE REARRANGEMENTS AND THEIR APPLICATIONS - 7[1]: USE OF t-BUTYL AS PROTECTING GROUP AND SYNTHESIS OF CHIRAL, NONRACEMIC α-HYDROXYPHOSPHONATES

Abstract: The regioselectivity of metallation of hexyl diisopropyl phosphate (1) depends on the solvent, the temperature, and the base used. The best results are obtained with s-BuLi/TMEDA in hexane and diethyl ether at -78°C. the CH2O group being deprotonated preferentially over the CHO group (3:1 versus 2,5:1). The intermediate phosphonyloxy-substituted alkyllithiums (±)-4 and (±)-5 rearrange to phosphonates (±)-6 and (±)-7, respectively. The isopropyl groups can be replaced by t-butyl groups to direct metallation exclusively to CH2O. Homochiral diamines in place of TMEDA give chiral, nonracemic α-hydroxyphosphonates.

31p nuclear magnetic resonance spectroscopy of polyphenol-containing olive oil model compounds

Abstract: Phosphitylation of the free hydroxyl and carboxyl groups of a series of polyphenol-containing olive oil model compounds with 2-chloro-4,4,5,5-tetramethyl-dioxaphospholane allows their classification on the basis of 31P NMR chemical shifts. Unambiguous assignment of the 31P NMR chemical shifts of the dihydroxy- and polyhydroxy-phenols has been achieved by employing one and two-dimensional NMR techniques. Furthermore, integration of the appropriate signals of the hydroxyl derivatives in the corresponding 31P NMR spectra allows the quantification of these compounds. This study forms the basis for the development of a novel and sensitive method that can be used to obtain valuable information about polyphenols that are present in olive oils.

Synthesis of some new cyclic aminophosphonates and their physiological activities

Abstract: The synthesis of 19 newly synthesized cyclic aminophosphonic acid derivatives was described and their biological activity studied. It was found, as in the case of the previously described series of acyclic analogues, that the phytotoxicity of the compounds, tested on aquatic plant Spirodela oligorrhaza depended mainly on their hydrophobic parameters. The most pronounced phytotoxicity, the measure of which was concentration of aminophosphonates causing 50% inhibition of plant growth (EC50), exhibited compounds with not too long hydrocarbon substituent on the nitrogen atom (8–10 carbon atoms) and branched propyl groups on the phosphorus atom. The test had preliminary character and permitted to eliminate the less promising compounds for further studies.

Thio- and Selenoborates: from Rings to Clusters and Networks

Abstract: We herein present an overview on the structural diversity of thio- and selenoborates showing the development from molecular boron chalcogen compounds to layered and polymeric structures on one side and to boron cluster compounds on the other side.

Silica Chloride (Sio2-Cl) Promotes Highly Efficient Transformation of Acylals to Dithianes, Dithiolanesm, and Oxathiolanes

Abstract: Acylals react with 1,3-propanedithiol, 1,2-ethanedithiol and 2-mercaptoethanol in the presence of silica chloride to give 1,3-dithianes, 1,3-dithiolnnes and 1,3-oxathiolanes in excellent yields in CH2Cl2 at room temperature. It has been observed that acylals were more reactive than their aldehydes hut less reactive than acetals and ketals. Also aliphatic acylals survive under these conditions.

An Efficient One-Pot Synthesis of Sulphur-Containing Phosphorus Ylides

Abstract: Protonation of the reactive 1:1 intermediate produced in the reaction between dialkyl acetylenedicarboxylates and triphenylphosphine by arylsulfonamides leads to vinylphosphonium salts, which undergoes Michael addition with the conjugate base of the NH-acid to produce highly functionalized, salt-free phosphorus ylides in good yields. These stable ylides exist as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond, resulting from conjugation of the ylide moiety with the adjacent carbonyl group.

Comparative DFT Study of Group 13–15 Rings: Structure, Bonding and Thermochemistry

Abstract: Dimeric inorganic rings [X2MYH2]2 and [XMYH]2 (X=H,F,Cl,Br,I; M=Al,Ga,In; Y=N,P,As) and related monomer compounds X2MYH2, XMYH were theoretically investigated at B3LYP /LANL2DZP level of theory. Optimized structures and standard thermodynamic parameters of gas phase dissociation reactions were obtained. Nitrogen and Al-containing rings have higher stability compared to P,As and Ga,In systems; substituents X have minor effect on M-Y dissociation energy. [X2MNH2]2 dimers are stable in the gas phase up to 1100–1300K.

Selective phosphorylation on primary alcohols of unprotected polyols

Abstract: The triad tribenzylphosphite-iodine-pyridine offers a general selective method for phosphorylation reactions of primary alcohols of unprotected α-diols and polyols. A mechanistic study by 31P NMR allowed to evidence the formation, from iododibenzyl phosphate and pyridine, of a very reactive pyridinium salt intermediate. This analysis shows that pyridine behaves as a covalent catalyst like DMAP in acylation reactions from acylchloride. Due to its steric hindrance and high reactivity, this species appears to be the efficient selective phosphorylation reagent but leads to dibenzylphosphoric esters. Under mild conditions, the cleavage of benzyl groups gives monoester phosphoric acid.

On Perfluoroalkyl Tellurium Compounds

Abstract: This paper summarizes the present state of the preparations and chemical properties of perfluoroalkyl, mainly trifluoromethyl tellurium compounds. Te(CF3)2 is a reactive educt for trifluoromethyl transfer reactions in inorganic and organic syntheses. CF3TeTeCF3 is used as a starting material for preparations of CF3Te compounds, e.g. Hg(TeCF3)2, CF3Tel. The pyrolysis of (CH3)3SnTeCF3 gives difluoro telluroketone. Te(CF3)2 is easily oxidized to yield trifluoromethyl tellurium(IV) derivatives. The preparations and properties of many compounds of the composition (CF3)2TeX2 are described. Nucleophilic trifluoromethylation of (CF3)2TeCl2 yields tetrakis(trifluoromethyl) tellurium(IV).

Tris[(5-chloro-2-thienyl)methyl] phosphine oxide from elemental phosphorus and 2-chloro-5-(chloromethyl) thiophene

Abstract: White phosphorus readily reacts with 2-chloro-5-(chloromethyl)thiophene under phase-transfer conditions (KOH, water, dioxane, benzyltriethylammonium chloride, 50–52°C, 3 h) to form tris[(5-chloro-2-thienyl)methyl]phosphine oxide in good yield. This new phosphine oxide undergoes the Wittig - Homer reaction with benzaldehyde (NaNH2/THF system) leading to 2-chloro-5-|(E)-2-phenylethenyllthiophen and bis[(5-chlom-2-thienyl)methyl]phosphinic acid.