Reaktion von Alkyl- und Arylchlorsilanen mit Phosph(III) en-imidamiden

The reaction of RSiCl₃ (R=CH₃, C₂H₅, C₆H₅) and R₂SiCl₂ (R=CH₃) with one mole of the phosphenimidous amides R₂N–P=NR [R=R=Si(CH₃)₃; R=Si(CH₃)₃, R=C(CH₃)₃] yieds a four membered PN₂Si-ring system under elimination of (CH₃)₃SiCl.     

Rhenium(V) complexes with vinyl amides

Summary The reactions oftrans-ReOCl₃(PPh₃)₂ with vinyl amides such as RCOCH=C(R)NH₂, where R = CH₂CH₂CO₂H and R = Ph and C₆H₁₃; or R = Me, CH₂CH₂CO₂Me and R = Ph, give complexes of the type ReOCl₂-[RC(O^–)=CHC(R)=NH]PPh₃, the coordination geometry of which have been deduced from i.r. and¹H n.m.r. spectroscopic data.     

Acetoxy derivatives of trans-1,2-disilylethylene and their hydrolysis

Conclusions A method was developed for the synthesis of acetoxy-trans-1,2-disilylethylenes of formula (CH₃COO)_n(CH₃)_2–nRSiCH=CHSi(CH₃)R(OCOCH₃), where R and R=alkyl, and n=0 or 1. The corresponding silanols were obtained by the hydrolysis of the latter.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1395–1397, June, 1976.     

Telomerization of acrylic monomers with iodoform

Conclusions Together with dimethylformamide, iron pentacarbonyl initiates the telomerization of acrylonitrile, methyl acrylate, and methyl methacrylate with iodoform, resulting in the formation of telomeric homologs of the series CHI₂(CH₂CRI)_nR and CHI₂(CH₂CHR)_nR (n=1, 2; R=H, CH₃; R=CN, COOCH₃).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2284–2287, October, 1985.     

Reaction of α,α,ω-trichloro- and α,α,α,ω-tetrachloroalkanes with alkali metal acylates in aprotic solvents

Polychloroalkanes and -alkenes R(CH₂)_nCl (R=CHCl₂CH₂, CCl₂=CH, n=1, 3) in dipolar aprotic solvents — dimethylformamide (DMF), dimethylsulfoxide (DMSO), hexamethylphosphoramide (HMPA) — at 130–150°C react selectively at the CH₂Cl group with salts of carboxylic acids RCO₂K(Na) to form dichloroesters RCO₂· (CH₂)_nR (R=CHCl₂CH₂, CCl₂=CH). In tetrachloroalkanes CCl₃CH₂(CH₂)_nCl (n = 1, 3, 5) under the same conditions the selectivity of the CCl₃ and CH₂Cl groups relative to the nucleophile RCO₂K(Na) is altered — unsaturated esters RCO₂(CH₂)_nCH=CCl₂ are formed in one stage with yields of 75–90%. Under the selected conditions, high conversion of polychloroalkanes to esters is attained 3 to 5 times more rapidly than in acid media. The structure of the ester obtained has been confirmed by their PMR spectra.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2790–2793, December, 1990.     

Preparation of organocyclosilazanes by ammonolysis of dialkyldichlorosilanes

A study is made of ammonolysis of dialkyldichlorosilanes of the RR'SiCl₂ series, where R = Me, Et, and R = Me(CH₂)_n (n = 1, 3, 5, 7, 8). With the lower members of the homologous series it takes place in accordance with a previously known equation. Ammonolysis of dialkyldichlorosilanes with big R radicals on the silicon atom gives both cyclic and linear ammonolysis products.     

Enthalpies of formation and O-O and C-O bond strengths in polyoxides RO x R′ and RO x

Bond strengths in RO-OOR, ROO-OH, and ROO-OOR (R, R = H, Me, Et, and Bu) molecules, calculated by the semiempirical quantum-chemical methods, were used to determine the enthalpies of formation of polyoxides RO _x R (x = 3, 4) and related radicals and the bond strengths (D/kcal mol^–1) in these molecules:D(ROOO-OR) = 33.2±0.9,D(ROOO-OH) = 37.5±0.7,D(R-O _x R) = 76.0±1.2,D(H-000) = 58.6,D(R-000) = 42.8±0.8. A new value of Benson's polyoxide thermochemical increment, _f H°[O-(O)₂] = 11.1±1.0 kcal mol^–1, was suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2190–2193, September, 1996.     

Schiff base complexes of dioxouranium(VI), III. Commun.: Dioxouranium(VI) complexes of bibasic tetradentateSchiff bases

Bibasic tetradentateSchiff bases having the donor system OH–NX–NX–OH have been shown to form UO₂(NO₃)₂(SBH₂) type of derivatives [SBH₂ is the molecule of the bibasic tetradentateSchiff bases such as HOC₆H₄C(R) N(CH₂) _n NC(R)C₆H₄OH (where R=H or CH₃ andn=2 or 3) and HOC(R)CHC(CH₃)N(CH₂) _n NC(CH₃)CH C(R)OH (where R=CH₃ or C₆H₅ andn=2 or 3)]. The 11 stoichiometry of these complexes is shown by elemental analysis and conductometric titrations. The molar conductence values in nitrobenzene indicate the non-electrolytic behaviour and the magnetic susceptibility measurements by the Gouy method show these complexes to be diamagnetic.With 1 Figure     

Methyl and phenyl esters and thioesters of carboxylic acids as surrogate substrates for microassay of proteinase K esterase activity

The development of a microassay for proteinase K esterase activity with carboxylic acid esters is reported using novel substrates of the general formula R-C(O)-XR. Highest rates of hydrolysis have been obtained with the O-phenyl esters CH₃(CH₂)_{n = 1 – 2}-S-(CH₂)_{n = 1 – 2} C(O)-O-phenyl and their thioester analogs in studies where R, X and R have been varied. The phenol release has been measured with 4-aminoantipyrine and potassium ferricyanide to determine the rates of O-phenyl ester hydrolyses. Thioester hydrolyses have been monitored continuously with 5,5-dithio-bis (2-nitrobenzoic acid).     

Cationic β-diketonato molybdenum nitrosyl complexes: redox and structural properties

Summary -Diketones react with [Mo(NO){HB(dmpz)₃}I₂] [HB (dmpz)₃ = tris (3,5-dimethylpyrazolyl)borate] giving the cationic complexes [Mo(NO) {HB(dmpz)₃}{OC(R)CRC-(R)O}]⁺ (R = R = Me, R = H, Me or n-Bu; R = R = Ph, R = H; R = Me, R = n-Bu, R = H), isolated as triiodide salts. Electrochemical studies show that these complexes exhibit three electrode processes: two associated with oxidation of I _inf3 ^sup– and one with reduction of the metal-containing cation. Reduction of the cation where R = R = R = Me with cobaltocene afforded the neutral paramagnetic [Mo(NO) {HB(dmpz)₃} {OC(Me)CMeC(Me)O}], which was characterized by i.r. and e.p.r. spectroscopy. In contrast, 3-chloropentane-2, 4-dione reacts efficiently with [Mo(NO){HB(dmpz)₃}I₂] giving the known chloro-analogue, [Mo(NO)-{HB(dmpz)₃}Cl₂], and no -diketonate complex was detected. The X-ray crystal structure determination of [Mo(NO){HB(dmpz)₃} {OC(Me)CMeC(Me)O}]I₃ confirms that the cation is six-coordinate and shows that the 559-01 (diketonate) bonds are slightly longer than in comparable compounds, implying that the -diketonate ligand is not such a strong -donor as alkoxide groups.     

Investigation of conjugation in the Si-O-C-C-N system by nuclear magnetic resonance

The proton-magnetic-resonance spectra were investigated for 19 -aminoethoxysilanes in the R_4-nSi(OCH₂CH₂NR₂)_n and R_3-m(CH₂CH₂OR)_m series, where R=CH₃, C₂H₅, or C₆H₅; R=H, CH₃, C₂H₅, or Si(CH₃)₃; and the values of n and m are 1–4 and 1–3, respectively. In the Si-O-C-C-N system the effect of substituents at the nitrogen or silicon atoms is transmitted either by conjugation in the chain or, when the conjugation is broken, by an induction mechanism.     

Pyrimidines

It is shown that the reaction of benzalbisurea with 3-amino-5-hydroxy-1-R-pyrazoles gives 1-R-dipyrazolo[3,4-b:4,3-e]pyridine (R=CH₃) or a spiro(pyrazole-4,5-pyrimidine) derivative (R=C₆H₅). Similar reactions of benzalbisurea with 3-hydroxy-5-amino-1-methylpyrazole give 2-methyldipyrazole[3,4-b:4,3-e]pyridine or substituted tetrahydropyrazolo[3,4-d] pyrimidine. Only the corresponding dipyrazolo[3,4-b:4,3-e]pyridines are formed in the reaction of 1-methylhydroxyaminopyrazoles with methylenebisurea.See [1] for communication XXXIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 823–827, June, 1974.     

Zur Reaktion von Fluorsilanen mit lithiierten Aminen

The reaction of fluorosilanes with lithium salts of bulky amines like tetramethyl-piperidine and di-tert. butylamine leads to stable aminofluorosilanes of the type R-SiF₂-NRR [R=F, C(CH₃)₃, C₆H₅, C₆H₄N(CH₃)₂]. Lithium salts of silylamines react analogously: R₂Si(NR-SiF₂R)₂ (R=R= =CH₃, R=C₆H₅). An eight membered Si–N-ring is obtained in the reaction of a disubstituted silylaminofluorosilane with the dilithium salt of a silylamine. The mass-,¹H-, and¹⁹F-NMR spectra of the above mentioned compounds are reported.     

Metal chelates of ligands containing the ONS donor grouping,Part II. Metal chelates of schiff bases derived from β-diketones and α-N-Methyl-S-methyldithiocarbazate

Summary The Schiff bases RC(OH)=CHC(R)=NNMeC(S)SMe (R = Ph,p-MeC₆H₄, R = Me; R = R = Ph) have been prepared by condensation of -diketones with -N-methyl-S-methyldithiocarbazate. By the loss of a proton they act as singly negatively charged tridentate ligands with oxygen, nitrogen and sulphur donor atoms (ONS). Iron forms the high-spin complexes [Fe^III(ONS)₂][Fe^IIICl₄]. Copper(II), palladium(II), and platinum(II) yield the square-planar 1 : 1 complexes, M(ONS)CI (M = Cu, Pd, Pt) and Cu(ONS)NO₃. Cobalt(II) and nickel(II) form high-spin, six-coordinate 1 : 2 complexes, M(ONS)₂. For M = Ni and R = R = Ph, the complex is high-spin and octahedral, but when R = Ph orp-MeC₆ H₄ and R = Me, the complexes are diamagnetic and square-planar with nitrogen and sulphur (NS) coordinatio of the Schiff base, indicating that a change in the Rgroup can bring about a change in spin-state and stereochemistry of nickel.Part I: see ref. 1.     

Synthesis and reactivity of μ-η2-carbamato complexes of triosmium decacarbonyl

The synthesis of (-H)(-²-RRNCO₂)Os₃(CO)₁₀ (R=R=CH₃ 2a; R=R=CH₂CH₃,2b; R=CH₃, R=CH₂CH₃,2c) and their cyclic analogs (-H)(-²--CO₂)Os₃(CO)₁₀(n=42d,n=5,2e) from carbon dioxide, secondary amine, and Os₃(CO)₁₀(CH₃CN)₂ (1) are reported. A solid-state structure of2c reveals a bonding mode for the carbamato ligand very similar to that observed for related carboxylato complexes. Compound2c crystallizes in the orthorombic space group Pbca witha=9.136 (3),b=15.310 (4) andc=30.361 (5) Å;V=4247 ų,Z=8. Least-squares refinement of 2405 observed reflections gave a final agreement factor ofR=0.043 (R _w =0.043). The reactivity of the complexes2a–2e was examined. Compound2c or2b give good yields of the cluster derivatives (-H)(-X)Os₃(CO)₁₀ (X=Cl,3; X=OCH₃,4; X=N(CH₃)₂,7) when reacted with HX. Reaction of2a with P(CH₃)₃ at 68°C gives good yields of the otherwise difficult to obtain 1,1,2-(P(CH₃)₃)₃Os₃(CO)₉ (5). Evidence is presented that suggests that2a–2e form by oxidative addition of preformed carbamic acids to1.     

1-Aryl-6-azauracile, 4. Mitt.: Die Synthese des 1-Phenyl-5-[5′-methyl-1′,2′,4′-oxdiazolyl-(3′)]-6-azauracils und einiger seiner Derivate

Zusammenfassung Arylhydrazon-cyanacetylcarbamidsäureäthylester (I) wurde durch Einwirkung einer Na₂CO₃-Lösung auf 1-Aryl-5-cyan-6-azauracile (II)^1,2 cyclisiert. Nitrile (II) wurden durch Addition von Hydroxylamin in entsprechende Amidoxime (III) übergeführt, welche durch Kochen mit Acetanhydrid die zugehörigen 1-Aryl-5-[5-methyl-1,2,4-oxdiazolyl(3)]-6-azauracile (IV) lieferten.

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Aryl hydrazone-cyanoacetylcarbamic acid ethyl esters (I) have been cyclized in Na₂CO₃ soln. yielding 1-aryl-5-cyano-6-azauraciles (II)^1,2. Addition of NH₂OH to the nitriles (II) gave the corresponding amidoximes (III), which by refluxing with Ac₂O were converted to the corresponding 1-aryl-5-[5-methyl-1, 2, 4-oxdiazolyl(3)]-6-azauraciles (IV).

     

Bi- and polynuclear organometallic complexes of palladium(II) with 4,4′-bipyridine

Summary Binuclear organometallic palladium complexes of the general formulae Pd₂[-(N-N)]R₂L₄(ClO₄)₂ and Pd₂[-(N-N)]Cl₂R₂L₂ [R = C₆F₅ or C₆CI₅; L = group VB or VIB ligand; (N-N') = 4,4-bipyridine] have been prepared by reacting the ligand (N-N) with compounds of the type Pd₂(-CI)₂R₂L₂ or PdOClO₃RL₂. Furthermore, polynuclear [PdR₂(N-N)]_x (R = Cl, C₆F₅ or C₆Cl₅) type complexes have been obtained by reaction of the ligand (N-N) with PdR₂(tht)₂, whilst treatment of [Pd₂(-CI)₂(C₆F₅)₄](NBu₄)₂ with an excess of (N-N) leads to the polynuclearcis-[Pd(C₆F₅)z(N-N)]_x species. Evidence for the structure of these compounds is obtained from their i.r. spectra.     

Demetallation of coordination compounds of nickel with tetradentate ligands based on S-substituted isothiosemicarbazides

The passage of dry gaseous hydrogen chloride through chloroform solutions or acetone suspensions of S-substituted N¹,N⁴-di(salicylidene)isothiosemicarbazidates of nickel (Ni(LRR)) has led to a demetallization reaction with the liberation in the free state of S-substituted N¹,N⁴-di(salicylidene)isothiosemicarbazides with the general formula N₂LRR (where R is H and R is CH₃ (I); R is H and R is C₂H₅ (II); R is H and R is C₃H₇ (III); R is H and R is C₇H₇ (IV); and R is CH₃ and R is CH₃ (V)). The IR spectra of (I-IV) each showed bands characteristic for an aromatic ring and groups in the 1600–1500 cm^–1 region, with a band of the deformation vibrations of an OH group at 1300 cm^–1. The PMR spectra in CDCl₃ each had two singlets at 12.15-11.25 and 9.00-8.36 ppm which were assigned, respectively, to the protons of an OH group and those of a =CH group. A multiplet in the 7.70-6.83 ppm region belonged to the protons of benzene rings. In the region of lower fields there were the signals of the substituents R and R. In the mass spectra of (I-V), the peaks of the molecular ions, and also the characteristic fragments OH, R, SR, and HSR have been detected.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 21, No. 5, pp. 604–608, September–October, 1985.     

Isostructural triazenido complexes of first row transition metals. Part 1. Synthesis and properties of (η5-C5H5)(L)(RN3R) FeII,L = PPh3, P(OMe)3, P(OPh)3 or CO

Summary The complexes ( ⁵-C₅H₅)L(RN₃R)Fe, where L = PPh₃, P(OMe)₃, P(OPh)₃ or CO and R,R=p-MeC₆H₄ orp-ClC₆H₄, have been prepared by reaction of suitable iron halides with Ag(RN₃R). The mechanism of formation of the Fe(RN₃R) group is thought to involve, initially, an Fe-Ag bond. The bonding mode of the triazenido ligand is chelating in a six coordinate configuration. The spectroscopic results are discussed in relation to variations in the environment of the metal atom.     

Reaction of trialkylsilylalkanethiols with benzenesulfonyl chloride

Conclusions Depending on the ratio of the reactants and the reaction temperature, the reaction of benzenesulfonyl chloride with sodium trialkylsilylalkylthiolates R₃Si(CH₂)_nSNa (R=Me, Et; n=1–3) leads either to labile S-phenyl S-trialkylsilylalkyl thiosulfonates or to their mixture with S,S-bis(trialkylsilylalkyl) disulfides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 204–205, January, 1979.