Kettenverlängerung am P2(SiMe3)4 durch Reaktion mit LiBu

Extension of the Chain Length of P₂(SiMe₃)₄ by Reaction with LiBu The first steps of the reaction of P₂(SiMe₃)₄ 1 with LiBu in THF, which finally yields Li₃P₇ among other P-rich phosphides while P(SiMe₃)₃ and LiP(SiMe₃)₂ are simultaneously split off, were investigated by means of ³¹P-NMR spectroscopy. At ?20°C first of all one Si? P bond is cleaved generating Li(Me₃Si)P? P(SiMe₃)₂ 2 as well as BuSiMe₃. Subsequently 2 forms Li(Me₃Si)P? P(SiMe₃)? P(SiMe₃)₂ 5 and LiP(SiMe₃)₂ 4 in equimolar ratios. This clearly demonstrates that both compounds are generated in one single reaction step. This behaviour is caused by the different basicity of the respective P-atoms in 2 , which necessarily results in a multicentered mechanism.     

Kondensations- und Transiminierungsreaktionen von N-Lithiosulfinsäureimidamiden mit Chlorsilanen und -phosphanen

Condensation and Transimination Reactions of N-Lithiosulfinicacidimide Amides with Chlorosilanes and -phosphanes The reactions of N-Lithiomethanesulfinicacidimide amides Me? S(NR)NRLi ( 1 ) (R ? t-Bu or Me₃Si) with chlorosilanes and -phosphanes were studied. Metathetical reactions of 1 with chlorotrimethylsilane lead to the formation of sulfinicacidimideamidosilanes Me? S(NR) NRSiMe₃ ( 2 ). Instead of forming the corresponding phosphane derivatives, the reactions of 1 with chlorodiphenylphosphane proceed via S→P-“redox-transimination” yielding N(iminophosphoranyl)-sulfenicacidamides Me? S? NR? P(?NR)Ph₂ ( 3 ).     

Darstellung und Untersuchung von Phosphinkomplexen mit Aluminiumtrichlorid und Aluminiumtriäthyl

Synthesis and Investigation of Complexes of Phosphines with AlCl₃ and AlEt₃ (t.-Bu)₃P and (Me₃Si)₃P form similar adducts with AlCl₃ and AlEt₃ (t.-Bu = ? C(CH₃), Me = ? CH₃, Et = ? C₂H₅). Analogous compounds are formed by reaction of (t.-Bu)₂PSiMe₃ with AlCl₃ and AlEt₃, and of (Me₃Ge)₃P and (Me₃Sn)₃ with AlEt₃. The i.r., Raman, ¹H-n.m.r. and ³¹P-n.m.r. spectroscopic data are reported and discussed.     

Neuartige Cycloadditionsreaktionen von 2- und 4-Vinylpyridin mit N-Alkyl-maleinimiden

4-Vinylpyridine ( 1a ) combines with 3 moles of dienophilic N-alkyl-maleinimides ( 2 ) in the presence of polymerization inhibitors. The first step of the reaction probably consists of 1:1-addition with participation of an aromatic double bond, comparable to the analogous behavior of styrene and its derivatives under similar conditions. The unstable intermediates 3 , like other Schiff bases (imines), add 2 further moles of the N-alkyl-maleinimides forming the spiro compounds 4 . These are split in an acidic medium into the N-alkyl-5,6,7,8-tetrahydroisoquinoline-7,8-dicarboximides ( 5 ), and N,N′-dialkyl-2-butene-1,2,3,4-tetracarboxylic 1,2,:3,4-diimides ( 6 ). LiAlH₄ reduction of these two types of compounds leads to N-alkyl-1 H-(3,4-d)-pyrrolo-2,3,3a,4,5,9b-hexahydroisoquinolines ( 7 ) and to N,N′dialkyl-3,3′-bipyrrolidyls ( 8A ) and their dehydro-products 8B , respectively. From the reaction of 2-vinylpyridine ( 1b ) with N-alkyl-maleinimides ( 2 ) the 1:2-addition products 9 can be isolated in the presence of polymerization inhibitors, which are derivatives of N-alkyl-5,6,7,8-tetrahydroquinoline-5,6-dicarboximides ( 9 ). This again corresponds to the reaction type of cycloadditions with styrene. Furthermore 1:3 adducts are formed which according to ¹H- and ¹³C-NMR.-data most likely have the structure 10 , representing a new type of cycloaddition involving the pyridine nitrogen.     

Reaktionen von Trihalogendithiatriazinen und Trifluortriazin mit Halogen-Lewis-Säuren

Reactions of Trihalodithiatriazines and Trifluorotriazine with Halogen-Lewis-Acids . From the reaction of (XCN)(XSN)₂ and MX₅ (X = Cl, M = Sb; X = F, M = As) the corresponding salts [(XCN)(XSN)(SN)]⁺MX₆^? ( 2, 4 ) are obtained. (FCN)₃ adds AsF₅ to the nitrogen-bonded adduct (FCN)₃ · AsF₅ ( 6 ). The X-ray-structure of 6 is reported.     

Photochemische reaktionen von äthern mit 4-methylcinnolin und chinoxalinen

1. 4-Methylcinnoline on irradiation in ethers produces the photoproducts 2–6 by a 1.4 addition of the ethers. 2. Quinoxaline reacts with ethers to produce the quinoxalines 8, 12 and 13 by what appears superficially to be a substitution process. Reaction of 2,3-dimethylquinoxaline with tetrahydrofuran gives as the main product 16 by 1.2 addition, and 2-(t-butyl)-quinoxaline gives the dihydroquinoxaline derivatives 17a, b . Because of the known easy autoxidation of 1,2-dihydroquinoxaline we believe that the intermediate in the photolytic reaction of quinoxaline, yielding 8, 12 and 13 , is also the 1.2 addition product. 3. The mass-spectrometric behaviour of the cinnoline and quinoxaline derivatives has been discussed.     

Bortrifluorid-katalysierte Umsetzungen von 3-Amino-2H-azirinen mit Aminosäure-estern und Aminen

Boron-Trifluoride-Catalyzed Reactions of 3-Amino-2H-azirines with Amino-acid Esters and Amines After activation by protonation or complexation with BF₃, 3-amino-2H-azirines 1 react with the amino group of α-amino-acid esters 3 to give 3,6-dihydro-5-aminopyrazin-2(1H)-ones 4 by ring enlargement (Scheme 2, Table 1). The configuration of 3 is retained in the products 4 . With unsymmetrically substituted 1 (R¹ ≠ R²), two diastereoisomers of 4 (cis and trans) are formed in a ratio of 1:1 to 2:1. With β-amino-acid esters 5 and 7 , only openchain α-amino-imidamides 6 and 8 , respectively, are formed, but none of the seven-membered heterocycle (Scheme 3). Primary amines also react with BF₃-complexed 1 to yield α-amino-imidamides of type 9 (Scheme 4, Table 2). Compound 9b is characterized chemically by its transformation into crystalline derivatives 10 and 12 with 4-nitrobenzoyl chloride and phenyl isothiocyanate, respectively (Scheme 5). The structure of 12 is established by X-ray crystallography. Mechanisms for the reaction of activated 1 with amino groups are proposed in Schemes 6 and 7.     

Zur Mitfällung von FeIII und CuII mit Bismutphosphat und Calciumfluorid

About the Coprecipitation of Fe^III and Cu^II with Bismuth Phosphate and Calcium Fluoride The mechanism of Fe^III and Cu^II coprecipitation with BiPO₄ and CaF₂ as carriers from ammonium phosphate and ammonium fluoride solutions was investigated. Using the radioactive tracers ⁵⁹Fe and ⁶⁴Cu and by means of EPR measurements surface adsorption was shown to be main reason causing coprecipitation. Trace metals distribution was possible to be described by means of Henry and Freundlich isotherms. Fe^III and Cu^II are coprecipitated with BiPO₄ as counterions to excess phosphate species at the surface. Differences in the behaviour between these metals are of quantitative nature. Cu^II is coprecipitated with CaF₂ as a counterion to excess F^?, whereas Fe^III adsorption takes place as FeF₆^3? in competition with matrix fluoride.     

Beiträge zum thermischen Verhalten von Sulfaten. VIII. Zum chemischen Transport von FeSO4 mit NH4Cl und von von Fe2(SO4)3 mit Cl2 oder NH4Cl. Experimente und Modellrechnungen

Contributions on the Thermal Behaviour of Sulfates. VIII. The Chemical Vapour Transport of FeSO₄ with NH₄Cl and Fe₂(SO₄)₃ with Cl₂ or NH₄Cl. Experiments and Calculations Well shaped crystals of FeSO₄ and Fe₂(SO₄)₃ can be grown by CVT (T₁? 650°C). We investigated the dependence of the transport rate on the concentration of the transport agent (Fe₂(SO₄)₃/Cl₂ and Fe₂(SO₄)₃/NH₄Cl) as well as on the temperature (FeSO₄/NH₄Cl and Fe₂(SO₄)₃/Cl₂). Using Δ_fH(FeSO₄) = ?220 kcal/ mol, C^p(T) = 30.1 + 9.9 · 10^?3 ×T and Δ_fH(Fe₂(SO₄)₃) = ?615.4 kcal/mol a satisfying agreement between thermodynamical calculations and experimental results can be reached     

Beiträge zur Chemie der Oxidhalogenide von Molybdän und Wolfram. IV. Der Transport von MoO2 mit J2 und die Existenz von MoO2J2

The possibility to transport MoO₂ with J₂ in a temperature gradient T₂/T₁ suggests the existence of MoO₂J₂. Starting from the reaction MoO₂ + J₂ ? MoO₂J₂ in the consideration of the function of temperature for the rates of chemical transport, the values ΔH^O_R ? 28.8 (±2) kcal/mole and ΔS^O_R ? 9.0 (±2) cl are deduced. From this the values ΔH^O(MoO₂J₂, g, 298) ? ?99.5 (±3.5) kcal/mole and S^O(MoO₂J₂, g, 298) ? 86 (±3) cl are derived. The comparison of the thermodynamic data for MoO₂X₂ and WO₂X₂ (X = Cl, Br, J) leads to the conclusion, that the existence of MoO₂J₂ in the vapour phase is very probable indeed.     

Der chemische Transport von FeP2 und FeP4 mit lod

Chemical Transport of FeP₂ and FeP₄ with Iodine Experiments on the chemical transport of FeP₂ and FeP₄ with iodine are discussed, considering the gaseous molecules I₁, I₂, FeI₂, Fe₂I₄, FeI₃, Fe₂I₆, PI₃, P₂I₄, P₄, P₂, and P. Thermodynamic calculations give δH°(298) = 56.322 kcal and ΔS°(298) = 39.5 cal/K for the reaction FeP_2,f + I₂ = FeI₂ + 0.5 P₄ and δG°(923) = 35.8 kcal for the reaction FeP_4,f + I₂ = FeI₂ + P₄.     

Darstellung und Charakterisierung von Chloroligosilanen mit mittelständigem Wasserstoff

Preparation and Characterization of Chloroligosilanes with Internal Hydrogen . Unbranched chlorinated tri-, tetra-, and pentasilanes with internal hydrogen substituent are synthesized from the corresponding phenylsilanes by cleaving off the phenyl groups with HCl/AlCl₃ and characterized by spectroscopy. Coupling of phenylsilylpotassium compounds, isolated from their mercury analogs, was used to prepare the phenylsilanes.     

Umsetzung von 2-Azidoalkoholen mit Trialkylphosphiten Bildung von Aziridinen und Amidophosphorsäureesten via Imidophosphorsäureester und 1,3,2λ5-Oxazaphospholidine

Reaction of 2-Azidoalcohols with Trialkylphosphites. Formation of Aziridines and Amidophosphates via Imidophosphates and 1,3,2λ⁵-Oxazaphospholidines The 2-azidoalcohols 1 and 2 react with trialkyl phosphites to trialkyl (2-hydroxy-alkyl)imidophosphates 10, 14 , and 15 respectively, whereas the 2-azidoalcohols 3-7 yield the 2,2,2-trialkoxy-1,3,2λ⁵-oxazaphospholidines 16–22 under the same reaction conditions (Scheme 2). The dialkyl (2-hydroxyalkyl)amidophosphates 23, 25 , and 27–34 are obtained by the reaction of 10 , and 14–22 with water (Scheme 3 and 4). By reaction with alcohols, however, both the imidophosphates 10, 14 and 15 and the 1,3,2λ⁵-oxazaphospholidines 16–22 are transformed to aziridines 24, 26 , and 35–38 (Scheme 5). The reactions of the imidophosphates seem to proceed via 1,3,2λ⁵-oxazaphospholidines.