Synthese und Strukturen neuer Ringverbindungen des Bismuts mit Tris(trimethylsilyl)silyl und ‐stannylresten – [(Me3Si)3Si]4Bi4 und [(Me3Si)3Sn]6Bi8

Synthesis and Structures of Novel Ring Compounds of Bismuth with Tris(trimethylsilyl)silyl and ‐stannyl Substituents – [(Me₃Si)₃Si]₄Bi₄ and [(Me₃Si)₃Sn]₆Bi₈ A bicyclo[3.3.0]octane‐like core consisting of eight bismuth atoms is found in the novel octabismuthane Bi₈[Sn(SiMe₃)₃]₆. It is prepared like Bi₄[Si(SiMe₃)₃]₄ by reduction of BiBr₃ with Li(thf)₃E(SiMe₃)₃ (E = Si, Sn) together with (Me₃Si)₆E₂. Both bismuth ring compounds have been characterized by single crystal X‐ray crystallography.     

Synthesen und Kristallstrukturen von [(t-Bu4Sb4)Fe(CO)4], [(t-Bu4Sb4)Mo(CO)5] und [(t-Bu3Sb4)Mo(η5-C5Me5)(CO)3]

Syntheses and Crystal Structures of [( t -Bu₄Sb₄)Fe(CO)₄], [( t -Bu₄Sb₄)Mo(CO)₅], and [( t -Bu₃Sb₄)Mo(η⁵-C₅Me₅)(CO)₃] t-Bu₄Sb₄ reacts with Fe₂(CO)₉ to form [(t-Bu₄Sb₄)Fe(CO)₄] ( 1 ). [(t-Bu₄Sb₄)Mo(CO)₅] ( 2 ) is formed from (thf)Mo(CO)₅ and t-Bu₄Sb₄. [(t-Bu₃Sb₄)Mo(η⁵-C₅Me₅)(CO)₃] ( 3 ) is a product of the reaction of t-Bu₄Sb₄ with [(η⁵-C₅Me₅)Mo(CO)₃]₂. The crystal structures of 1–3 are reported.     

A practical synthesis of 4-[(4-methylpiperazin-1-yl)methyl]benzoic acid—the key precursor toward imatinib

A simple and efficient in situ synthesis of 4-[(4-methylpiperazin-1-yl)methyl]benzoic acid through direct reductive alkylation of 1-methylpiperazine in the presence of triacetoxy sodium borohydride in 95-99% yields is elaborated. The process is easy to scale-up for the large-scale synthesis of 4-[(4-methylpiperazin-1-yl)methyl]benzoic acid as the key synthetic intermediate of imatinib. This method was used for the synthesis of benzyl derivatives of heterocyclic amines in 87-90% yields.     

Alkyne Addition and Insertion Reactions of [(Me3Si)3Si]2Ge⋅PMe3

Silylated germylene–PMe₃ adducts exchange their phosphane moiety smoothly for an N‐heterocyclic carbene or isocyanide species to form their respective base adducts. Reaction of the silylated germylene–PMe₃ adducts with monosubstituted alkynes produce germylene adducts with the alkyne inserted into a Ge?Si bond. A computational study of this process provides evidence for the initial formation of a germirene, which rearranges to a vinylgermylene species. The thermodynamic driving force for this reaction is provided by subsequent adduct formation with PMe₃. Reaction of the PMe₃ adduct of bis[(trimethylsilyl)silyl]germylene with disubstituted alkynes leads to the formation of stable germirenes, which can be isomerized further to silagermetes.     

The First Orthotelluric Acid Polysilylesters: Synthesis and Crystal Structure of [(Me3SiO)8Te2O2] and [(Me4Si2O2)3Te]

The compounds [(Me₃SiO)₈Te₂O₂] ( 1 ) and [(Me₄Si₂O₂)₃Te] ( 2 ) have been prepared in good yields through Bronsted acid‐base reaction of Te(OH)₆ with Me₃SiNEt₂ and Me₄Si₂(NEt₂)₂, respectively. They have been characterised by multinuclear NMR spectroscopy and single crystal X‐ray diffraction analyses. The formation of dinuclear 1 is the result of fast intermolecular condensation of two partially silylated orthotelluric acid units during the esterification process. Its structure consists of two edge‐fused TeO₆‐octahedra, bearing a four‐membered Te₂O₂ ring as central motif. In contrast, the main structural feature of chiral 2 is a TeO₆ octahedron which is fully silylated by three bidentate 1,1,2,2‐tetramethyldisilanediyl units, resulting in a racemic mixture. The metastability of 2 is remarkable since the Te(+ 6) center usually acts as a strong oxidation reagent toward the Si–Si bond in disilanes. 1 and 2 represent potential starting compounds for molecular Te_xO_y aggregates as hybrid components for new glasses by sol‐gel procedure.     

Reaktionen von R4Sb2 (R = Me,Et) mit (Me3SiCH2)3M (M = Ga,In) und Kristallstrukturen von [(Me3SiCH2)2InSbMe2]3 und [(Me3SiCH2)2GaOSbEt2]2

Reactions of R₄Sb₂ (R = Me, Et) with (Me₃SiCH₂)₃M (M = Ga, In) and Crystal Structures of [(Me₃SiCH₂)₂InSbMe₂]₃ and [(Me₃SiCH₂)₂GaOSbEt₂]₂ The reaction of (Me₃SiCH₂)₃In with Me₂SbSbMe₂ gives [(Me₃SiCH₂)₂InSbMe₂]₃ ( 1 ) and Me₃SiCH₂SbMe₂. [(Me₃SiCH₂)₂GaOSbEt₂]₂ ( 2 ) is formed by the reaction of (Me₃SiCH₂)₃Ga with Et₂SbSbEt₂ and oxygen. The syntheses and the crystal structures of 1 and 2 are reported.     

Alkyl complexes of strontium and barium: synthesis and structural characterization of [(Me3Si)2(MeOMe2Si)C]2Sr(THF) and [(Me3Si)2(MeOMe2Si)C]2Ba(MeOCH2CH2OMe)

Metathesis between either SrI2 or BaI2 and 2 equiv of {(Me3Si)2(MeOMe2Si)C}K in THF yields the novel heavier alkali metal dialkyls {(Me3Si)2(MeOMe2Si)C}2M(L) [M(L) = Sr(THF) (2), Ba(DME) (3) (DME = 1,2-dimethoxyethane)] after recrystallization.     

Bis(bis(trimethylsilyl)phosphino)silan [(Me3Si)2P]2SiH2 und 1,2-Bis(bis(trimethylsilyl)phosphino)disilan [(Me3Si)2PSiH2]2

The compounds H₂Si[P(SiMe₃)₂]₂ and [H₂SiP(SiMe₃)₂]₂ were prepared and characterized by ²⁹Si NMR, ³¹P NMR, IR and Raman spectroscopy. After thermolysis of these compounds no cyclic silylphosphanes could be detected in the reaction mixture,although this did contain P(SiMe₃)₃.     

[μ‐(Me3SiCH2Sb)5–Sb1,Sb3–{W(CO)5}2] und [{(Me3Si)2CHSb}3Fe(CO)4] – zwei cyclische Komplexe mit Antimon‐Liganden

Syntheses and Crystal Structures of [μ‐(Me₃SiCH₂Sb)₅–Sb¹,Sb³–{W(CO)₅}₂] and [{(Me₃Si)₂CHSb}₃Fe(CO)₄] – Two Cyclic Complexes with Antimony Ligands cyclo‐(Me₃SiCH₂Sb)₅ reacts with [(THF)W(CO)₅] (THF = tetrahydrofuran) to form cyclo‐[μ‐(Me₃SiCH₂Sb)₅–Sb¹,Sb³–{W(CO)₅}₂] ( 1 ). The heterocycle cyclo‐ [{(Me₃Si)₂CHSb}₃Fe(CO)₄] ( 2 ) is formed by an insertion reaction of cyclo‐[(Me₃Si)₂CHSb]₃ and [Fe₂(CO)₉]. The crystal structures of 1 and 2 are reported.     

[Me4N]2[(WOS3Ag)2]: a novel quasi-one-dimensional compound

Orange–yellow plate-like crystals of a new polymeric complex [Me₄N]₂[(WOS₃Ag)₂] were obtained at room temperature from the reaction of a suspension of [Me₄N]₂[WOS₃] in MeCN with solid AgCN. The new compound is obviously formed by cyanide elimination of primary [WOS₃(AgCN)]²⁻. It is monoclinic space group P2₁/c with unit cell parameters a=20.44(2) Å, b=9.655(6) Å, c=11.913(5) Å, β=99.06(2)°, Z=4. The crystal structure was determined from single crystal diffractometer data (Mo-Kα radiation) and refined to R=0.070 (2979 reflections, 199 variables). The structure is characterized by infinite anionic chains, ${}_{\mathrm{\infty }}{}^{\mathrm{<mspace\; xmlns="true"\; sp="0.3"\; width="2px"\; linebreak="nobreak"\; is="true"></mspace><mtext>1</mtext>}}$[(WOS₃Ag)₂]²⁻. The infrared spectrum of the complex (KBr powder) shows the terminal ν(WO) as strong absorption bands found at 913 and 905 cm⁻¹. The bridging ν(WS) shows bands at 438 (vs) and 434 (sh) cm⁻¹. The anionic mass spectrum shows a peak at m/z 404 for [WOS₃Ag]⁻. In addition, the primary formation of the potential monomeric precursor [WOS₃(AgCN)]²⁻ could be established in the filtrate by mass spectroscopy.     

The first synthesis of 3-nitro-4-[(s-tetrazin-3-yl)amino]furazans

Oxidation of 3-amino-4-[(s-tetrazin-3-yl)amino]furazans with peroxy acids or 30% H2O2/Na2WO4/H2SO4 system results in transformation of the amino group into the nitro one and is accompanied by formation of N-oxides at tetrazine moiety.     

Crystal and molecular structure of [i-Pr2Si]4 and [(Me3SICH2)2Si]4 and some structural properties of cyclopolysilanes, [R1R2Si]n (n = 3-6)

The crystal structures of octaisopropylcyclotetrasilane [i-Pr₂Si]₄ (1) and octakis(trimethylsilylmethyl)cyclotetrasilane [(Me₃SiCH₂)₂Si]₄ (2) have been determined by means of X-ray diffraction analysis. Various crystallographic and structural data for the two compounds were recorded. The Si₄ rings of the compounds are nonplanar with quite large dihedral angles of 37.1° in (1) and 36.6° in (2), being comparable to that (36.8)° for [t-BuMeSi]₄ reported previously and other characteristic features in the structures of (1) and (2) were described. Some structural properties of the cyclic catenation systems, [R¹R²Si]_n (n = 3–6), including (1) and (2) were also discussed from a comparative viewpoint with respect to the ring shape and the relationship between ring size and Si-Si bond length.     

[(CH3)3Si]14Si7O21 – ein neuer cyclischer Kieselsäuretrimethylsilylester

[(CH₃)₃Si]₁₄Si₇O₂₁ — A New Cyclic Silicic Acid Trimethylsilyl Ester A new silicic acid trimethylsilyl ester was obtained by trimethylsilylation of barium chloride silicate 2 BaO · 3 BaCl₂ · 2 SiO₂. The ester was investigated by capillary gas chromatography, mass spectrometry, ²⁹Si n.m.r. spectroscopy, and thinlayer chromatography and was found to be a cycloheptasilicic acid trimethylsilyl ester (tetradecakis-trimethylsiloxicyclohepta siloxane) of the formula [(CH₃)₃Si]₁₄Si₇O₂₁. The application of the new compound as a standard substance is discussed.     

Synthesis and structures of heterocyclic azidogallanes [(CH3)ClGaN3]4 and [(CH3)BrGaN3]3 en route to [(CH3)HGaN3]x: an inorganic precursor to GaN

The synthesis of [(CH3)ClGaN3]4 (1) with a heterocyclic cyclooctane-like structure and [(CH3)BrGaN3]3 (2) with a trimeric structure has been demonstrated. X-ray structural determinations reveal that 1 and 2 consist of Ga4N4 eight-membered rings and Ga3N3 six-membered rings, respectively, in which the Ga atoms are bridged by the alpha nitrogens of the azide groups. [(CH3)ClGaN3]4 crystallizes in the tetragonal space group P42(1)c with a = 11.017(4) A, c = 8.699(7) A, and Z = 8. [(CH3)BrGaN3]3 crystallizes in the triclinic space group P1 with a = 8.1080(10) A, b = 9.9390(13) A, c = 10.4439(13) A, alpha = 86.069(3) degrees, beta = 86.771(3) degrees, gamma = 80.829(2) degrees, and Z = 6. The reaction of 1 and 2 with LiGaH4 yields [(CH3)HGaN3]x, which is a new low-temperature source of GaN.     

Untersuchungen zur Reaktionsfähigkeit der höheren Silylphosphane (me3Si)4P2, [(me3Si)2P]2PH, [(me3Si)2P]2P–Sime3 und (me3Si)3P7

Investigations Concerning the Reactivity of the Higher Silylphosphanes (me₃Si)₄P₂, [(me₃Si)₂P]₂PH, [(me₃Si)₂P]₂P—Sime₃, and (me₃Si)₃P₇ The reaction of (me₃Si)₂P? P(Sime₃)₂ 1 in ether solutions (THF, monoglyme) with t-buLi (me ? CH₃; t-bu ? (CH₃)₃C) yields (me₃Si)₃P, (me₃Si)₂PLi and Li₃P₇ via (me₃Si)₂P? P(Li) (Sime₃) 4 . Already at ?40° (me₃Si)₃P₂Li 4 decomposes yielding (me₃Si)₂PLi, Li₃P₇ and (me₃Si)₃P. The metallation of (me₃Si)₃P₂H with t-buLi leads to the same results. t-buLi with [(me₃Si)₂P]₂PH 2 in pentane forms [(me₃Si)₂P]₂PLi, which reacts on with meCl or me₃SiCl to [(me₃Si)₂P]₂Pme or [(me₃Si)₂P]₂PSime₃, resp. On addition of monoglyme to a suspension of [(me₃Si)₂P]₂PLi in pentane, or by treating [(me₃Si)₂P]₂PH in ethers with t-buLi (me₃Si)₂PLi, Li₃P₇, (me₃Si)₃P, are formed. The same compounds are generated by reacting [(me₃Si)₂P]₂P—Sime₃ in ethers with t-buLi. The metallation of (me₃Si)₃P₇ in ethers with t-buLi yields (me₃Si)₂PLi, (me₃Si)₃P, (t-bu)₃P₄?(Sime₃), Li₃P₇ and a red solid. The formation of (me₃Si)₂P₇Li is the first step of this reaction.