Synthese und Eigenschaften der Furo- und Thieno-Analogen von PQQ-Triester

Synthesis and Characterization of the Furo and Thieno Analogues of the Triester of PQQ We report here the synthesis and properties of the furo and thieno analogues of 4,5-dihydro-4,5-dioxo-1H-pyrrolo[2,3-f]quinoline-2,7,9- tricarboxylic acid ( = PQQ), i.e. the furo- and thieno[2,3-f]quinoline-4,5-quinone (FQQ and TQQ, resp.) derivatives B and C , obtained as triesters. The triester of PQQ derivative A is much more stable than the triesters of B or C , and only the triester of A shows strong activity in nonenzymatic catalytic oxidations.     

Synthese und Eigenschaften der chelatbildenden heterocyclischen Polyamide. Polyamidbenzimidazol

Ohne Zusammenfassung     

Trimethylsilylverbindungen der Vb-Elemente. I Synthese und Eigenschaften von Trimethylsilylarsanen

Trimethylsilyl Derivatives of Vb-Elements. I. Syntheses and Properties of Trimethylsilylarsanes Chlorotrimethylsilane and ?Na₃As/K₃As”? prepared from a sodium potassium alloy and arsenic powder in dimethoxyethane form tris(trimethylsilyl)arsane 4 in 80 to 90percent; yield. 4 reacts with methyllithium in THF or dimethoxyethane to lithiumbis(trimethylsilyl)arsenide 5 , which crystallizes with two molecules THF – 5a – or one molecule dimethoxyethane – 5b – per formula unit. The latter adduct is dimeric in benzene. In the reaction of 5 with primary and secondary alkyl halides methyl- 1a , ethyl- 1b , isopropyl- 1c , benzyl- 1d , diphenylmethylbis(trimethylsilyl)arsane 1e and bis[bis(trimethylsilyl)arsano]methane 1f are formed. With tert. butyl chloride a β-elimination results in the formation of bis(trimethylsilyl)arsane; in the reaction with chlorodiphenylmethane and dibromoethane an alkali metal-halogen-exchange takes place yielding tetrakis(trimethylsilyl)-diarsane 6 . On heating bis[bis(trimethylsilyl)arsano]dimethylsilane 7 , synthesized from 5 and dichlorodimethylsilane, to 240°C for several days it decomposes to 4 and dodecamethyl-hexasila-tetra-arsa-adamantane 8 . Tert. butyl- 1g and phenylbis(trimethylsilyl)arsane 1h which cannot be obtained from 5 are prepared from primary arsanes via the corresponding dilithium derivatives.     

Synthese und Eigenschaften einiger Phenoxyarylsilane

Ohne Zusammenfassung     

Synthese und Eigenschaften einiger Iodtrisilane

The syntheses and properties of the iodotrisilanes (IH₂Si)₂SiH₂, (IH₂Si)₂SiHI, I₃SiSiI₂SiH₃, (I₃Si)₂SiH₂ and Si₃I₈ are reported. All trisilanes were synthesized from the appropriate phenyltrisilanes and hydrogen iodide, with the exception of I₅Si₃H₃, which was prepared by thermolysis of I₃SiSiH₃. The ²⁹ Si-chemical shifts and ²⁹Si²⁹Si-coupling constants are reported. ab]Die Synthesen und Eigenschaften der Iodtrisilane (IH₂Si)₂SiH₂, (IH₂Si)₂SiHI, I₃SiSiI₂SiH₃, (I₃Si)₂SiH₂ und Si₃I₈ werden beschrieben. Bis auf I₅Si₃H₃, das während der Thermolyse von I₃SiSiH₃, entstand, wurden alle Iodtrisilane aus den entsprechenden Phenyltrisilanen mit Iodwasserstoff hergestellt. Die ²⁹Si-Verschiebungen und ²⁹Si²⁹Si-Kopplungskonstanten werden mitgeteilt.     

Synthese und Eigenschaften linearer Phosphorylchlorphosphazene

Synthesis and Properties of Lineary Phosphorylchlorphosphazenes The phosphorylchlorphosphazenes, Cl₂(O)P—[N?PCl₂]_n—Cl, (n = 1, 2, 3) react like POCl₃ with hexamethyldisilazan forming silylamides, Cl₂(O)P—[N ? PCl₂]_n—NHSi(CH₃)₃, (n = 0, 1, 2, 3). From these are obtained the phosphorylchlorphosphazenes by reaction with PCl₅ containing one group —N ? PCl₂ more.     

Synthese und Eigenschaften von Spiro[1,3-benzodioxol-2,3′-pyrrolidin]

Spiro[1,3-benzodioxole-2,3′-pyrrolidine] was synthesized in several steps from ethyl 2-ethoxycarbonyl-1, 3-benzodioxole-2-acetate, prepared by condensation of pyrocatechol with either diethyl meso-dibromosuccinate, diethyl acetylenedicarboxylate or diethyl bromo maleate. The structural factors leading to the formation of the benzodioxole rather than the benzodioxan and some possible reaction mechanisms are discussed.     

Synthese und Eigenschaften von 6-Desoxy-6-halogen-Derivaten der L-Ascorbinsäure

Synthesis and Properties of 6-Deoxy-6-halogeno-Derivatives of L -Ascorbic Acid 6-Deoxy-6-chloro-, -6-bromo-, -6-iodo- and -6-fluoro derivatives of L -ascorbic acid have been synthesized and characterized. The physiological properties of the chloro derivative have been investigated. It shows a high antiscurvy activity. The chloro- and bromo-derivatives have been reduced to the corresponding deoxy compound, which is an interesting chiral intermediate for the preparation of rare ω-deoxy sugars.     

Synthese und spektroskopische Eigenschaften neuer komplexierter Triphosphane

Synthesis and Spectroscopy of new Triphosphine Complexes The reaction of PCl₃ with [HPPh₂W(CO)₅] in the presence of NEt₃ affords stepwise the diand triphosphine complexes [Cl₂PPPh₂W(CO)₅] and ClP[PPh₂W(CO)₅]. Triphosphine complexes of the type [{M′(CO)₅}(H)P{PPh₂M(CO)₅}] (M = M′ = Cr or Mo) are not formed from the reaction of HP[PPh₂M(CO)₅] with [M′(CO)₅thf]. However they were prepared by reaction of [M′(CO)₅PCl₃] with Li[PPh₂M(CO)₅]. The products were characterized by NMR, IR spectroscopy, and mass spectrometry.