Cyclische Kieselsäurederivate

Cyclic Silicic Acid Derivatives By reaction of SiCl₄ with oxygen at elevated temperatures a number of chlorsiloxanes consisting of more or less fused rings can be prepared of which those components of low molecular weight can be separated by combining distillation and crystallization. Methyl and ethyl esters of silicic acids are obtained by reaction with methyl or ethyl nitrite, resp. The compounds are characterized by silicon n.m.r. and mass spectroscopy.     

Phosphono- und Phosphinoameisensäurederivate via Alkoxycarbonylphosphon- und -phosphinsäuretrimethylsilylester

Phosphono-Phosphinoformic Acid Derivatives via Alkoxycarbonylphosphono and Phosphino Acid Trimethylsilylesters The sodium salts, the chlorides and amides of the phosphono- and phosphinoformic acid esters are easily prepared under various conditions from the corresponding alkoxycarbonyl-P-trimethylsilylesters. The alkoxycarbonyl group of the synthesized compounds it not Stable in acidic solution because of an autocatalytic decarboxylation. Under these conditions the chlorides and amides are hydrolyzed too. The Structure of the compounds prepared are discussed by means of their n.m.r. data.     

Neue Komplexbildner auf der Basis stickstoffhaltiger Oxalsäurederivate

Nitrogen Derivates of Oxalic Acid as New Complexing Agents Heterocycles with a exocylic 1,4-diaza-1, 3-diene structure 5a–d have σ-bonding and π-backbonding properties similar to the diazadienes (DAD) 1 . The investigations of the molybdenum complexes 11 and 12 of the ligands 5 show a dominant σ-interaction and only a small π-backbonding, comparable with the compound (CO)₄Mo(iPYC) 14 , a complex of pyridinecarbaldehyde isopropylimine (iPYC). The oxalamidine (TPOA) 4 (precursor of the heterocycles 5a–d ) are present in a s-trans (E/E)-form with two stable intra-molecular hydrogen bridges. 4 reacts with ferrous and cobaltous chloride to the polymer coordination compounds 8 and 9 . According to the diazadiene 1 oxalamadine 4 substitutes two carbonyls in Mo(CO)₆ by formation of (CO)₄Mo(TPOA) 10 . The coordinated ligand 4 shows in the complex 10 a s-cis(E/E)-form with respect to the free ligand and no H-bridges were observed. The crystal structures of TPOA 4 and (CO)₄Mo(TPOA) 10 were determined. Cyclisation reactions on the coordinated oxalamidine are possible.     

Über Triphosphorsäurederivate des Cyanamids und des Harnstoffs

Triphosphoric Acid Derivatives of Cyanamide and Urea Cyanamidotriphosphate, P₃O₉NCN^5? ( I ), is obtained by ring opening reaction of the cyclotriphosphate ion, P₃O₉^3?, by cyanamide in alkaline solution. As a pseudochalcogeno-substituted triphosphate, I has similar properties like the triphosphate, P₃O₁₀^5? (Ca²⁺ sequestering; behaviour on acidimetric titration; X-ray powder diffraction of the sodium salt hydrates). In acidic solution I decomposes forming ureidotriphosphate with the anion P₃O₉NHCONH₂^4? ( II ) which cannot be directly obtained from cyclotriphosphate and urea. II is characterized by its chemical analysis, by paper chromatography, by its behaviour in acidic solution and by its IR and ³¹P-NMR spectra. Solid salts of I and II are prepared and the data of their Guinier diagrams are communicated.     

Synthetische Juvenilhormone 4. Mitteilung. p-Substituierte 5-Phenyl-penten(1)-carbonsäurederivate

The synthesis of p-substituted 2-methyl-5-phenyl-penten(1)-carboxylic acid derivatives is described: the formed Grignard compounds react with ethylene-oxide to the corresponding alcohols which are transformed by following reactions to the above mentioned compounds.     

Reaktive Radikalionen

Im Heigenbrücken trafen sich anlässlich des Workshops „Radical Ion Reactivity in Biology, Chemistry and Technology”︁ vom 16.‐21. Juni 60 Wissenschaftler und Nachwuchswissenschaftler aus aller Welt zum Austausch. Dieser Workshop, von Michael Schmittel (Siegen) organisiert und von der Volkswagenstiftung gefördert, umfasste alle aktuellen Forschungsrichtungen der Radikailonenchemie.     

Synthetische Juvenilhormone 3. Mitteilung. p-Substituierte 4-Phenyl-buten(1)-carbonsäurederivate

The syntheses of p-substituted 2-methyl-4-phenylbuten(1)-carboxylic acid derivatives are described, using Blanc's chloromethylation reaction, the Friedel-Crafts alkylation of unsaturated ketones or the Meerwein arylation; the formed intermediates react in subsequent steps to the title compounds.     

Synthetische Juvenilhormone 1. Mitteilung. p-Substituierte β-Methyl-Zimtsäurederivate

In the first communication the synthetic methods are described for preparing aromatic analogues of juvenile hormone like activity. The para-substituted 2-methyl-cinnamic acid derivatives are formed by a Friedel-Crafts acylation of a phenol, followed by the Wadsworth-Emmons (Wittig-Horner)-Reaction with the corresponding phosphonates. More than 120 compounds are listed.