Synthese und Zerfall von Azoinitiatoren,II

For further investigation of the relations between the structure and the decomposition of the azoesters of the typePhR ¹ R ²CN=CNR ² R ¹ Ph two supplement series (R ¹=CH₃, C₂H₅;R ²=substituted acetic acids) were synthesized. Especially information were obtained concerning the reasons for the low temperatures of decomposition of the azoesters of acetic acid. The azoesters of the substituted acetic acids follow a law of first order for the decomposition.     

Chelatbildende Enaminoketone II. Synthese von symmetrischen Liganden

Syntheses of Bis-enaminoketones are described, which are able to form square planar chelates with transition metals. Tetra- and multidentate ligands were prepared from anilinomethylene derivatives of 1,3-dicarbonyl compounds and various diamines. Lipophilic ligands were prepared with respect to potential use as carriers in liquid membrane permeation. Incorporation of the ligands into a polymer (via a spacer group) was performed by radical polymerization.

     

Synthese und Charakterisierung von Sulfinato-Nickel(II)-Komplexen

Synthesis and Characterization of Sulfinato-Nickel(II) Complexes Synthesis and properties of sulfinato-nickel(II) complexes of the type L₂Ni(Cl)SO₂R (L₂ = TMED, bipy, phen, DPPE, (PBu₃)₂; R = Ph, p-Tol, Me, NMe₂) are described. The compounds obtained are characterized by means of magnetic measurements, i.r. and reflectance spectra.     

Synthese einiger Glucuronid-Metaboliten von Phenacetin und Phenetidin,Teil II

The anomeric configuration of the main metabolite of phenacetin, p-acetamido-phenyl β-D -glucopyranosido-uronic acid, was established by configurative correlation with a cyclohexyl β-D -glucopyranosido-uronic acid derivative. Furthermore, some anomeric D -gluco-pyranoside conjugates of 2-ethoxy-5-acetamido-phenol were synthesized and characterized using NMR.-spectroscopy and ORD./CD.     

Synthese von Hydroxybenzylbenzimidazolen

Zusammenfassung Eine Reihe von Hydroxybenzylbenzimidazolen wurde durch Kondensation verschiedener aromatischer o-Diamine mit Brommandelsäuren unter Verwendung von 6n-HCl als Kondensationsmittel hergestellt. Für die Substituenten in der Benzolhälfte wurden die Stellungen 4(7)-, 5(6)-, 5,6- oder 4,6(5,7)- ge-wählt; der Phenylrest der Hydroxybenzylhälfte trägt ein Bromatom in der o- oder p-Stellung. Die Darstellung der o-Brom-mandelsäure wird beschrieben.

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A series of hydroxybenzylbenzimidazoles has been synthesized by condensing various aromatic o-diamines with bromomandelic acids using 6 N hydrochloric acid as condensing agent. o-Phenylene diamines to yield benzimidazoles substituted at positions 4(7)-, 5(6)- or 4,6(5,7)- were selected; the phenyl group of the hydroxybenzyl moiety carries a bromo substituent in the o- or p-position. The preparation of o-bromomandelic acid is described in some detail.

     

Synthese von Orellin

Synthesis of Orelline Orelline (1) , a metabolite of the toadstool Cortinarius Overllauns Fries with 2,2′-bipyridine structure, has been synthesized by the following method. The easily accessible 2-bromo-3-hydroxypyridine (3) was converted into the corresponding [2-(trimethylsilyl)ethoxy]methyl (SEM) ether 4 and coupled with Zn and NiCl₂/Ph₃P to form the bipyridine derivative 5 in 79% yield. Due to the chelating effect of the two SEM-ether groups in 5 , it was possible to from selectively the dilithium compound 6 by an exchange reaction with BuLi at ?50° in Et₂O. Reaction of 6 with electrophiles at ?20° afforded the 4- and 4,4′-substituted bipyridines 7–14 in excellent-to-reasonable yield. Oxidation of 6 with 2-(phenylsulfonyl)-3-phenyloxaziridin and with bis(trimethylsilyl)peroxide gave the 4,4′-diol 9 in 22 and 10% yield, respectively. Methanolysis of 9 directly afforded crystalline 1 in high yield, with properties identical with those of natural orelline. Formylation of 6 with N-formylmorpholine gave 45% of the dicarbaldehyde 13. Removal of the SEM groups in 13 by hydrolysis afforded the dihydroxydicarbaldehyde 15 that could be oxidized to 1 with alkaline H₂O₂. Attempts to oxidize 1 to orellanine (2) with 35% H₂O₂ according to a known procedure were unsuccessful (cf. Exper. Part). Compound 7 with two Me₃Si groups in 4,4′-position gave after methanolysis the fluorescence dye 16 with an appreciable Stokes shift in cyclohexane.     

Synthese von Mesitylaluminium-Verbindungen

Synthesis of Mesityl Aluminium Compounds Trimesityl aluminium, Al(C₉H₁₁)₃(thf), is easily prepared from aluminium chloride and solutions of Mg(C₉H₁₁)Br or Mg(C₉H₁₁)₂ in tetrahydrofuran. It loses tetrahydrofuran forming quite stable Al(C₉H₁₁)₃. Al(C₉H₁₁)Cl₂(thf) and Al(C₉H₁₁)Cl(thf) are obtained, too, from AlCl₃ and Al(C₉H₁₁)₃ or Mg(C₉H₁₁)₂, respectively.     

Synthese von Hexadecanolid

Ohne Zusammenfassung