This review deals of addition reactions of the Ge-H function of halogenhydroorganogermanes R(x)Ge-(Hal)(v)H(z) (R = organic ligand, Hal = F, Cl, Br, I; x + y + z = 4) to unsaturated compounds.
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The Azaile derivative 16 was obtained in a 7-step procedure starting from Boc-ACHP-OMe (4), generating the C-terminal aza-amino acid residue using the carbazic acid-activated ester technique followed by chain elongation. Compound 16 could be shown to be a specific inhibitor of human renin. In computer graphic investigations comparing the conformations of 16 and the corresponding "purely peptidic" compound 3 marked deviations could be demonstrated.
Lignin as the second abundant macromolecular natural compound on earth is in structural respect no uniform material. Depending on genetic origin, structural features, and the way of isolation or syntheses there exist several possibilities of classification for lignin. Great importance has the arrangement of lignin preparations by their isolation and syntheses methodes for which a review is given. Acidic-, hydrosolv-, enzymic-, and organosolv lignin as well as synthetic model compounds are particularly considered.
By reaction of dimethyldichlorosilane and paramethylstyrene with sodium as reductive agent the synthesis of a series of different composed poly(dimethylsilane-co-paramethylstyrenes) PMS-pMSt was afforded. Molar ratios of monomers used were (CH3)2SiCl2:p-CH3C6H4CHCH2 = 19; 9; 5; 4; 2; 1; 0,5; 0,25 PMS-pMSt 1-8 respectively. Prepared polymeres were analysed and characterized.
In basic medium alpha-trihalogenomethyl-gamma-oxosulfones 1 and 5 preferably react by dehydrohalogenation yielding 2 or 11 after additional cyclisation. With thiolations however mainly an exchange of the sulfonylgroup takes place with formation of the sulfanes 12 and 13.
In this review the literature dealing with the biological effects of 7-oxa-norbornanes is compiled and thus the series of reviews on 7-hetero norbornanes (Chemiker-Ztg. 114 (1990) 53) finished.
(Triphenylphosphine)(selenourea)gold(I) chloride [Ph3PAuSeC(NH2)2]+ Cl- (1) and the corresponding dppm derivative dppm[AuSeC(NH2)2]2(2+) 2 Cl- (2) are prepared from SeC(NH2)2 and the appropriate chloro(phosphine)gold(I) complex. The reaction between 1 and aqueous Na2CO3 leads to the neutral complex mu-selenido{bis[(triphenylphosphine)gold(I)]} (Ph3PAu)2Se (3). An analogous reaction with 2 leads to a dark red oil, which has not yet been characterized. The reaction between 3, Ph3PAuCl, and AgSbF6 leads to the ionic complex [(Ph3PAu)3Se]+SbF6- (4) in good yield. X-ray structure analyses of 1, 2, and 3 confirm the expected linear geometry at the gold atom and reveal short intramolecular Au - Au contacts for 2 and 3. Short nonbonding distances between the nitrogen atoms of the amino groups and the chloride ions in the crystal structures of 1 and 2 probably indicate hydrogen bonds.
Reactions are reported of 1,2-anhydro-3-O(o-ethoxyphenyl)-glycerol and 1-alkylamino-1-deoxy-hexitols to yield amino glycerol derivatives. Furthermore, 1-chloro-2,3-epoxypropane furnished epoxypropyl ethers with galactose or glucose derivatives. On ring-opening reactions of these epoxyethers with isopropylamine or an amino hexitol amino glycerols were formed too.
Intramolecular [4 + 2] cycloaddition reactions with inverse electron demand of the 1,2,4,5-tetrazines 6a-c carrying basic omega-alkyne side-chain dienophiles lead to the novel heterocyclic annulated pyridazines 8,9 and 10 in more than 50 % yield .
Electrolysis of ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA), under carefully controlled potential (e. g. + 1 V anodic), affords 70% of ethylenediamine-N,N'-diacetic acid (EDDA). The further degradation of EDDA, under these conditions, is much slower. The structure of the EDDA metabolite is established unequivocally by ion chromatography and by H-1-NMR spectra, run directly from the electrolyte solutions. A reaction sequence is proposed for the electrolytic degradation of EDTA under potentiostatic control.
