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  • 1
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new synthesis of the title crown via isoxazolo crown ether 7 and macrocyclic bis-β-eneaminoketone 10 is described. 7 can be synthesized in 14% yield by a non-template double-[3+2] cycloaddition of dinitrileoxide 5 prepared in situ from dinitropolyether 19 by dehydration with Ph-NCO and alkyne 6. The compounds 16, 17 and 18 are synthesized by the same synthetic strategy. Comparable IR and 1H NMR spectroscopic data of macrocyclic and non-cyclic compounds show, that macrocyclic conformation stabilizing effects can be ruled out. The structures of the macrocycles 1, 7, 10 and that of the Hg(II)-complex 25, synthesized by reaction of 1 with Hg(OAc)2 were established by single-crystal X-ray structure analyses. Both inter- and intramolecular hydrogen bonds are observed for the macrocyclic bis-β-eneaminoketone 10, whereas only intramolecular hydrogen bonds are formed by 1.In the Hg(II)-complex of 1 the mercury is bonded to two methylene groups. C—Hg—C is almost linear [177(1)°], the mean Hg—C distance amounts to 215(1) pm. In addition to the Hg—C bonds, each Hg makes a short contact to a carbonyl oxygen in a neighbouring molecule in the plane perpendicular to the C—Hg—C axis [Hg(1)—O(1) = 279(1) pm, Hg(2)—O(5) = 284(1) pm].
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 58 (1975), S. 283-292 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 58 (1975), S. 278-283 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the second communication the synthesis of para-substituted 2-methyl-3-phenylpropen(1)-carboxylic acid derivatives is described: Phenylacetone compounds are formed by decarboxylation of a glycidicester; these react according to the Wadsworth-Emmons (Wittig-Horner)-reaction with the corresponding phosphonates to the title compounds. NMR. data show the formation of the steric isomers of 3-Phenyl-2-methyl-propen-1- and 3-Phenyl-2-methylpropen-2-carboxylic acid derivatives.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 60 (1977), S. 2062-2070 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of substituted 2-amino-3-hydroxy-pyridines by nucleophilic displacement of a halogene in halopyridines2-Amino-3,5-dihalogeno-pyridines (halogene: chlorine and/or bromine) react with bases in aqueous-alcoholic or in aprotic polar solvents to the corresponding 2-amino-3-hydroxy-5-halogeno-pyridines. In higher alcohols as solvents pyridyl-alkylethers are formed which then undergo ether-cleavage. As a by-product a mono-dehalogenated compound, 2-amino-5-halogeno-pyridine, is formed, but no 2-amino-3-halogeno-pyridine is dependent on the nature of the leaving group at position 3, on the base, and on the solvent. Copper or its salts accelerate the formation of pyridin-3-ols as well as the dehalogenation of the pyridines at position 3.No evidence has been found for the formation of a 3,4-pyridine by dehydrohalogenation of the halopyridines or for the formation of 2-amino-3-halogeno-5-hydroxy-pyridines by the ANRORC-mechanism. Hence it is assumed that the above mentioned reactions proceed via a radical-anion mechanism.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations on phosphoric acid and thiophosphoric acid esters with a heterocyclic substituent, 10th and last communication. Aza-analogy II: Derivatives of oxazolo[4,5-b]-pyridin-2(3H)-one, an aza-analogue of benzoxazol-2(3H)-one.Oxazolo-[4,5-b]pyridin-2(3H)-one (4), one of the possible aza-analogues of benzoxazol-2(3H)-one (3), is readily prepared starting from furfural (8), using the Clauson-Kaas transformation (oxydative transformation of furans to pyridines with simultaneous incorporation of a nitrogen atom) and proceeding either (1) via furfurylamine (9), 3-hydroxy-pyridine (10), 2-nitro- and 2-amino-3-hydroxy-pyridine (11) followed by ring closure with phosgene or, on shorter routes, directly (2) via 2-amino-3-hydroxy-pyridine (11) or (3) via ∝-methylamino-(fur-2-yl)-acetic acid amide (12) and 3-hydroxypicolinic acid amide (13) followed by a Hofmann degradation. Halogenation and nitration of 4 lead to the 6-substituted derivatives 15-17.A series of thiophosphoric and thiophosphonic acid esters 22-24 with high insecticidal, acaricidal and anthelminthic activities and with extremely low mammalian toxicities up to 〉 5000 mg/kg (rat p.o.) has been disclosed via the N-hydroxymethyl and N-chloromethyl-derivatives 21 of the oxazolopyridin-ones 4, 15, 16 and 17 and the thione 14. These esters are aza-analogues of the known benzoxazolone-insecticide type 1 and present really divergent properties.The vinyl compounds 25 are easily accessible from the oxazolopyridin-ones with vinyl acetate. Addition of halogen to form the 3-(1,2-dihaloethyl)-derivatives 26, however, occasionally is troublesome: 3-(2-halovinyl)-derivatives 27 formed as inherent by-products by dehydrohalogenation handicap further reactions. Some thiophosphoric acid esters 28 and 29 derived from the vinyl compounds 25 and the dihaloethyl compounds 26 resp. are active pesticides too, but their mammalian toxicity ranges from 20-200 mg/kg (rat p.o.), values generally regular in the phosphoric ester field.The one-step condensation of a hetercyclic NH-compound, formaldehyde and a thiophosphoric compound (Stäubli procedure) is not applicable to the preparation of the esters 22 because the acidity of the oxazolopyridin-ones (e.g. 4 and 15) is too high to fulfill the basic requirements of this procedure. An alternative procedure running via the Mannich compounds 31 and 32 fails due to salt formation between Mannich base and thiophosphoric acid.Ring-homologues such as the benzoxazinone derivatives 37 and the pyrido-oxazinone derivatives 40 are not pesticidal.The isomeric oxazolo[4,5-c]pyridin-2-(3H)-one (5) and oxazolo[5,4-b]pyridin-2(3H)-one (7) could not be prepared.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 58 (1975), S. 268-278 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 58 (1975), S. 293-296 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0009-2940
    Keywords: Chlorosilanes, hexacoordinated ; Silicon complexes, octahedral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contributions to the Chemistry of Halogenosilane Adducts, 21.  -  Preparation, Properties, Crystal and Molecular Structure of Dichloro(1,10-phenanthroline)bis(trichlorosilyl)silicon, (SiCl3)2SiCl2 · phenSi3Cl8 · phen (1) is obtained as a stable solid by the reaction of Si3Cl8 with phen. The structure of 1 in solution and its reactions correspond to that of Si3Cl8 · bipy reported earlier (1H-NMR and IR studies). Rearrangement of 1 occurs in solution to give bis(silyl)-substituted 1,2-dihydrophenanthroline. From THF/C6H6 solution crystalline Si3Cl8 · phen · C6H6 (1a) is obtained. The X-ray structure determination shows 1a to be monoclinic, space group P21/n (Z = 4). Phenanthroline is coordinated to the central silicon atom of the trisilane with its plane normal to the linear Si3 chain having two tetrahedral terminal SiCl3 groups. The coordination octahedron is regular.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1277-1283 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Metal Complexes, XX. - Structures of Mercury (II) Derivatives of Nitrogen and Sulfur Analogues of 2,2,6,6,-Tetramethyl-3,5-heptanedioneDipivaloylmethane (2,2,6,6-tetramethyl-3,5-heptanedione, 4) is bound to Hg(II) at the central carbon atom to form structure 2. Substitution of one oxygen by nitrogen leads to a cyclic trimer 16 with equally strong bonds of Hg(II) to C-5 (2.10 Å) and N-1 (2.08 Å) shown by X-ray analysis. Two ligands of the monothio derivative 14 are coordinated nearly linearly (174°) with sulfur to Hg(II) (2.35 Å). The oxygen atoms of the acyl residues are at longer distances (Hg—O in 16 2.53 Å, in 14 2.65 Å). The unsymmetric structure 15 is proposed for the Hg complex with the ligand 9 substituted with nitrogen and sulfur.
    Notes: Dipivaloylmethan (2,2,6,6-Tetramethyl-3,5-heptandion, 4) bindet Hg(II) am mittleren Kohlenstoff zu 2. Ersetzt man einen Sauerstoff durch Stickstoff, so läßt sich ein cyclisches Trimeres 16 isolieren, in dem die Röntgenstrukturanalyse gleichfeste Bindungen von Hg(II) an C-5 (2.10 Å) und N-1 (2.08 Å) anzeigt; die Sauerstoffatome sind weiter entfernt (Hg—O 2.53 Å). Im Monothio-Derivat 14 sind zwei Liganden über die Schwefelatome angenähert linear (174°) an Hg(II) gebunden (Hg—S 2.35 Å). Die Sauerstoffatome der Acylreste sind in beiden Fällen weiter entfernt (Hg—O in 16 2.53 Å, in 14 2.65 Å). Für den Hg-Komplex des Liganden 9 mit Stickstoff und Schwefel wird die unsymmetrische Struktur 15 vorgeschlagen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1525-1529 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Formation of Two Unusual Multinuclear Iron ComplexesThe reaction of KFe(CO)3NO (1) with PhCOCl (2) afforded the dinuclear iron complex 8; in the presence of PPh3 (12), the trinuclear complex 13 was formed. The structures of both compounds were determined by X-ray diffraction.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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