Search results for "polymer chemistry"

Oxidative halogenation of substituted pyrroles with cu(II). Part I. Bromination of some 3-acetylpyrroles

1990

3-Acetylpyrroles are brominated with copper(II) bromide. The reaction afforded almost quantitatively only nuclear monobromination. Evidence for the structures of final compounds was by mass spectrometry, 1 H-nuclear magnetic resonance, ir, and elemental analysis

1969

Rational Design of an Enneanuclear Copper(II) Complex with a Metallacyclophane Core

2004

1983

The kinetics of the electrophilic bromination of 17 oligonuclear phenolic compounds with molecular bromine in acetic acid were studied at 22°C. Some of these compounds, consisting of up to 6 phenolic units, which are linked in ortho-position by methylene bridges, and having only one (or two) reactive ortho-position(s) at the end of the molecule, were synthesized for the first time. It could be shown, even for hexanuclear compounds, that the variation of substituents at one end of the molecule leads to a change in the reactivity at the other end, that means over a distance of 22 nonconjugated covalent links. So far, this can be explained only by a chain of intramolecular hydrogen bonds betwe…

Covalently linked multi-calixarenes

1998

Abstract ipso-Nitration of t-butyl calix[4]arene tetraethers and subsequent hydrogenation provides an easy access to monoamino calix[4]arenes. Reaction with di- and triacid chlorides leads to various double- and triple-calix[4]arenes. With tetraacid chlorides derived from calix[4]arenes in the cone- or 1,3-alternate-conformations penta-calix[4]arenes are available as molecularly uniform species, which may be regarded as the first generation of calix[4]arene based dendrimers. The structure of the mononitro tetraester derivative, which may serve as a general building block has been confirmed by single crystal X-ray analysis.

1972

Umsetzungen an höhermolekularen, molekulareinheitlichen phenol-formaldehyd-kondensaten

1960

An in eindeutiger Synthese und im praparativen Masstab zuganglich gewordenen hohermolekularen, molekulareinheitlichen Phenol-Formaldehyd-Kondensaten (Mol.-Gew. bis zu 1500) wird die Acetylierung, die Umsetzung mit Diphenylcarbamidsaure-chlorid zu Poly-[N-diphenyl-]urethanen und mit Formaldehyd und Dimethylamin zu MANNICH-Basen untersucht. Bei den zwei ersten Umsetzungen wird mit Hilfe der Elementaranalyse bzw. der Acetylbestimmung sowie der UR-Spektren zu unterscheiden versucht, ob alle Hydroxygruppen einer Molekel umgesetzt werden konnen. Die Elementaranalysen der erhaltenen MANNICH-Basen zeigen, das eine vollstandige Einfuhrung von Endgruppen (kettenanaloge Umsetzung) gelungen ist. Higher…

Ringoffene Serotonin-Analoga, 2. Mitt.1) Synthese von 3-(2-Aminophenyl)-propanamin- und 1-(N-Piperidino)-3-(2-aminophenyl)-3-oxo-propan-Derivaten

1983

Die Darstellung der Titelverbindungen gelingt via Mannich-Reaktion beim Einsatz geeignet substituierter Acetophenone. Die Gewinnung von 2 und seiner Derivate erfordert zusatzlich die nachfolgende durchgreifende Hydrierung der Carbonylgruppe der entsprechenden Mannichbasen. Ring-Opened Analogues of Serotonine, II: Synthesis of 3-(2-Aminophenyl)propanamine and 1-(Piperidin-1-yl)-3-(2-aminophenyl)propan-3-one and Their Derivatives The synthesis of the title compounds was achieved by Mannich reaction of suitably substituted acetophenones. The preparation of 3-(2-aminophenyl)propanamine and its derivatives requires complete hydrogenation of the carbonyl group of the Mannich bases.

1,4,8,11-Tetrakis(4-ferrocenyl-3-azabutyl)-1,4,8,11-tetraazacyclotetradecane as a ferrocene-functionalised polyammonium receptor for electrochemical …

1999

The interaction of the ferrocene-functionalised polyaza receptor 1,4,8,11-tetrakis(4-ferrocenyl-3-azabutyl)-1,4,8,11-tetraazacyclotetradecane (L1) with sulfate, phosphate and ATP has been studied potentiometrically in THF–water 70∶30 v/v (0.1 mol dm–3 tetrabutylammonium perchlorate, 25 °C). The molecular structure of the free receptor has been determined by single-crystal X-ray procedures. An electrochemical study on L1 as a function of the pH has been carried out in THF–water 70∶30 v/v in the presence of the sulfate, phosphate and ATP anions. The potential use of L1 as an anion sensing receptor is discussed in terms of the electrochemical and potentiometric data and its behaviour is compar…

Über den thermischen abbau des poly(ɛ-caprolacton)s

1977

The thermal and electron impact induced degradation reactions of poly(e-caprolactone) {poly[oxy(1-oxohexamethylene)]} were investigated in a mass spectrometer. It can be shown that the favorated thermal degradation reaction is the cleavage of the ester bond and formation of ω-hydroxyl and ketene endgroups (Eq. (iii)) and with a lower intensity the cleavage of the OCH2-bond and formation of carboxyl-and pentenyl endgroups (Eq. (vii)). After electron impact and fragmentation of the pyrolysis products to carboxonium ions an elimination of caprolactone via a “zip”-mechanism can be observed (Eq. (v)).