Search results for "Bromide"

Studien zum Vorgang der Wasserstoffübertragung 36 [1] Einfluß von Art und Struktur einiger Leitsalze auf die elektrochemische Spaltung von Diarylsulf…

1975

Tensammetrische Messungen bestatigen, das Tetraalkylammoniumsalze in Methanol mit steigender Kettenlange der Alkylreste und wachsender Konzentration zunehmend starker an der Quecksilberoberflache adsorbiert werden. Polarographie und Zyklovoltammetrie der Diarylsulfone 1–8 in Methanol lassen folgende Schlusse zu: 1 Unabhangig von der Alkylkettenlange der Tetraalkylammoniumsalze werden die Diarylsulfone 1–6 nach einem ECE-Mechanismus gespalten. Bei Verwendung von Alkalileitsalzen sind die genannten Sulfone polarographisch inaktiv. 2 Beim 4-Cyano-diphenylsulfon wird mit Tetramethylammoniumchlorid zyklovoltammetrisch keine Reversibilitat des ersten Elektronen ubergangs beobachtet, wohl aber mit…

Stereoselective synthesis of glycosides and anomeric azides of glucosamine

1992

The β-azide of O-acetyl protected N-acetyl glucosamine is efficiently accessible via a phasetransfer-catalyzed reaction of the corresponding glycosyl chloride with sodium azide. The azido group revealed to be a useful anomeric protection for modifications of the protecting group pattern of the glucosamine unit. Exchange of the O-acyl groups by 4-methoxybenzylidene and 4-methoxybenzyl (Mpm) protection delivered regioselectively blocked glucosaminyl azide derivatives. In contrast, the N-phthaloyl protected glucosaminyl azide was obtained quantitatively from the corresponding glycosyl fluoride via a boron trifluoride-promoted reaction with trimethylsilyl azide. N-Phthaloyl glucosaminyl fluorid…

ChemInform Abstract: Stereoselective Synthesis of Glycosides and Anomeric Azides of Glucosamine.

2010

The β-azide of O-acetyl protected N-acetyl glucosamine is efficiently accessible via a phasetransfer-catalyzed reaction of the corresponding glycosyl chloride with sodium azide. The azido group revealed to be a useful anomeric protection for modifications of the protecting group pattern of the glucosamine unit. Exchange of the O-acyl groups by 4-methoxybenzylidene and 4-methoxybenzyl (Mpm) protection delivered regioselectively blocked glucosaminyl azide derivatives. In contrast, the N-phthaloyl protected glucosaminyl azide was obtained quantitatively from the corresponding glycosyl fluoride via a boron trifluoride-promoted reaction with trimethylsilyl azide. N-Phthaloyl glucosaminyl fluorid…

ChemInform Abstract: Multi-Arm 1,2,3-Thiadiazole Systems.

2010

Benzene derivatives 2a–c with 6, 4, and 3 side chains bearing terminal 1,2,3-thiadiazole rings, respectively, have been prepared. Alkaline cleavage of 2a–c led to the corresponding alkynethiolates 6a–c, which were trapped by electrophiles such as benzyl bromide or iodomethane. The method provides an alternative to the thermal or photochemical cleavage of 1,2,3-thiadiazoles to thioketenes, which react further with nucleophiles.

Versuche zur umsetzung von methylendiphenolen mit glucosederivaten und zur kondensation von O-phenylglucosidderivaten

1981

Attempts to apply known methods of glucosidation to oligo[(hydroxyphenylene)methylene]s were not satisfying. The reaction of 4,4'-dimethyl-2,2'-methylenediphenol (1a) with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide gave a monoglucoside in 11% yield. A second attempt, the condensation of suitable O-phenylglucoside derivatives was unsuccessful. From a series of O-phenylglucosides (4) only 4-(2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyloxy)benzylbromide could be condensed with O-(4-hydroxymethylphenyl)-2,3,4,6-tetra-O-acetylglucopyranose to the corresponding diglucoside of 4,4'-oxydimethylenediphenol (7). Condensation reactions of the O-phenylglucoside 4k, to obtain an O-glucosidized poly[…

Darstellung und charakterisierung von einigen neuen bis(1-phenylvinyl)-verbindungen

1974

Einige neue Bis(1-phenylvinyl)-Verbindungen (1b, c und 2a–d) wurden aus den entsprechenden Diacetylverbindungen und Phenylmagnesiumbromid dargestellt. Ihre IR-, NMR-und Massenspektren werden diskutiert. Some new bis(1-phenylvinyl) compounds (1b, c and 2a–d) were prepared from the corresponding diacetyl compounds and phenyl magnesium bromide. Their IR, NMR and mass spectra are discussed.

Physicochemical Properties of New Dicationic Ether-Functionalized Low Melting Point Ammonium Salts

2010

Eleven new and one previously known but insufficiently characterized dicationic quaternary ammonium (QA) salts were synthesized and characterized. They contain an ethoxy ethyl group either in a side chain and/or as spacer of the diammonium cation and have bromide, hexafluorophosphate (PF6–), bis(trifluoromethanesulfonyl)imide (TFSI), or trifluoromethanesulfonate (TFMS) as an anion. 1H and 13C techniques, mass spectrometry, and elemental analysis together with X-ray diffraction and thermoanalytical methods were used for their characterization both in the liquid and solid state. In addition, residual water content and viscosity measurements were made for the two room temperature ionic liquid…

1963

Es wird gezeigt, das sich e-Caprolactam mit wasserfreiem Bromwasserstoff kationisch polymerisieren last und die dabei gebildeten Polymeren die Struktur von N-(Poly-e-aminocaproyl)-caprolactamen besitzen. Die charakteristische Diacylimidstruktur wird IR-spektroskopisch, durch die Hydroxamsaurereaktion und durch alkoholytische Abspaltung des C-terminalen Lactamringes nachgewiesen. Oligomerengemische, die durch kurzzeitige Umsetzung molarer Mengen an Caprolactam und Initiator bei 175–200°C erhalten werden, konnen durch Hochspannungspapierelektrophorese in einheitliche Individuen aufgetrennt werden. Die Umsetzung mit Hydroxylamin fuhrt zu Oligo-e-aminocapronhydroxamsauren, die sich mit Hilfe au…

Synthesis and Properties of Some Simple Organotitanium Compounds

1986

Before embarking on a detailed discussion of the titanation of carbanions, synthetic and physical organic aspects of several typical organotitanium (IV) compounds shall be surveyed, including thermal stability, aggregation state, X-ray structural data and bond energies. Some of this information is useful in understanding reactivity and selectivity in reactions with organic substrates. Low valent Ti (II) and Ti (III) shall be mentioned only on passing; the interested reader is referred to reviews [1].

Polymere ester von Säuren des phosphors, 5. Ringöffnende polymerisation des 2-phenoxy-1,3,2-dioxaphospholan durch Michaelis-Arbuzov-reaktion

1977

2-Phenoxy-1,3,2-dioxaphospholane (14) was polymerized by benzyl halogenides at temperatures between 120 and 200°C. It was found that the main chain consists predominantly of unexpected ethylene 1,2-ethanediphosphonate units 7; only about 10% of the monomer was incorporated as the expected 2-hydroxyethanephosphonate structure. An insertion mechanism, proposed by Harwood and Patel for the analogous polymerization of 2-phenyl-1,3,2-dioxaphospholane, does not agree with our experimental results. A hypothesis is developed involving a two step addition process, which exclusively occurs at the chain end. Alternating, one monomer molecule is added by a normal Michaelis-Arbuzov-reaction, and then a …