Search results for "BOND"

ChemInform Abstract: Cycloaddition of Benzothiete and Electron-Deficient Nitriles.

2010

The o-quinoid 8π electron system 2, generated by thermal ring opening of benzothiete (1), enters regio-specific [8π + 2π] cycloaddition reactions with electron-deficient nitriles 3a-d, yielding the 4H-1,3-benzothiazines 4a-d. A competitive dimerization of 1 leads to 1,5-dibenzo[b,f]dithiocin (5). Depending on the nitrile further competitive or subsequent reactions (2 + 3b 7b, 2 + 3d 4d 8d) can occur. The cycloadducts 10e and 11e gained from 3e anticipate a primary cleavage of 3e to methylisothiocyanate 9e which reacts at the CN double bond as well as at the CS double bond.

N-{(Z)-2-[1-(Triisopropylsilyl)-1H-indol-3-yl]-2-(triisopropylsilyloxy)vinyl}-2-(3,4,5-trimethoxyphenyl)acetamide

2007

The molecular structure of the title compound, C39H62N2O5Si2, obtained as an unexpected side product, was determined in the course of our studies on the synthesis of N-triisopropyl-1H-indol-3-yl derivatives. Interestingly, although the triisopropylsilyl group was intended as a temporary protecting group, the compound comprises a remarkably stable N—Si bond. The vinyl C=C double bond possesses a Z configuration.

Synthesis of ?-fucosyl glycosides and disaccharides using 4-methoxybenzyl (Mpm) protected fucosyl donors

1992

The 4-methoxybenzyl (Mpm) group removable by selective oxidation was applied as a nonneighbouring-group-active protection of fucose hydroxy functions in the stereoselective synthesis of α-fucosides of acceptors containing double bonds sensitive to hydrogenation. With this aim, the synthesis of the α-fucosyl chloride (4) carrying the acidsensitive Mpm protection was elaborated.

Polymerisation von äthylenoxid mit dem kaliumalkoholat von 4-benzolazo-benzylalkohol. I. Der anionische polymerisationsmechanismus

1966

Athylenoxid last sich mit dem Kaliumalkoholat von 4-Benzolazo-benzylalkohol polymerisieren. Dabei erhalten die Polyathylenoxide eine zusatzliche UV-Absorption, die auf covalent eingebaute C6H5NNC6H4(p) CH2O-Gruppen zuruckzufuhren ist. Wenn der ubliche Mechanismus der anionischen Polymerisation gilt, sollte jedes Polyathylenoxidmolekul eine besonders absorbierende Endgruppe enthalten. Fraktioniert man die mit dem Alkoholat hergestellten Polyathylenoxide, so ist die Extinktion bei gleicher Polymerkonzentration nicht wie erwartet um so groser, je kleiner das Molekulargewicht ist. Bestimmt man ferner quantitativ den Gehalt an C6H5NNC6H4(p) CH2O-Gruppen in Polyathylenoxidfraktionen und nimmt ein…

Elucidation of the Conformational Freedom of Ferrocene Amino Acid (Bio)Conjugates: A Complementary Theoretical and Experimental Approach

2011

1982

p-Cresol and eight oligo[(hydroxyphenylene)methylene] compounds 1b–e and 4a–d could be esterified with good yields with acryloyl chloride or propionyl chloride, respectively, in the presence of triethylamine. The simple and multiple acrylates and propionates were characterized by determination of their molar masses, elemental analyses, hydrogenation of the CC double bonds in the acrylate groups, and by their IR- and UV-spectra. No steric hindrance could be ascertained. Acrylates with more than three phenolic units in their molecules were found to have a range of melting, whereas all the propionates possess sharp melting points. This can be explained by polymerization of the acrylates which …

Einführung einer Dreifachbindung in das Bicyclo[6.1.0]nonan-Gerüst

1987

Ausgehend von den auf verschiedenen Wegen zuganglichen Ketonen 1a–c wird die Einfuhrung einer Dreifachbindung in das Bicyclo[6.1.0]nonan-Gerust mit Hilfe der Selenadiazol-Methode untersucht. Dabei Konnen die hochgespannten Bicyclo-[6.1.0]nonine 2a und 2b in reiner Form isoliert werden. Masgeblich fur die Position der Dreifachbindung ist die Regioselektivitat der Ringschlusreaktion bei der Selenadiazolbildung. Introduction of a Triple Bond into the Bicyclo[6.1.0]nonane Skeleton The introduction of a triple bond into the bicyclo[6.1.0]nonane skeleton is investigated by applying the selenadiazole method to the ketones 1a–c, accessible on different pathways. The highly strained bicyclo[6.1.0]no…

NLO Polymers Containing as Active Chromophore in Dandionylpyridinium, Betaine Units: Synthesis, Modeling and Characterization

2000

In present article we report about synthesis, quantum chemical model calculations, non-linear optical characterization and dependencies of the surface potential changes on irradiation with light of novel polyurethane based polymers, namely a bipolar organic compound N-(indan-1,3-dion-2-y1)-4-N’,N’dialkylaminopyridinium betaine (IPB) containing charged electron donor and electron acceptor groups covalently bonded to polyurethane polymer backbone. These newly synthesized IPB containing polymers could be regarded as a promising thermally stable organic non-linear optical materials with long time performance for photonic applications.

Die zweifache unterdrückung der polymerisation einiger bis(methacrylsäureester) mittels radikalischer additionsreaktionen

1973

Aus Hydrochinon, Resorcin, Dihydroxydiphenylen und Dihydroxynaphthalinen wurden mit Methacrylsaurechlorid Bis(methacrylsaureester) hergestellt. Setzte man diese in siedendem Benzol mit groser Verdunnung gelosten Ester dem Angriff von Radikalen aus α.α′-Azoisobuttersauredinitril (Primarradikale) aus, dessen Uberschus in Beziehung zum Ester mindestens zwanzigfach molar war, so erhielt man mittels saulenchromatographischer Trennung Verbindungen, bei denen je olefinische Doppelbindung zwei Primarradikale addiert waren (unterdruckte Polymerisation). Die Struktur dieser Produkte wurde mittels Elementaranalyse, Molekulargewichtsbestimmung, IR- und 1H-NMR-Spektren bewiesen. Demnach kann die Polymer…

Molecularly imprinted polymers (MIPs) against uracils: Functional monomer design, monomer-template interactions in solution and MIP performance in ch…

2002

AbstractThe interaction of N1-substituted uracils (cyclohexyl (1) and benzyl (2)) with three polymerisable recognition elements, the novel monomers 9-(3/4-vinylbenzyl)adenine (3) and 2,6-diamino-9-(3/4-vinylbenzyl)purine (4) and the previously synthesised monomer 2,6-bis(acrylamido)pyridine (5), has been studied via1H NMR in deuterio-chloroform solution. MIPs against (2) have been prepared using each of the monomers and tested in the chromatographic mode. The effect of the number and type of hydrogen bonds formed between the templates and the functional monomers is reflected in the values of the apparent association constants obtained from the solution study and by the performance of the su…