Search results for "HALO"
showing 10 items of 2623 documents
Identification of the Iodination and Bromination Products of 3-Hydroxybenzaldehyde: Preparation of 5-Hydroxy-2-iodobenzaldehyde
2017
The monohalogenation products of 3-hydroxybenzaldehyde (1) are useful synthons for the preparation of more complex molecules.1–4 For example, the introduction of a halogen allows the use of a Suzuk...
Iod-induzierte stereoselektive Carbocyclisierungen – Beispiele für eine breit anwendbare, neue Methode zur Synthese von Cyclohexan- und -hexen-Deriva…
1988
Impact of Starmerella bacillaris and Zygosaccharomyces bailii on ethanol reduction and Saccharomyces cerevisiae metabolism during mixed wine fermenta…
2021
AbstractThe bulk of grape juice fermentation is carried out by the yeast Saccharomyces cerevisiae, but non-Saccharomyces yeasts can modulate many sensorial aspects of the final products in ways not well understood. In this study, some of such non-conventional yeasts were screened as mixed starter cultures in a fermentation defined medium in both simultaneous and sequential inoculations. One strain of Starmerella bacillaris and another of Zygosaccharomyces bailii were chosen by their distinct phenotypic footprint and their ability to reduce ethanol levels at the end of fermentation, particularly during simultaneous vinification. S. bacillaris losses viability strongly at the end of mixed fer…
Der nachweis der kettenstruktur von aus p-kresol und formaldehyd aufgebauten mehrkernverbindungen. I. Durch verschiedene synthese und identifizierung…
1962
In ubersichtlicher, mehrfacher Synthese werden homologe Mehrkernverbindungen aufgebaut, die aus uber Methylenbrucken verbundenen p-Kresolbausteinen bestehen (Novolak-Struktur). Die verschiedenen, zu einer Mehrkernverbindung fuhrenden Synthesen geben identische Verbindungen. Die Kettenstruktur dieser Mehrkernverbindungen kann durch kettenanaloge Enthalogenierungen, durch geeignete Kondensationen (Gl. (1)) sowie durch entsprechende Substitutionsbanden in den IR-Spektren der Verbindungen nachgewiesen werden. By means of rational, multiple syntheses, homologous polynuclear compounds were prepared, consisting of p-cresol units linked by methylene bridges (Novolac structure). The different ways o…
ChemInform Abstract: One-Pot Synthesis of Pyrrole-2-carboxylates and -carboxamides via an Electrocyclization/Oxidation Sequence.
2015
An electrocyclic ring closure is the key step of an efficient one-pot method for the synthesis of pyrrole-2-carboxylates and -carboxamides from chalcones and glycine esters or amides. The 3,4-dihydro-2H-pyrrole intermediates generated in situ are oxidized to the corresponding pyrroles by stoichiometric oxidants or by catalytic copper(II) and air in moderate to high yields. A wide range of functional groups are tolerated, and further combination with an in situ bromination gives access to polyfunctional pyrrole scaffolds.
Hierarchical halogen bonding induces polymorphism
2009
Co-crystals of 1-iodo-3,5-dinitrobenzene and 1,4-diazabicyclo[2.2.2]octane manifest either two strong or one strong and one weak intermolecular 2 : 1 halogen bond (XB) motifs in polymorphic structures I and II, respectively, whereas weaker XB-donor 4,4-bipyridine just forms 1 : 1 structure III with one strong halogen bond.
Fluorinated Pyrazoles and Indazoles
2014
The synthesis of fluorine containing pyrazoles has been boosted in the past decades due to the interesting properties that confer these building blocks in pharmaceutical and agricultural active ingredients. There are two main methods for the synthesis of fluorine-containing organic compounds, namely, the direct replacement of an atom or functional group such as diazo, hydroxyl, halogen or hydrogen by fluorine, and the modification of fluorine-containing building blocks. In the case of fluorinated pyrazoles the latter approach is the most commonly applied. This chapter deals primarily with the pivotal procedures that allow the preparation of fluoro- and fluoroalkyl- pyrazoles. Their benzocon…
ChemInform Abstract: Iodocyclization of o-Alkynylbenzamides Revisited: Formation of Isobenzofuran-1(3H)-imines and 1H-Isochromen-1-imines Instead of …
2013
Remarkably, isobenzofuran and benzopyran derivatives are obtained by the title reaction and not as described in earlier publications five- or six-membered lactams.
Tristriazolotriazines with π-Conjugated Segments: Star-Shaped Fluorophors and Discotic Liquid Crystals
2012
C3-symmetrical tristriazolotriazines substituted with phenylene rings carrying lateral flexible alkoxy side chains were prepared via condensation/ring transformation of cyanuric chloride and tetrazoles. These star-shaped, planar compounds can form broad thermotropic mesophases. Due to the extensive π-conjugation, these compounds are highly emissive and the octupolar donor-acceptor electronic structure results in non-linear optical properties like solvatochromism. Brønstedt acids provoke halochromism of the absorption and of the fluorescence.