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Showing 1 to 18 of 18 for “"photocycloaddition"”.
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The mechanism of an unusual benzo/benzo photocycloaddition reaction : photophysical and photochemical investigation of [3.3] orthocyclophanes with two face-to-face preoriented benzenoid chromophores
The clean and reversible [6pi+6pi] photocycloaddition (= PCA) in a [3.3] orthocyclophane (= OCP), in which two benzene chromophores are rigidly held in an unusually proximate, strongly interacting, face-to-face orientation, is the key step in the Pagodane - Dodecahedrane - Scheme. Due to the …
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ΕΝΔΟΜΟΡΙΑΚΗ ΦΩΤΟΚΥΚΛΟΠΟΙΗΣΗ ΤΗΣ ΚΑΡΒΟΝΗΣ ΠΡΟΣ ΚΑΡΒΟΝΟΚΑΜΦΟΡΑ
THE QUANTUM YIELDS OF THE PHOTOCYCLOADDITION OF CARVONE (I) TO CARVONECAMPHOR (2) (TYPE) HAVE BEEN DETERMINED IN NON POLAR AND POLAR SOLVENTS, UNDER NITROGEN AND IN AIR-EQUILIBRATED SOLUTIONS. QUENCHING BY OXYGEN HAS BEEN OBSERVED ONLY IN NON POLAR SOLVENTS, BENZENE 01 --> 2=0.0025 UNDER NITROGEN …
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Approaches to the Synthesis of the Ophiobolin Ring System
… involved the application of an intramolecular photocycloaddition reaction of (DELTA)('(alpha),(beta))-butenolide derivatives and the reductive cleavage of the derived cyclobutanes. This procedure provides a novel method for effecting two-carbon ring expansion.
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THREE STUDIES OF 2-PYRIDONE PHOTOADDUCT REACTIVITY
2-Pyridones such as iii undergo efficient [4+4] photocycloaddition reactions, yielding strained tricyclic cyclooctadiene structures iv and v, with functionality at every carbon. As part of a program to develop the chemistry of these complex adducts, three studies have been conducted. Halogenation …
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Dearomative reduction of arenes through the use of arenophiles & studies towards the synthesis of cardiotonic steroids calotropin and calactin
… was developed. Cheap feedstock arenes undergo photocycloaddition with MTAD, and the cycloadduct can be treated further to furnish novel 1,3-cyclohexadienes or 1,4-diamino-2- cyclohexenes. The utility of this method is shown in the synthesis of a natural product in two steps from naphthalene. …
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SYNTHESIS OF NATURAL PRODUCT NEPETANUDONE THROUGH THERMALLY FORBIDDEN [4Π+4Π] CYCLOADDITION IN THE PRESENCE OF LIGHT
… for the biosynthesis of Nepetanudone through the photocycloaddition reaction of two 5,9-dehydronepetalactones.
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Untersuchungen zum Einfluss von Substituenten auf die spektralen und photochemischen Eigenschaften sowie die Molekülstruktur von Dibenz[b,f]azepinen
… die Photodimerisierungsreaktion (2[pi] + 2[pi]Photocycloaddition) der eingesetzten Verbindungen in Abhängigkeit vom Substitutionsmuster sowie den Umgebungsbedingungen. Es konnte gezeigt werden, dass lediglich Verbindungen mit Acylsubstituenten am Azepinstickstoff photodimerisieren können, …
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Nahgeordnete Bisdiazene : Synthesen, Photochemie, Elektrochemie: In-Plane sigma-Delokalisierung in 4N-Ionen
… Reaktionswege, nicht aber eine [2p+2p]-Photocycloaddition. <br> <br>Die Reduktion der Bisdiazene durch Elektronenübertragung führt über nichtklassische, cyclisch delokalisierte 4N/5e-Radikalanionen (grün) zu Dianionen (rot), die ein 4N/6e-s-bis-homoaromatisches Vierzentrensystem …
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Functional Materials From Self-Assembled Macrocycles
… into column through C-H---O hydrogen bonds. Photocycloaddition and hydrolysis of this carbonate macrocycle yields a tetra-alcohol structure that could act as a rigid build block for more complex organic structure or MOFs. </p> <p>Conjugated microporous polymers (CMPs) have been the subject of …
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Developing unstrained alkenes and alkynes for bioorthogonal chemistry
… undergo an acetophenone-mediated hetero-[2+2] photocycloaddition with maleimide derivatives, expanding the toolbox of photo-triggered chemistry for protein modification. The potassium arylethynyltrifluoroborate handle was also found reactive in copper(I)-catalyzed alkyne-azide cycloaddition …
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PHOTOCHEMICAL AND TITANIUM (II) MEDIATED METHODS FOR THE SYNTHESIS OF COMPLEX MOLECULAR SCAFFOLDS
… applications and 2) utilizing a [4 + 4] photocycloaddition of 2-pyridone-enolynes to access functionally rich cyclooctanoids that are capable of further photochemical transformations into even more complex molecular scaffolds. The titanium (II) mediated Kulinkovich reaction traditionally …
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Photochemistry of dibenzobarrelenes and [alpha]-adamantyl acetophenones in both the solution and crystalline state
… 199 were synthesized for the solid state [4 +4] photocycloaddition reactions. It was found that pyrazinone 197 gave high optical yield of the photoproduct 198 (95% e.e.); this result was discussed based on the crystal structure of the substrate 197. Pyrazinethione 199 was found photochemically …
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Synthetic Applications Of The Photochemical Cycloaddition Reactions Of N-acylindoles And Conformational Studies Of The Cycloadducts
… present in these compounds.;Intramolecular photocycloaddition of N-carboxyindole anhydride (NCIA) has been found to give two intramolecular cycloadducts. The structure of one of the intramolecular photocycloadducts was determined by conversion to the major intermolecular photodimer obtained …
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Second-site inhibitors of the estrogen and androgen hormone receptors
… isolated. This compound stemmed from the photocycloaddition of 2,4-dichloro-6-styrylpyrimidine, an intermediate in the synthesis for a number of the pyrimidine-core coactivator binding inhibitors, which occurred accidentally under ambient conditions. Based on this observation, six …