Mesoporous carbon nitride (mpg-C(3)N(4)) polymer can function as a metal-free photocatalyst to activate O(2) for the selective oxidation of benzyl alcohols with visible light, avoiding the cost, toxicity, and purification problems associated with corresponding transition-metal systems. By combining the surface basicity and semiconductor functions of mpg-C(3)N(4), the photocatalytic system can realize a high catalytic selectivity to generate benzaldehyde. The metal-free photocatalytic system also selectively converts other alcohol substrates to their corresponding aldehydes/ketones, demonstrating a potential pathway of accessing traditional mild radical chemistry with nitroxyl radicals.
Coupling on sunshine: A simple and efficient synthesis of benzoxazoles, benzimidazoles, and benzothiazoles is realized through a one‐pot preparation driven by a photocatalytic cascade reaction. Carbon nitride and visible light are employed to achieve this metal‐free aerobic oxidation of amines to imines (see scheme; mpg‐C3N4=mesoporous graphite carbon nitride).
Ein echter Sonnenschein: Eine einfache und effiziente Synthese von Benzoxazolen, Benzimidazolen und Benzothiazolen gelingt mithilfe eines Eintopfverfahrens, das durch eine photokatalytische Kaskadenreaktion angetrieben wird. Bei dieser metallfreien aeroben Oxidation von Aminen zu Iminen kommen Kohlenstoffnitrid und sichtbares Licht zum Einsatz (siehe Schema; mpg‐C3N4=mesoporöses graphitisches Kohlenstoffnitrid).
Azodicarboxylates have found applications in electrophilic amination reactions and in pericyclic reactions. The nucleophilic trigger in Mitsunobu reactions, that is, the zwitterion formed from triphenylphosphine and dialkyl azodicarboxylate, has been utilized recently in various heterocyclic constructions. This Focus Review summarizes the potential utility of azodicarboxylates in various carbon-nitrogen bond-forming reactions.
The synthesis of new C-6 1,2,3-triazole adenosine derivatives via microwave assisted 1,3-dipolar cycloaddition as key step is described. The binding on membranes of cells that over express A(1) adenosine receptors (A(1)AR) was also evaluated. Among them, four compounds increased cAMP production, in a dose-dependent manner acting as antagonists of the A(1)AR, while two compounds act as agonists.
Two unexpected transformations: The reaction of the Huisgen zwitterion derived from triphenylphosphane and diisopropyl azodicarboxylate (DIAD) with chalcones affords functionalized pyrazolines. In contrast, the reaction with dienones affords pyrazolopyridazines, presumably by Diels–Alder reaction of the initially formed pyrazoline with excess DIAD (see scheme).
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