Azobenzenes are versatile photoswitches that have found widespread use in a variety of fields, ranging from photopharmacology to the material sciences. In addition to regular azobenzenes, the cyclic diazocines have recently emerged. Although diazocines have fascinating conformational and photophysical properties, their use has been limited by their synthetic accessibility. Herein, we present a general, highyielding protocol that relies on the oxidative cyclization of dianilines. In combination with a modular substrate synthesis, it allows for rapid access to diversely functionalized diazocines on gram scales. Our work systematically explores substituent effects on the photoisomerization and thermal relaxation of diazocines. It will enable their incorporation into a wide variety of functional molecules, unlocking the full potential of these emerging photoswitches. The method can be applied to the synthesis of a new cyclic azobenzene with a nine-membered central ring and distinct properties.
Herein we demonstrate the first electrochemical synthesis protocol of symmetrical sulfamides directly from anilines and SO2 mediated by iodide. Sulfamides are an emerging functional group in drug design. Highlights are...
Scheme 1. Selected approved drugs containing nitro functionalities.Scheme 2. Traditional approach (electrophilic aromatic substitution) in comparison to the electrochemical nitration with nitrite (this work); C gr = graphite.
We successfully achieved methylation of various SiO2 sources to cyclic methylsiloxanes via electroreduction reaction. Contrary to previous assumptions, the reaction does not start from methanol as methyl radical source, that results in methoxylation of the electrolyte solvent. Methylammonium cations were found to enable the direct conversion, strongly dependent on the radical intermediate stabilization by the electrolyte. THF/Bu4NCF3SO3 is the sole applicable system with yields below 14 % referred to the methylammonium cations for the highest amount of product obtained so far. Mechanistic insights show that methylation does not occur via the supposed hydrolysis of dimethoxydimethylsilane intermediate, but via a direct conversion reaction, as comparative studies of a Fenton‐type procedure clearly indicate. Further, cyclic methylsiloxane products are prone to subsequent electrochemical equilibration, strongly directed by the electrolyte solvent.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.