Azidoimidazolinium Salts: Safe and Efficient Diazo‐transfer Reagents and Unique Azido‐donors

Abstract

2-Azido-1,3-dimethylimidazolinium chloride (ADMC) and its corresponding hexafluorophosphate (ADMP) were found to be efficient diazo-transfer reagents to various organic compounds. ADMC was prepared by the reaction of 2-chloro-1,3-dimethylimidazolinium chloride (DMC) and sodium azide. ADMP was isolated as a crystal having good thermal stability and low explosibility. ADMC and ADMP reacted with 1,3-dicarbonyl compounds under mild basic conditions to give 2-diazo-1,3-dicarbonyl compounds in high yields, which were easily isolated in virtue of the high water solubility of the by-products. ADMP showed high diazo-transfer ability to primary amines even in the absence of metal salt such as Cu(II). Using this diazotization approach, various alkyl/aryl azides were directly obtained from their corresponding primary amines in high yields. Furthermore, naphthols reacted with ADMC to give the corresponding diazonaphthoquinones in good to high yields. In addition, 2-azido-1,3-dimethylimidazolinium salts were employed as azide-transfer and migratory amidation reagents.

Identifying high-mobility tetracene derivatives using a non-adiabatic molecular dynamics approach

“…The criteria for selecting the aforementioned molecular crystals is the proven capability of high-yield synthesis and pronounced room temperature structural stability. 27,[32][33][34] Further information is listed in Table S1 in the ESI. † Initial configurations are based on experimental crystal structures.…”

“…† Initial configurations are based on experimental crystal structures. 27,[32][33][34] Every system has been equilibrated by means of periodic molecular dynamics (MD) simulations in the canonical statistical ensemble at room temperature for 1 ns, followed by production MD simulations for 1 ns in the microcanonical statistical ensemble (NVE). From each NVE simulation, a selection of uncorrelated trajectories was singled out, resulting into a swarm of 1024 independent non-adiabatic molecular dynamics…”

“…31 In the case of alkylated tetracenes, a wide collection of soluble molecules is currently accessible via Diels-Alder cycloaddition reactions. 32 Functionalized tetracene cores selfassemble into well-ordered molecular wires that -in turnform robust molecular crystals made up by tightly packed molecular pillars with tunable optical properties. 33 The length and morphology of the alkyl side chains and the functionalization scheme, i.e.…”

“…the number of peripheral grafting sites and their relative positions on the polyaromatic core, affect vital molecular crystal properties and mechanisms, such as the molecular wire packing, the intracolumnar tetracene stacking patterns, and the molecular crystal melting point. 33,34 Although the majority of the literature on alkylated tetracenes is focused on solid-state optical properties, 27,[32][33][34] their dense packing suggests that they should be excellent candidates for high-mobility 1D materials as well. However, their potential in this respect has not yet been addressed in the literature and will be investigated in the present paper.…”

Synthesis and Characterization of Soluble Directly 2,2′‐Linked Tetracene Dimer

“…We recently prepared various tetracene derivatives with alkyl [5] and ester [6] substituents, resulting in improved solubility in organic solvents as well as controlled acene arrangements in the solid state. [7] Thus, we speculated that πextended tetracene derivatives, oligomers, and polymers are promising materials in view of the aforementioned applications.…”