Lewis Base-Catalyzed Reaction of Aziridinofullerene with Ureas for the Preparation of Fulleroimidazolidinones

Abstract

The Lewis base-catalyzed double nucleophilic substitution reaction of N-tosylaziridinofullerene with various ureas allows the easy preparation of fulleroimidazolidinones with a high tolerance for functional groups. Alkyl-substituted ureas show better reactivity than aryl-substituted ureas.

Cu(OAc)2-Mediated Reaction of C60 with Ureas for the Preparation of Fulleroimidazolidinones

“…Known products 2a–d , 9 , and 10 were confirmed through comparison of their TLC mobilities with those of the obtained compounds using our previously reported method and their spectral data with those reported in the literature. New compounds 2e , 4a–g , and 4i–k were unambiguously characterized by their HRMS, 1 H NMR, 13 C NMR, and UV–vis spectra (see the Supporting Information).…”

“…Ureas 3i and 3o were synthesized from phenyl isocyanate and amines. Urea 6 was prepared using our previously reported method . Ureas 7 and 8 were synthesized according to the described method …”

“…A mixture of C 60 (54.0 mg, 0.075 mmol), urea 7 (57.2 mg, 0.225 mmol), Phen·H 2 O (44.6 mg, 0.225 mmol), and Cu­(OAc) 2 (41.0 mg, 0.225 mmol) was stirred vigorously in chlorobenzene (13 mL) at 140 °C for 4.5 h. The solvent was evaporated in vacuo , and the residue was purified by column chromatography on silica gel eluting with CS 2 and toluene to give products 9 (4.6 mg, 6%, higher polarity) and 10 (12.2 mg, 19%, lower polarity).…”

“…In the conversion, the TsN unit was reserved in the product and the substrates were limited to aryl isocyanates. Later, we developed the Lewis base-catalyzed double nucleophilic substitution reaction of N -tosylaziridinofullerene with ureas along with the release of the TsN unit, solving the problem of synthesis of alkyl-substituted fulleroimidazolidinones . However, these strategies could not realize the preparation of dialkyl- or diaryl-substituted fulleroimidazolidinones as an electron-withdrawing group on the nitrogen atom was necessary.…”

Synthesis of Imidazolidin-2-ones and Imidazol-2-ones via Base-Catalyzed Intramolecular Hydroamidation of Propargylic Ureas under Ambient Conditions

“…Traditional synthetic routes to imidazolidin-2-ones are mainly based on the carbonylation of diamines, which can require toxic carbonylating agents, high-pressure facilities, and harsh reaction conditions. Metal-catalyzed diamination of olefins and aziridine ring expansion are elegant strategies; however, the widespread application suffers from their inherent sophistication. The intramolecular hydroamidation approach offers a powerful, atom- and step-economical alternative route to easily access richly decorated five-membered cyclic ureas. ,, In this context, propargylureas have been extensively investigated as readily available precursors for the synthesis of both imidazolin-2-ones and imidazolidin-2-ones.…”