N,N-Dimethylformamide-Promoted Synthesis of Fullerene-Fused Oxazoline Derivatives

Fullerene-fused oxazoline derivatives have been synthesized by many methods, however, the range of substrates is mainly limited to the aromatic substrates. Herein, a method for the synthesis of fullerene-fused oxazoline derivatives has been developed through the N,N-dimethylformamide (DMF)-promoted reaction of C-60 with amides under basic conditions. The method was viable for both aliphatic and aromatic amides, providing the corresponding products in 27%similar to 62% yields. It was found that DMF as a cosolvent could significantly improve the yield of the products. Mechanistic studies indicate that dianionic [60]fullero-oxazoline is key intermediate, and DMF plays a role in stabilizing dianion as demonstrated by in situ visible near infrared spectroscopy and control experiments. The electrochemical property study showed that, to compare with C-60, fullerene-fused oxazoline derivatives of unsubstituted or substituted with an aryl group on oxazoline ring displayed only a slightly changed onset reduction potential, however, that for the derivatives decorated by an alkyl group such as Et on the oxazoline ring was apparently negatively shifted of up to 0.1 V.