Solvent-free reactions of fullerenes and N-alkylglycines with and without aldehydes under high-speed vibration milling

The solvent-free reactions of fullerenes and N-alkylglycines with and without aldehydes (RCHO) under high-speed vibration milling (HSVM) conditions have been investigated. Fulleropyrrolidines (C60(CH2N(CH3)CHR), R=H (), C6H5 (), p-NO2–C6H4 (), p-CH3O–C6H4 (), p-(CH3)2N–C6H4 ()) were obtained in moderate yields from reactions of C60 with aldehydes and N-methylglycine (Prato reaction). In all these solvent-free reactions, was found to be formed besides , indicating that fullerenes can react with N-substituted glycines in the absence of aldehyde to give fulleropyrrolidines. For this novel reaction, a possible reaction mechanism involving an electron transfer process has been proposed. Intrigued by this observation, the dependence of the yield on the reagent ratio for the reaction of C60 with paraformaldehyde and/or N-methylglycine was examined to search the optimal conditions. The reaction of C70 with paraformaldehyde and/or N-methylglycine under HSVM conditions was also studied and was found to give the positional isomers of [70]fulleropyrrolidines.