SYNTHESIS OF FULLERENE AMINO-ACID DERIVATIVES BY DIRECT INTERACTION OF AMINO-ACID ESTER WITH C-60

Amino acid esters react with C-60 both thermally and photochemically t o give different products. Refluxing a mixture of C-60 and glycine eth yl ester afforded C-60(Me(2)CHNHCHCOOEt) 1, whereas irradiation of the same mixture produced C-60(EtOOCCHNHCHCOOEt) 2b as tile main product. Photochemical reactions between C-60 and sarcosine esters yielded two pyrrolidine derivatives C-60(CH2N(Me)CHCOOR)3 and C-60(ROOCCHNHCHCOOR ) 2 (R = Me, Et, CH(2)Ph). Compound 2a is also prepared from the photo chemical reaction between C-60 and iminodiacetic methyl ester in high yield. These ester derivatives are difficult to hydrolyze in excess mi neral acids. The fullerene dicarboxylic acid C-60(HOOCCHNHCHCOOH) 5 is synthesized from the tert-butyl derivative C-60((t)BuOOCCHNHCHCOO(t)B u) 4. A possible radical reaction mechanism for the photochemical reac tions is proposed which involves an unprecedented C-N bond breakage.