Fullerene lipids: Synthesis of novel nitrogen‐bridged [60]fullerene fatty ester derivatives

• Published in: Lipids 2001-04, Vol.36 (4), p.421-426
• Main Authors: Lie Ken Jie, Marcel S. F., Cheung, Sunny W. H., Ho, Janette C. M.
• Format: Article
• Language: English
• Subjects: Derivatives; Fullerenes; Lipids; Nitrogen; NMR; Nuclear magnetic resonance; Toluene
• ISSN: 0024-4201; 1558-9307
• DOI: 10.1007/s11745-001-0738-0

Reactions of methyl 6‐azido‐hexanoate, 8‐azido‐octanoate, and 12‐azido‐dodecanoate with [60]fullerene (1) gave the corresponding aza‐[60]fullerene ester derivatives (2a‐2c, 22–35% based on the amount of [60]fullerene reacted). The nitrogen atom is bonded to the [60]fullerene cage to yield a “[5,6]‐open” type aza substructure. This was confirmed by the appearance of 30–31 sp2 signals at δC 133–147 in the carbon nuclear magnetic resonance spectra. Reaction of methyl 11‐azido‐7‐undecynoate with [60]fullerene furnished a mixture of aza‐[60]fullerene (2d, 53%) and aziridine‐[60]fullerene (2e, 38%) ester derivatives. Compound 2e was identified as the “[6,6]‐closed” type aziridine‐[60]fullerene derivative, which displayed 10 sp2 signals in the region δC 140–145 and one signal at δC 85.05 for the sp3 carbons of the cage. Refluxing a solution of compound 2d in toluene for 50 h gave about 50% yield of compound 2e, but not vice versa.