Fullerenoid lipids: first synthesis of structured triacylglycerols containing an Aza-[60]fullerene unit

Some 1,2- and 1,3-diacyl glycerols (with acyl groups as stearyl, oleyl, linoleyl, or stearolyl) were synthesized by conventional methods. The diacyl glycerols were esterified with 6-bromo-hexanoic acid to give the corresponding bromo-triacylglycerols (of the type AAB and ABA containing a bromo group at the distal part of the hexanoate chain). The bromo function was transformed to an azide group by reaction of the bromo-triacylglycerols with sodium azide. The resulting azido-triacylglycerols were then reacted with [60]fullerene to give the requisite aza-fullerenoid triacylglycerol of the type ABA or AAB (45-62% yield based on the amount of [60]fullerene reacted). The nitrogen atom attached to the carbon cage formed a "[5,6]open" type aza substructure, which was confirmed by the appearance of 31-32 signals in the region of deltaC 133-148 (carbon shifts of Sp2 carbons of the cage) in the 13C nuclear magnetic resonance spectra. The spectroscopic and mass spectrometric properties of these novel fullerenoid triacylglycerols are reported.