Oxidation of 3-alkyl-substituted 2-pyrazolino[60]fullerenes: a new formyl-containing building block for fullerene chemistry.

: A new building block for fullerene chemistry, endowed with a formyl group on C-3 of the 2-pyrazoline ring, has been prepared in a simple two-step synthesis by oxidation of readily available 3-alkyl-substituted 2-pyrazolino[60]fullerenes; the new building block paves the way for the preparation of new light-harvesting fullerenes.