DIELS-ALDER ADDUCT OF C-60 AND 4-CARBOXY-O-QUINODIMETHANE - SYNTHESISAND CHEMICAL-TRANSFORMATIONS

The Diels-Alder reaction of o-quinodimethanes to buckminsterfullerene C-60 (1) affords thermally stable derivatives. 4-Carboxy-o-quinodimeth ane (4)was prepared in situ from 3,4-bis(bromomethyl)benzoic acid (3) and reacted with 1 to give the carboxy-substituted adduct mixture 5(n) . Due to its decreased solubility, 5(rt) was used without further puri fication for transformations into the corresponding esters and amines. This was achieved by two different methods: (a) via the carboxylic ac id chloride 6(n), whereby the alcohol/amine has to be used in excess, and (2) via the active ester 7(n = 1), which allows stoichiometric rea ctions with amines. All these derivatives are quite Soluble in commonl y used organic solvents. This enabled us to separate and completly cha racterize the products.