Patent ID: 7572948

Claim:
A method of isolating a fulvene from a composition comprising the fulvene and at least one cyclopentadiene-containing impurity, comprising: a) contacting the composition with 4-(N,N-dimethylamino)benzaldehyde, pyrrolidine, and optionally a first solvent to provide a first mixture; b) contacting the first mixture with an aqueous acid to provide a second mixture; c) extracting the second mixture with a second solvent to provide an extract, optionally concentrating the extract, and optionally drying the extract; and d) isolating the fulvene from the extract by chromatography; wherein: the fulvene has the formula R 1 , R 2 , and R 3 , in each occurrence, are independently a hydrocarbyl group having up to 20 carbon atoms, or hydrogen.