Syntheses of Acyclic and Macrocyclic Compounds Derived from 9,9‐Diethylfluorene (Part I)

A series of new 9,9‐diethylfluorenes consisting of three side‐arms each bearing a heterocyclic, bis(carboxymethyl)amino, bis(carbamoylmethyl)amino, bis(ethoxycarbonylmethyl)amino or an amino group were prepared on the basis of 2,4,7‐tris(bromomethyl)‐9,9‐diethylfluorene. Imidazolyl, benzimidazolyl, pyrazolyl, pyrrolyl, 1,3‐dioxoisoindolyl and pyridinium groups were taken into account as heterocyclic units, attached to the aromatic skeleton via −CH(2)−, −CH(2)NHCH(2)− or −CH(2)N=CH− linkers. In addition to the seventeen 2,4,7‐trisubstituted 9,9‐diethylfluorenes, two macrocyclic compounds were prepared on the basis of 2,7‐bis(aminomethyl)‐9,9‐diethylfluorene. The excellent yield of the macrocyclization reaction is worth a special mention. Both the acyclic and the macrocyclic fluorene‐based compounds have, among other things, the potential to act as artificial receptors for different substrates in analogy to the known receptors consisting of a benzene or biphenyl core.