Proton Sponges with Other Aromatic Backbones

2 Proton Sponges with Other Aromatic Backbones 

After the discovery of OMAN (1), the search started for other, more basic proton sponges possessing aromatic backbones with optimal, even shorter N... N distances to form N H+... N bridges with the optimal linear geometry. Staab has found that fluorene series 

Incorporation of a dialkylamino group of proton sponge into an aromatic ring such as in quino[7.8-h]quinoline (18) results in an increase in basicity [18,19]. In contrast to 

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