Synthesis of an Adamantane-based Tetralactam and its Complexation with Dicarboxamides

Tetralactam macrocycles are suitable candidates to be employed as synthetic receptors for charged or neutral guests. In the sensing of neutral molecules non polar solvents such as chloroform or dichloromethane are usually employed since the hydrogen-bonded interactions can be established. Thus one of its main limitations of the studied macrocycles is their low solubility in these solvents.

Herein we describe the synthesis of an adamantane-based tetralactam macrocycle which is partially soluble in chlorinated solvents. For this purpose, by following a clipping methodology, we firstly synthesized a kinetically stable pseudorotaxane having a removable tetraalkylfumaramide thread and the desired macrocycle. A subsequent thermal dethreading straightforwardly yielded the adamantane-based macrocycle. Afterwards the affinity of the adamantane-derived macrocycle for a series of symmetric and non-symmetric fumaramides and succinamides guests was studied, calculating the association constants when the corresponding [2]pseudorotaxanes are assembled.