Adding upper rim functionality to the calixarenes

Nicolis, N. Douteau-Geuvel, F. Villain, A. Thomas and C. de Rango, Chem. Commun., 2000, 161. 

Aluminium trichloride [CORROSIVE REACTS VIOLENTLY WITH WATER] 

Calcium chloride guard tube Inert atmosphere line Rotary evaporator Glassware for work-up 

Note Work in a fume hood as an unmistakable odour of benzene appears following treatment with aluminium trichloride. 

Suspend 4-f-butylcalix[4]arene (1.5 g, 2.0 mmol) and phenol (0.28 g, 3.0 mmol) in toluene (30 mL) in a two-necked round-bottomed flask (125 mL) with an inlet providing a flux of inert gas and an outlet fitted with a calcium chloride guard tube. Add anhydrous aluminium trichloride (1.5 g, 11 mmol), which clarifies the suspension slightly, and stir for 4h. During this time the mixture turns from colourless to yellow then orange. A red oil may be observed to separate. After 4 h, add hydrochloric acid (65 mL of a 1m aqueous solution) and continue to stir vigorously for a further 1 h. Ensure that all the sticky red oil is removed from the sides of the vessel and is stirred into the biphasic solution. It may be necessary to use a spatula to free this material. The upper aromatic layer will turn yellow and solids will precipitate out within it. Once all the oil has been stirred to yield a powdery product, leave the mixture to settle for 20 min. Separate the upper organic 

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