4-tert-Butylcalix[4]arene

White to light beige crystalline powder or flakes

It is used as a starting material for further derivatization, including halogenation, acylation, and diazo coupling.

The calixarene recrystallises from CHCl3 in large solvated prisms (m 380o dec); it effloresces on drying in air. Its tetra-acetate crystallises from Ac2O in colourless prisms m 332-333o(dec). It crystallises from CCl4 or chlorobenzene /EtOH (m >300o) and the tetra-acetate crystallises from CHCl3/EtOH m >290o(dec). It also crystallises from toluene in white plates with toluene of crystallisation m 344-346o (330-332o); the tetra-acetate crystallises with 1AcOH of crystallisation m 383-386o (softening at 330-340o, also m 283-286o), but acetylation with Ac2O/NaOAc gives the triacetate which recrystallises from AcOH with 1AcOH of crystallisation m 278-281o. 4-tert-Butylcalix[4]arene (100mg) is unchanged after boiling for 4hours with 10N KOH (0.04mL) in xylene (4mL). [Br J Pharmacol 10 73 1955, K.mmerer et al. Monatsh Chem 109 767 1978, Gutsche et al. J Am Chem Soc 103 3782 1981; see also Kluawer in Calixarenes, Vicens & B.hner eds Academic Press 1991, Beilstein 6 IV 7858.]