Synthesis of p-tert-butylthiacalix[n]arenes (n=4, 6, and 8) from a sulfur-bridged acyclic dimer of p-tert-butylphenol

The one-step method for the synthesis of p-tert-butylthiacalix[n]arenes TCnAs (n=4 and 6) by reacting p-tert-butylphenol 1 with elemental sulfur in the presence of a base was advantageously replaced by a two-step procedure in which a sulfur-bridged linear dimer of 1 was prepared first to use as the starting material for the cyclo-condensation with sulfur to greatly improve the yields of TC4A (83%) and TC6A (5.3%). The present dimer method allowed the isolation of TC8A in an appreciable amount (4.3%) for the first time.