Abstract
The synthesis of chromogenic mono acid-type azocalix[4]arene derivatives is described in this study. From p-tert-butylcalix[4]arene, which was made with p-tert-butylphenol as a starting material, a new family of azocalix[4]arene monocarboxylic acid derivatives (5a-d) were synthesized. Four azocalix[4]arenes (3a-d) were produced by attaching 4-methoxy-, 4-ethyl-, 4-chloro-, and 4-bromoaniline to 25,26,27,28-tetrahydroxycalix[4]arene through a diazo-coupling reaction. To obtain partial cone conformation acid derivatives, their mono ester units were synthesized with ethyl bromoacetate and hydrolyzed in a basic media (5a-d). Products were obtained in suitable (79-92 %) yields, with 25-(carboxymethoxy)-26,27,28-trihydroxy-5,11,17,23-tetra(4-methoxyphenyl)azocalix[4]arene (5a) being the product with the highest yield (92 %). FT-IR and 1H-NMR spectroscopy approaches, as well as elemental analysis techniques, were used to elucidated the synthesized products.
