Synthesis of new chromogenic 2,2′-bithiazoylcalix[4]arenes

A new family of calix[4]arenes have been prepared by the incorporation of fluorescent 2,2′-bithiazole (btz) units to azocalix[4]arene. From the mono- to the tetrasubstituted btz species, five 2,2′-bithiazoylcalix[4]arenes were isolated and fully characterised. NMR analyses show that these compounds are in cone or 1,3-alternate conformations in solution at room temperature.