A new approach to cap 1, 3, 5-trimethyloxy-p-tert-butyl calix [6] arene with 1, 1, 1-tri ( tosyloxyethoxyethoxymethyl) propane to form a pair of separable stabilized in-and out-calix [6] cryptands was reported. After heating 5a or 5b at 280° C, the interconversion between them was not detected by TLC, which provides a direct and non-spectral methodology to obtain unambiguous evidence for the ring immobilization in calix [6] arenes with ...