PROCEDURES FOR THE SELECTIVE ALKYLATION OF CALIX[6]ARENES AT THE LOWER RIM

New partially alkylated calix[6]arenes have been synthesized. Dependin g on the conditions, mono-, 1,2-di-, 1,3-di, 1,2,3-tri-, 1,3,5-tri-, 1 ,2,4,5-tetra-, and 1,2,3,4,5-pentamethylated derivatives of p-tert-but ylcalix[6]arene could be obtained in moderate to good yields. Methylat ion or benzylation of the parent calix[6]arene showed a regioselectivi ty towards 1,2-di-, and 1,2,3-trisubstitution. The solid state structu re of 1,2,4,5-tetrasubstituted p-tert-butylcalix[6]arene [R=O(CH2CH2O) 2CH3] has been elucidated by X-ray analysis.