A,C-Bridged Calix[6]arene: Relationship between the Length of Bridge and Conformation

【Abstract】 Three new A,C-diamide bridged p-tert-butylcalix[6]arenes were synthesized from p-tert-butylcalix[6]arenes by bridging ClCH2CONH(CH2)nNHCOCH2Cl (n=3, 4, 6) in acetonitrile using K2CO3 as a base in 17%—25% yields. It was found that the bridged calix[6]arenes with shorter bridges (n=2, 3, 4 in N’,N’-bischloroacetodiamines) adopt cone conformation, but the last one (n=6) adopts alternate conformation, i.e., accompanying the lengthening of bridge, the conformation of A,C-bridged calix[6]arenes changes from cone to alternate.更多还原