Facile synthesis of calix[4]arenes in ABAC type upper rim substitution
作者:Kwanghyun No、Jong Eun Kim、Kyoung Mee Kwon
DOI:10.1016/0040-4039(95)01820-8
日期:1995.11
Calix[4]arenes with three different substituents in ABAC pattern at the upper rim of calix are synthesized by '3 + 1' fragmentation condensation reaction between trimer of p-substitutedphenol (ABA) and 2.6-bishydroxymethylated p-substitutedphenol (C).
Facile Synthesis of Calix[5]arenes with Three Different Upper Rim Substituents
作者:Kwanghyun No、Kyoung Mee Kwon
DOI:10.1055/s-1996-4391
日期:1996.11
Four calix[5]arenes, which have three different substituents at the upper rim of calix, are synthesized by the ‘3+2’ fragmentation condensation reaction. An equimolar mixture of p-substituted phenol trimer (BCB) and 2,2’-bishydroxymethyl p-substituted phenol dimer (AA) was refluxed for 3.5 days in xylene to produce calix[5]arenes 5a-d in 27-32% isolated yield. The structure of the calix[5]arenes was established by elemental analysis and 1H NMR/13C NMR spectroscopy.
concave molecules interesting building blocks for the synthesis of more sophisticated molecular architectures. Seven OH-free and O-permethylated monofunctionalized calix[5]arenes carrying either additional methyl or tert-butyl groups are prepared following fragment condensation protocols. This strategy proves to be superior to previous approaches. Calix[5]arenes with free OH groups all adopt a cone conformation