Rapid synthesis of dendrimers based on calix[4]resorcinarenes

Abstract

Calix[4]resorcinarenes are phenolic macrocyclic compounds, and readily available from resorcinols and aldehydes. We were interested in calix[4]resorcinarenes as highly functionalized core molecules for the rapid synthesis of dendrimers because of their ease of synthesis and because they are less affected by steric constraints. Calix[4]resorcinarenes having 16 1 and 12 2 reactive hydroxy groups, respectively, were prepared as polyfunctional core molecules. The second-generation dendrimers were synthesized by the divergent method. The first-generation dendrimer 6 was obtained by etherification of 1 with 3,5-bis(allyloxy)benzyl bromide 5. After the deallylation of 6, etherification with 5 afforded the second-generation dendrimer 8. Dendrimers were characterized by ¹H- and ¹³C-NMR, MALDI-TOF mass spectrometry and GPC. The molecular weight of second-generation dendrimers obtained from these calix[4]resorcinarenes and 5 reached 9345 and 7171, respectively.