Calix[4]arene‐tetranitrone as crosslinker in dental composite materials

The synthesis of a functionalized calix4]arene bearing 1,3‐dipolaric nitrone groups ( 5 ) has been carried out. The reaction of N‐methylhydroxylamine or N‐propylhydroxylamine with the carbonyl group of 5,11,7,23‐tetraformyl‐25,26,27,28‐tetraalkoxycalix4]arene leads to calix4]arenes bearing a nitrone function at each of the four para‐positions. Via 1,3‐dipolar cyclo‐addition of acrylic acid methyl ester with the nitrone functions of 5 , subsequently an upper rim‐substituted tetraisoxalidinecalix4]arene is quantitatively synthesized. Further, the minimization of shrinkage of a dental filling depending on the amount of calix4]arene‐tetranitrone is discussed. Copyright © 2011 Society of Chemical Industry