Designing poly(amido amine) dendrimers containing core diversities by click chemistry of the propargyl focal point poly(amido amine) dendrons

General, fast, efficient, and inexpensive methods for the synthesis of poly (amido amine) (PAMAM) dendrimers having core diversities were elaborated. In all syntheses, the major step involved an inexpensive 1,3-dipolar cycloaddition reaction between an alkyne and an azide in the presence of Cu(I) species, which is known as the best example of click chemistry. The propargyl-functionalized PAMAM dendrons are obtained by the divergent approach using propargylamine as an alkyne-focal point. Three core building blocks, 1,3,5-tris(azidomethyl)benzene, N,N,N',N'-tetra(azidopropylamidoethyl)-1,2-diaminoethane, and 4,4'-(3,5-bis(azidopropyloxy)benzyloxy)bisphenyl, were designed and synthesized to serve as the azide functionalities for dendrimer growth via click reactions with the alkyne-dendrons. These three building blocks were employed together with the propargyl-functionalized PAMAM dendrons in a convergent strategy to synthesize three kinds of PAMAM dendrimers with different core units. This novel and pivotal strategy using an efficient click methodology provides the fast and efficient synthesis of the PAMAM dendrimers with the tailed made core units. (c) 2007 Wiley Periodicals, Inc.