title: Synthesis of Polyglycerol, Porphyrin-Cored Dendrimers Using Click Chemistry.
abstract: Polyglycerol, porphyrin-cored dendrimers were synthesized by the click reaction of azide-cored polyglycerol dendrons and octaazidoporphyrin19. The dendrons were synthesized divergently starting with TBDPS protected allyl alcohol2. Two, three and four cycles of dihydroxylation-allyl etherification gave dendrons [G-2.5]6, [G-3.5]8, [G-4.5]11, with four, eight, and sixteen alkene groups, respectively. Dendron11was readily prepared on large scale with an overall yield of 45%. Dendron8was deprotected and converted to the corresponding alkyne - and azide-cored dendron13and15in 89% and 75% yield, respectively. Dendron11was deprotected and converted to the corresponding alkyne - and azide-cored dendron16and18in 68% and 24% yield, respectively. Both the [G-3.5]-azide15and [G-4.5]-azide18were separately "clicked" to polyalkyne core19via the Huisgen 1,3-dipolar cycloaddition to afford20and21in 65% and 66% yield, respectively. Dendrimer21has a MW ~ 16,000 and 128 peripheral alkene groups.
authors.affiliation: Department of Chemistry University of Illinois at Urbana-Champaign 600 S. Mathews Avenue, Urbana, IL 61801 (USA).
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Elmer
authors.forename: Sonny
authors.initials: S
authors.lastname: Man
authors.forename: Steven C
authors.initials: SC
authors.lastname: Zimmerman
keywords: 1,3-dipolar cycloaddition; azide; biocompatible; click chemistry; dendrimers