Solid phase synthesis of aryl-ether dendrimers

Abstract

Solid phase chemistry can be used to prepare, in excellent yield and purity, a range of Fréchet-type aryl-ether dendrimers, for use in either dendrimer conjugation studies, resin loading enhancement or the wedge based synthesis of larger dendrimers.

Dendritic supports in organic synthesis

“…of pharmaceutical interest Basso et al, 2000b . As an alternative to the PAMAM dendrons, the use of 'inverted' Frechet-type dendrons was alsó Ž . explored Basso et al, 2001 . Starting from either a glycine᎐Rink-modified polystyrene resin or from a hydroxymethylpolystyrene resin, several genera-Ž .…”

Dendrons and dendritic catalysts immobilized on solid support: Synthesis and dendritic effects in catalysis

“…The increase depends on the nature of the dendron and the polymeric core and ranges between 6 and 25% (Table 1). 25(b), 42,43 For beads with a diameter of approximately 100 m, this increase greatly exceeds that which may be expected from the addition of a thin dendritic layer. Thus, we may assume that, as Bradley 38(a) suggested, the dendrons, gradually filling the pores of the microporous resin, try to position themselves as far apart as possible, and this weakens the interaction between the polymer chains, separates them, and inflates the bead.…”

“…Indeed, Fréchet-type polyether dendrimers prepared in solution have a broad spectrum of chemical and coordinative compatibilities. 41 Accordingly, poly- ether dendron synthesis on solid supports was targeted and reported, initially by Bradley et al 42 and later by our group. 43 Instead of the 3,5-dihydroxy benzyl alcohol derivatives used in Fréchet-type dendrimers, prepared in solution, a more SPOS-suitable 3,5-bis(hydroxymethyl) phenol unit was conceived as a building block for dendron construction.…”

“…Using this building block, Bradley et al 42 constructed the dendrons up to the fourth generation through two repetitive steps (Scheme 7). An alternative synthetic strategy enabled us to prepare the dendron, again via two repetitive steps, with the dimethyl-5-hydroxyisophthalate itself, without any need for building block preparation in solution (Scheme 8).…”

“…The dendritic structure was based Scheme 7. Synthesis of polyether dendrons by Bradley et al 42 The reagents and conditions are as follows: (i) DIAD, PPh 3 , and tetrahydrofuran and (ii) Bu 4 NOH (aqueous)/tetrahydrofuran (1:3).…”