Chemoselective Building Blocks for Dendrimers from Relative Reactivity Data

Abstract

Competition reactions for the substitution of monochlorotriazines with different amines provide relative reactivity data that can be used to identify new groups for the chemoselective syntheses of dendrimers based on melamine. Target 1 is prepared using a one-pot per generation strategy without protecting group manipulations or functional group interconversions.

Identification of diamine linkers with differing reactivity and their application in the synthesis of melamine dendrimers

“…That is, during a convergent synthesis, protecting group manipulations and functional group interconversions could be avoided because the benzylic amine would react preferentially (essentially exclusively) with the monochlorotriazine dendron being elaborated. 1,[3][4][5][6][7] The low stability of these aniline derivatives required reasonable, but additional, care on handling. While the use of distilled solvents and inert atmospheres are not uncommon, nor is the requirement for refrigerated storage of intermediates, we recognized that these precautions could impact the broader acceptance of these materials.…”

“…1,2 Our early targets commonly incorporated p-aminobenzylamine because of the significant differences in the reactivity of the amines of this group. That is, during a convergent synthesis, protecting group manipulations and functional group interconversions could be avoided because the benzylic amine would react preferentially (essentially exclusively) with the monochlorotriazine dendron being elaborated.…”

“…1 From these studies, aminomethylpiperidine emerged as a diamine linker of choice and was used extensively. 1,2,7,9,[15][16][17]19,20 Using competition experiments, the relative reactivity difference measured for the cyclic secondary amine and primary amine of aminomethylpiperidine is ~ 20 times. Theoretically, 5% of the product formed might derive from reaction of the monochlorotriazine dendron with the primary amine instead of the desired secondary amine.…”

New APTES Cross-Linked Polymers from Poly(ethylene oxide)s and Cyanuric Chloride for Lithium Batteries

“…[10][11][12] They also demonstrated the chemoselective reactivity of the three reactive sites on cyanuric chloride at various temperatures. Reaction of one site takes place at 0°C, the second site at room temperature, and the third site above 70°C.…”

Dendrimers based on [1,3,5]‐triazines

“…35,36 The strategy expanded the use of chemoselective diamines from p-aminobenzyl amine to additional diamines. Diamines comprising amines with reactivity differences greater than 20 were found to be useful for chemoselective reactions.…”