180397-84-6

Upstream product

• 180397-83-5 (4-{[tert-Butoxycarbonyl-(4-hydroxymethyl-benzyl)-amino]-methyl}-benzyl)-(4-hydroxymethyl-benzyl)-carbamic acid tert-butyl ester 
• 24424-99-5 di-tert-butyl dicarbonate 
• 539-48-0 p-xylylidenediamine 
• 180397-81-3 N,N'-bis(4-carbomethoxybenzyl)-p-xylenediamine 
• 180397-80-2 C₂₆H₂₄N₂O₄ 
• 180397-82-4 N,N'-bis(tert-butoxycarbonyl)-N,N'-bis(4-carbomethoxybenzyl)-p-xylenediamine 
• 1571-08-0 methyl 4-formylbenzoate 

Downstream Products

• 180397-85-7 (4-Azidomethyl-benzyl)-(4-{[(4-azidomethyl-benzyl)-tert-butoxycarbonyl-amino]-methyl}-benzyl)-carbamic acid tert-butyl ester 
• 180397-78-8 N,N'-bis(4-azidomethylbenzyl)-p-xylylenediamine 

Relevant academic research and scientific papers

Molecular Shuttles by the Protecting Group Approach

Two new [2]rotaxane-based molecular shuttles, in which a mechanically bound dibenzo[24]crown-8 (DB24C8) macroring shunts back and forth between two dialkylammonium recognition sites situated on a chemical dumbbell, have been constructed by a novel synthetic strategy that relies upon the use of the tert-butoxycarbonyl (Boc) protecting group. During the syntheses of both molecular shuttles, this protecting group masks a dialkylammonium recognition center which is liberated only after the [2]rotaxane constitution is established. In both cases, the molecular shuttles' other dialkylammonium center is essential for the rotaxane-forming reactions and it ensures that DB24C8 is interpenetrated by threadlike precursors, as a result of noncovalent bonding interactions, to produce [2]pseudorotaxanes which are stoppered subsequently through 1,3-dipolar cycloadditions between azides and bulky acetylenedicarboxylates. The new molecular shuttles have been examined by means of dynamic 1H NMR spectroscopy, which reveals that the movements of the DB24C8 macroring are very highly dependent both on solvent properties and on the nature of the spacer unit linking the two dialkylammonium centers. Thus, DB24C8 shunts facilely between the dialkylammonium centers when the shuttles are dissolved in solvents that readily donate their nonbonding electrons into noncovalent bonds, e.g., DMF, and when spacer units that do not offer much steric resistance to shuttling, e.g., hexamethylene, are used. On the other hand, shuttling is difficult in solvents that are less inclined to donate their electrons into noncovalent bonds, e.g., (CDCl2)2, and when relatively bulky benzenoid spacer units, e.g., p-xylylene, link the two dialkylammonium centers. It has been proposed that the DB24C8 might act as a "ferry" which carries a proton between dialkylammonium and dialkylamine moieties in a singly protonated [2]rotaxane by means of ion-dipole interactions.

Self-Assembling - and Rotaxanes from Secondary Dialkylammonium Salts and Crown Ethers

The self-assembly of three new rotaxanes - two rotaxanes and a rotaxane - formed by a "threading followed by stoppering" approach is described.These template-directed syntheses rely on the formation of pseudorotaxane intermediates, which self-assemble in solution from functionalized secondary dialkylammonium hexafluorophosphate threads and macrocyclic polyether rings (either dibenzocrown-8 or its asymmetric constitutional isomer).The stoppers - substituted 1,2,3-triazoles - were created by thermally allowed 1,3-dipolar cycloaddition between azido groups, which terminate the threads, and di-tert-butyl acetylenedicarboxylate. - Keywords: interlocking molecules; molecular recognition; pseudorotaxanes; rotaxanes; template syntheses