Oligoamides

Figure 9.6 Oligoamide strands 10, 10, 11, and 12 containing two quadmply H bonding units linked in a head-to-head fashion. Control strand 12 is essentially half of 12.

Hua FJ, Yang XW, Gong B, Ruckenstein E. Preparation of oligoamide-ended polyfethylene glycol) and hydrogen-bonding-assisted formation of aggregates and nanoscale fibers. J Polym Sci Part A Polym Chem 2005 43 1119-1128. 

Table 16.2. Synthetic amino acids or precursors thereof suitable for the solid-phase preparation of oligoamides.

One type of oligoamide that can readily be prepared on supports without the need for any partially protected monomers (which are often tedious and expensive to synthesize) are N-substituted oligoglycines (Figure 16.21). These compounds are prepared by a sequence of acylation of a support-bound amine with bromoacetic acid, displacement of the bromide with a primary aliphatic or aromatic amine, and repeated acylation with bromoacetic acid. Because primary amines are cheap and available in large number, this approach enables the cost-efficient production of large, diverse compound libraries. Alternatively, protected N-substituted glycines can also be prepared in solution and then assembled on insoluble supports (Entry 5, Table 16.2). 

Preparation of mono-adducts of fullerene - for studies on electrostatic interactions - was undertaken by cyclopropanation of fullerene with appropriately functionalised malonic esters 1 (Bingel reaction) to form 2. Coupling with the tert-butyl protected oligoamide-amino-dendron 3 and subsequent hydrolysis lead to the water-soluble fullerene dendron 5, which can carry up to nine negative charges after depro to nation. After association with the zinc complex of cytochrome C, photoinduced electron transfer (PET) from the redox protein to the fullerene can be accomplished, which was studied by fluorescence spectroscopy. 

D. A. Smith and S. Vijayakumar, Tetrahedron Lett., 32, 3617 (1991). Molecular Modeling of Intramolecular Hydrogen Bonding in Simple Oligoamides. 2. GB/SA CH2CI2. 

Polycondensations of aminoacids and oligoamids have led only to successive pol5mierization and crystallization with a loss of the initial orientation. A seeming exception, the poljonerization of e-aminocaproic acid from the solid state which produced oriented pol5mier crystals was shown to be an epitactic pol5nnerization and crystallization (75). Some of the reactions were topochemical since they followed a reaction path only possible from the crystalline monomer, but none of the investigated cases demonstrated a solid state path from the monomer to the polymer crystal. 

Gong has recently described a class of oligoamides that employ quadruple hydrogen bonding to form solid-state homodimers (Fig. 7).18 The monomers were derived from 3-aminobenzoic acid, 1,3-benzenedicarboxylic acid, and 1,3-diamino-benzene and, similar to Meijer s group, formed via DADA and DDAA sequences. In contrast to Meijer and colleagues, however, the donor and acceptor units were separated within the monomers such that secondary interactions were less prevalent... 

Heteroaromatic oligoamides with dDNA affinity 03EJO3473. 

The formed oligoamides have a defined molecular weight and show a narrow molecular weight distribution in dependence on the amount of added degradation compound. The molecular weight distribution with demonstrates the... 

Fig. 3 Ti,ed-3/n - relation of oligoamide 6 (controlled degradation by TMAn). t]red in o-dichlorobenzene/o-cresol, c = 0.2 gdl lab series lab reaction in a stirred glass vessel extrusion series reactive extrusion in a twin-screw extruder (ZSK 28, Werner Pfleiderer) [5]...

On the basis of the results of the solution viscosity and the calculated molecular weights the following relation was established for poly-/oligoamide 6 ... 

The stability of the molecular weight of the degraded oligoamide 6 is shown by post-condensation tests (Table 1). The base material was extmded once to examine comparable products. The molecular weight of this PA-6 increases in... 

Table 1 Thermal post-condensation treatment of polyamide 6 and oligoamide 6 products...

Table 5 Controlled degraded polyamide 6 by TMAn and an oligoamide 6...

These new PTFE-PA materials can be processed without any problems on commercial processing equipment like twin-screw extruders and injectionmoulding machines. The specific adjustment of the melt viscosity could be realised through additives (lowering of MFI additive [10,18] increase of MFI acid-terminated oligoamides [9,10]). The new materials combine the good material properties of PTFE and polyamide with the processability of polyamide and are particularly well-suited for wear-resistant maintenance-free bearings. 

Ernst, J. T., Becerril, J., Park, H. S., Yin, H., and Hamilton, A. D. (2003) Design and application of an alpha-helix-mimetic scaffold based on an oligoamide-foldamer strategy Antagonism of the Bak BH3/Bcl-xL complex. Angew. Chem. Int. Ed. Engl. 42, 535-539. 

Oligoamide-, terephthalamide-, oligourea- and biphenyldicarboxamide-based a-helical mimetics Bcl-X[/Bak interaction inhibition Mimetics could successfully displace the BH3 domain of the Bak peptide from the Bcl-X[/Bak BH3 complex, with K, values in the low micromolar range [98, 99]... 

Backbone-Rigidified Folding Oligoamides with Tunable Cavity Sizes. .. 3... 

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