Polyacrylamide resin

A typical process for the preparation of a poly(methyl methacrylate) suspension polymer involves charging a mixture of 24.64 parts of methyl methacrylate and 0.25 parts of benzoyl peroxide to a rapidly stirred, 30°C solution of 0.42 parts of disodium phosphate, 0.02 parts of monosodium phosphate, and 0.74 parts of Cyanomer A-370 (polyacrylamide resin) in 73.93 parts of distilled water. The reaction mixture is heated under nitrogen to 75°C and is maintained at this temperature for three hours. After being cooled to room temperature, the polymer beads are isolated by filtration, washed, and dried (69). 

Atherton, E. and Sheppard, R.C. (1989) Solid Phase Peptide Synthesis, a Practical Approach. 203pp. IPR Press, UK. A working handbook focussing on polyacrylamide resins and Fmoc-chemistry. 

One of the very first papers reporting about endo-linkers was published by Elmore et al. (Scheme 10.4) [13]. They described a new linker containing a phos-phodiester group (19) for solid-phase peptide synthesis using a Pepsyn K (polyacrylamide) resin. After completion of coupling and deprotection cycles, the phos-phodiester (20) was cleaved with a phosphodiesterase. In this way / -casomorphin. Leu-enkephalin and a collagenase substrate (21) were synthesized in high yields. 

New polymeric solid supports have been devised, which include macroporous styrene-divinylbenzene containing large fixed pores, porous glass beads, insoluble carbohydrate polymers, poly(ethylene oxide), cross-linked derivatives of polyacrylamide resins, and graft copolymers of polystyrene and poly(ethylene oxide). The last two have been the most effective and widely used and have competed well with the original copoly(styrene-divi-nylbenzene) beads. 

POLYACRYLAMIDE RESINS, MODIFIED see MRA075 POLYAETHYLEN see PJS750... 

From their chemical architectures the gel-type resins can be classified as belonging to one of two different types of solid supports. For hghtly crosshnked polystyrene and polyacrylamide resins the reactive sites are located along the polymer chains in a statistical manner. Reaction kinetics can be expected that are sinnilar to those associated with a soluble polystyrene that was proposed by Shemiakin et al.f l for peptide synthesis. However, reaction rates were found to depend on the location of the reactive sites on such linear noncrosslinked polystyrenes. In fact, reactive sites located on a flexible polymer loop should exhibit a different kinetic behavior to those close to a more rigid, crosshnked section. 

Scheme 7.14. Solid-phase synthesis on polyacrylamide resin.

Another technique for the purification of monoterpene glycosides utilizing gel permeation and hydrophobic-interaction chromatography on polyacrylamide resin has recently been published (49). This gentle yet highly selective procedure for purification was applied on a micro-scale to model monosaccharides of eight monoterpene aglycons. 

These resins have their roots in the polyacrylamide resins introduced in the 1980s for SPPS using the fluorenylmethoxycarbonyl (Fmoc)-tert-butyl (tBu) strategy. They were developed following the concept that the insoluble support and peptide backbone should have comparable polarities [44]. 

However, the polyacrylamide resin beads are compressible and thus more suitable for batch-wise rather than continuous-flow solid phase synthesis. To make the support withstand pressure and thus perform well under continuous-flow... 

The first polyacrylamide resins were synthesised by copolymerisation of /V,N-dimethylacrylamide 1 (basic monomer), ethylenebisacrylamide 2 (crosslinking agent) and N-acryloyl-N -(tert-butoxycarbonyl-P-alanyl)hexamethylene diamine 3 (functionalised monomer)H as shown in Scheme 1.5.5.1. 

The early anionic polyacrylamide resins are still widely used, both in powder and liquid form. The natural anionic charge on cellulose fibres, and the contaminants commonly found in papermaking systems, led researchers to seek methods of putting a cationic charge on these chemicals, thus making them more substantive to fibres. 

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