Polydimethylacrylamide

Another important consideration was the choice of resin. The use of Hmb was developed using resins composed of polydimethylacrylamide polymerized within the pores of a solid, macroporous support, either Pepsyn or polyhipe, both are exemplified below. The use of Hmb involves the switching of solvents from DMF to dichloromethane the resins mentioned have excellent swelling properties in both solvents. However, some commercial polystyrene supports have given poor results because of the need to switch solvents, which can cause problems due to resin shrinkage. 1 ... 

Methoxycarbonyl-functionalized polydimethylacrylamide resin was chosen as the solid support. It was converted into a primary amine by treating it with ethylenediamine. An internal reference-spacer amino acid was incorporated by coup-ing with A -Fmoc-norleucine anhydride and the cleavage of the A -Fmoc group with 20% piperidine, followed by the addition of the reversible-linkage agent [2,4,5-trichlorophenyl 4-(hydroxymethyl)benzoate] in the presence of HOBt. 

However, the best results were obtained when the first nucleoside was attached via the succinyl linker onto the ethylenediamine-treated polydimethylacrylamide resin (Figure 19.4) [178,179] or Enzacryl Gel K-2 [177]. The polydimethylacrylamide support has been utilized by Gait et al. [180] in the automated solid phase oligonucleotide synthesis by the phosphotriester method on a peptide synthesizer. 

A solid-phase equivalent of the Narang s safety catch thioether convertible into sulfoxide group [256a], 2-(4-carboxyphenylthio)ethanol (Carnet), has been proposed by Felder et al. [262] for use with the phosphotriester chemistry on a polydimethylacrylamide support (Figure 19.10). The synthesis was conducted on... 

Polystyrene and polydimethylacrylamide gels are not sufficiently stable for the mechanical wear of continuous-flow pressure. To alleviate this problem, composites have been constructed in which a rigid matrix supports the soft... 

JT Sparrow, NG Knieb-Cordonier, NU Obeyesekere, JS McMurray. A large pore polydimethylacrylamide resin for solid-phase peptide synthesis Applications in FMOC chemistry. Peptide Res 9 297-304, 1996. 

The methodology of solid phase peptide synthesis (SPPS) [65, 66] has been credited with the award of 1984 Nobel Prize in chemistry [67] to its inventor, Bruce R. Merrifield of the Rockefeller University. At the heart of the SPPS lies an insoluble polymer support or gel , which renders the synthetic peptide intermediates insoluble, and hence readily separable from excess reagents and by-products. In addition to peptide synthesis, beaded polymer gels are also being studied for a number of other synthetic and catalytic reactions [2]. Ideally, the polymer support should be chemically inert and not interfere with the chemistry under investigation. The provision of chemical inertiKss presents no difficulty, but the backbone structure of the polymer may profoundly influence the course of the reaction on the polymer support. This topic has attracted considerable interest, particularly in relation to the properties of polystyrene (nonpolar, hydrophobic), polydimethylacrylamide (polar, hydrophilic), and copoIy(styrene-dimethylaciylamide) (polar-nonpolar, amphiphilic) (see later). 

For details of polystyrene and polyDMA (polydimethylacrylamide) see Refs. [7, 12] respectively. Copoly(DMA-styrene) was obtained from the activated copolymer sampte 8c (see Table 6) TOL=toluene, EAC=ethyl acetate, THF=trtrahydrofuran, DCM=dichloromethane, DMF =dimethylformamide, DMSO=dimethylsulfo3dde, MeOH=methanoJ, AcOH = acetic acid Polymers with higher, or lower, expanded volumes can be obtained readily for all three polymer types [7, 12], but the pattern of polymer swelling in different solvents is a consequence of the chemical structure of the polymer... 

Polycyclocondensation, high-temperature catalytic 142, 146, 148-162 Polydimethylacrylamide 19 Polyelectrolytes, water-soluble 49 Polyethylene glycol nonyl phenol 58 Polyheteroarylenes 158, 162, 167 Polynaphthoylenebenzimidazoles 118,146-165... 

Three conunercial capillary-based DNA sequencers introduced Sequencing with low-viscosity polydimethylacrylamide performed using noncovalent capillary coating... 

A gel matrix based upon the use of polydimethylacrylamide (PDMA) has also enjoyed great commercial success [76,77]. Developed by Madabhushi and coworkers at Perkin Elmer Corporation (now Applera Corporation) and used in their family of high-throughput DNA sequencers, PDMA... 

Improved CE-based methods to measure kinase activation in single cells have been described recentiy. Phosphorylated and nonphosphorylated forms of peptide substrates for protein kinase C and calcium-calmodulin activated kinase were separated by CZE using a polydimethylacrylamide (PDMA) coated capillary and buffers containing different concentrations of betaine (0-1 M). The separation system is compatible with a living cell and, therefore, adaptable to the laser micropipet system, a strategy to measure the activation of enzymes in single mammalian cells. 

Finally, the styrene-divinylbenzene copolymer is certainly not the only starting material suitable for functionalization. Impermeable polymers were grafted and porous glass beads coated with organic polymers for derivatization, but these pioneering efforts had few followers so far. More auspicious seems to be, at this time, the application of polyamides, such as polyacrylamide, poly-dimethylacrylamide or polydimethylacrylamide-co-Boc-j -alanylacroyl-hexa-methylenediamine. Their promise stems from the compatibiUty of the support with the peptide chain. 

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