Resin properties solid support chemistry

While considerable efforts have been spent in the past few years in the field of solid supports for combinatorial chemistry [73], most of them were devoted to modified polystyrenic beads with different sizes, loadings or swelling properties [74], or carrying different functionalities or linkers for library synthesis [75], or to solid supports different from resin beads (pins [76], cellulose [77], soluble supports [78], and so on). Few reports dealt with labelled solid supports prepared by chemical reactions (see the previous paragraphs) and significant efforts in the field of material sciences to obtain intrinsically labeled, nonchemically encoded, easily readable, combinatorial solid supports have not been reported. 

Nevertheless, there are some problems correlated with the use of this support, such as its voluminous nature when swollen, its lack of physical stability im-der harsh handling conditions, and its incompatibility with a number of solvents (8). For this reason, several groups of researchers have investigated a number of alternative solid supports, for solid-phase chemistry, in order to improve resin properties, such as physical robustness, ease of handling, enhancement in loading,... 

Resins. The solid-phase support (Resin, Fig. 1) is a well-solvated polymeric matrix in which the peptide chains are attached throughout a resin bead. The polymeric backbone is a flexible superstructure through which reagents and solvents can easily flow and once swollen has the physical properties of a gel (144,145). This is in contrast to the common perception that solid-phase chemistry only occurs on the surface of each poljnner bead. Because of the permeable nature of the polymers, reaction rates approach but are slightly slower than that found in solution. Commercially available poljnners have functional group loadings typically in the 0.2-1.0 mmol/g range. As an example of the distribution... 

A key element of solid-phase-assisted chemistry, which has been underscored by most chemists, is the support itself However, it is evident from the discussion so far that the supports used are still far from ideal in several respects and that there is considerable scope to prepare improved supports [8]. Indeed, this has become a very active interdisciplinary area of research. Many reviews have been devoted to the various supports employed in solid-phase-assisted synthesis [9, 10] together with some reviews devoted to the physical properties of resins [11]. 

In triphase catalysis, solvated resin supports are important carriers for solid-phase organic synthesis in combinatorial chemistry. The physical properties of resin, resin swelling, dynamic solvation, and solvated supports are important factors in affecting the synthesis. However, these factors are also affected by solvent. Selective solvation of resin alters the local reactivity and accessibility of the bound substrate and the mobility of the entrapped re-... 

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