Resins functionalization

Polystyrene, PEG-PS, and PEGA-based resins pre-functionalized with all the standard linkers required for the production of peptide adds, peptides amides, and protected peptide fragments are commerdally available. 

The functionalization of commercially available standard solid supports is of particular interest for combinatorial purposes to enable a broad range of reactions to be studied. Because these transformations usually require long reaction times under conventional thermal conditions, it tvas obvious to combine microwave chemistry with the art of resin functionalization. 

In a related study the same authors investigated the effect of microwave irradiation on carbodiimide-mediated esterification of benzoic acid on a solid support [24]. The carboxylic acid was activated with N,N -diisopropylcarbodiimide (DIG) via the O-acyl isourea or the symmetrical anhydride procedure. The isourea proce- 

An interesting attempt at resin functionalization, microwave-assisted PEGylation of Merrifield resin, has been described [26]. Treating commercially available polystyrene Merrifield resin with poly(ethylene glycol) (PEG 200) at 170 °C for only 2 min afforded the corresponding hybrid polymer combining the advantages of 

Interesting work on the synthesis of resin-bound naphthoquinones has recently been reported [32]. Resin-bound amines form intensely colored beads when treated with 2,3-dichloro-5-nitro-l,4-naphthoquinone this can be used as a qualitative test 

Very recently an efficient synthesis of novel photocleavable linkers has been described [33]. Commercially available PEG 4000 was modified by standard esterifica- 

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A new solid phase method to synthesize libraries of compounds based on 1,2,5-thiadiazolidine heterocycle was developed (00TL(41)3161). Starting from the coupling of the protected aminoacid to the resine functionalized with p-alkoxybenzylalcohol as the linker, a series of sulfahydantoins 251 could be obtained. The method is applicable to aminoacids with a basic side chain, aliphatic aldehydes or aldehydes with basic functionalities. 

Scheme 7.8 Resin functionalization with carboxylic acids using (a) Merrifield resin and (b) chlorinated Wang resin as the polymer support.

An interesting approach to resin functionalization has been presented by the group of Yaylayan, who described microwave-assisted PEGylation of Merrifield... 

Suzuki, T. M., Tanaka, D. A. P., Tanco, M. A. L., Kanesato, M., H., Yokoyama, T., Adsorption and removal of oxo-anions of arsenic and selenium on zirconium(IV) loaded polymer resin functionalized with diethylenetriamine-N, N,N ,N -polyacetic acid, J. Environ. Monit., 2, 2000, 550-555. 

Resins with a DVB content of less than 8 wt.% are of the gel-type without permanent porosity. Such resins function only in the presence of polar components that swell the resin structure. Resins with a DVB content of 12 wt.% or more have permanent macroporosity. These materials also have a microporous gel phase consisting of gel-type microspheres [25],... 

Most importantly the procedure is a facile one-pot method. The branching in this instance is an integral part of the resin architecture and a large proportion of chain ends is provided without resort to decorating an existing conventional resin. Functional analogues of these seem likely to form the basis of supported species with improved mass transfer characteristics. 

Aiming at easier workup conditions, immobilization of several transition metal catalysts, which show activity for the epoxidation of allylic alcohols, on polymer support has been investigated. For example, Suzuki and coworkers incorporated an oxo-vanadium ion into cross-linked polystyrene resins functionalized with iminodiacetic acid or diethylenetri-amine derivatives (Scheme 57), which afforded a heterogeneous catalyst that can promote... 

Phenolic, (I), and naphtholic, (II), condensation polymers containing cyclopentane were previously prepared by Sue et al. (1). These materials were subsequently epoxidized with epichlorohydrin and used in electronic devices as ICs and Lumen solubility indexes (LSIs). In a subsequent investigation by Abe et al. (2) novolak resins functionalized with thiophene, (III), were prepared and used as adhesives. 

Table 4.6). Specifically, the methods used were to (1) add a tag (type of atom or physical change tracked in these calculations) (2) remove a tag element from the resin during reaction or (3) use a tag element unique to the resin before and after reaction. Error was estimated by accessing limitations of elemental analyses and known resin functionalization error. While the third case listed could not be applied to the phenylacetylene... 

The kinetics of ligand exchange between [M(dik)4] (M = Zr or Hf dik = acac or tfacac) and the corresponding free /3-diketones have been studied by Adams and Larsen.233 [Zr(acac)4] exchanges ligands with a polystyrene resin functionalized with acetylacetonate groups to give a polymer-bound zirconium complex.234... 

Oxovanadium(V) and oxomolybdenum(VI) were incorporated into crosslinked polystyrene resins functionalized with iminodiacetic acid or diethylenetriamine derivatives 921 The polymer complexes were used as catalysts in the oxidation of olefins with f-butylhydroperoxide. Vanadium(V) complexes promote the epoxidation of allylic alcohols in a highly regioselective manner, e.g., 2,3-epoxide was obtained in 98 % selectivity from e-geraniol at 80 °C. The catalytic activity of the vanadium(V) complexes is generally higher than that of the molybdenium(VI) complexes in the oxidation of allylic alcohols, whereas an opposed trend holds for the epoxidation of cyclohexene. 

We found that at lower levels of resin functionalization a clear positive was difficult to observe. 

This test gave excellent results in both of its forms (testing for primary and for secondary amines) a clear positive was observed even at low levels of resin functionalization for the sterically hindered Aib. 

Scheme 15.8 (a) Polystyrene resin functionalization with carboxylic acids (b) substituted tetrazole synthesis on solid phase. 

We are interested in the application of polymers as adsorbents, ion exchangers, fuel cells, and permeable materials. In this regard, the first resins with some of these properties were obtained by D Aleleio in 1944 based on the copolymerization of styrene and divinylbenzene. Unfunctionalized polystyrene resins cross-linked with divinylbenzene (Amberlite) are widely applied as adsorbents [191,192], In addition, the polystyrene-divinylbenzene resins functionalized with sulfuric acid (sulfonation) to create negatively charged sulfonic sites are applied as cation exchangers, and treated by chloromethylation followed by animation produce anionic resins [193,194],... 

Resin as the Disperse Phase. Several kinds of resins (10) have been used to reinforce rubbers—e.g., phenolic or coumarone resins for natural rubber, styrene-butadiene resin for styrene-butadiene rubber, etc. One other important system, pressure-sensitive adhesive, also belongs to this class. These adhesives generally contain a low molecular weight resin functioning as a tackifier. In 1957, Wetzel (68) and Hock (19) found that these adhesives were actually two-phase systems (Figure 1). Under... 

Other fractionation systems that employ resins have been advocated. In one, the hydrazine salt of sulfonate resins functions by virtue of its relatively greater retardation of D-glucose as compared to D-fruc-tose.54 In this process, D-fructose appears in the eluate first, followed by the D-glucose fraction. 

Hi. The monomer polymerization route. Compared with the resin-functionalization route, the homo- and copolymerization of organotin-containing monomers permits one to influence the polymer resin structure to a greater extent. In principle, it is possible to prepare gel-type, macroporous, microporous or nonporous polymers. The pore structure, tin loading, solubility and other factors which influence the reactivity of the polymer-supported organotin reagents can be controlled by appropriate... 

The most popular method by which epoxy thermoset structure is altered for structure-property investigations is the intentional variation of the curative/epoxy resin functional group ratio (A/E). Unfortunately, it is impossible to alter independently only one structural feature at a time using this technique. For example, the... 

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