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A novel chemically and mechanically stable polymer support for solid-phase peptide synthesis with excellent swelling performance in various organic solvents is described. The crosslinked polymer in its bead form was prepared by the aqueous suspension polymerization of the styrene and tri(propylene glycol) glycerolate diacrylate. The support is unique because the hydroxyl group is introduced into the polymer support in the polymerization step itself, which makes it highly cost effective. The hydroxyl functionality of the crosslinker in the polymer was used as a growth site for peptide synthesis, thus minimizing the incompatibility arising because of the styrene core as compared to styrene-based polymer supports currently used in polypeptide synthesis. The utility of the resin for solid-phase peptide synthesis was tested by the synthesis of a 19-residue peptide amide of the envelope region of hepatitis C viral polyprotein and was compared with Merrifield resin by the 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyl uronium hexafluoro phosphate/1-hydroxy benzatriazole method with a Rink amide linker. The molecular character of the polymer and the extent of crosslinking density on the dependence of the reactivity of the attached amino groups were investigated by a reactivity study of the amide bond formation of a model Val-Ala dipeptide. Enhanced swelling, the increased rate of aminoacylation, and the high purity of the peptides synthesized on the novel support highlighted the influence of the polarity of the solid support in the solid-phase synthesis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 288–294, 2004

An efficient crosslinked polymer support was synthesized by introducing 1,4-butanediol dimethacrylate crosslinker to a polystyrene network using aqueous suspension polymerization technique. The support was functionalized with aminomethyl groups using chloromethyl phthalimide. The kinetics of amide bond formation on 1,4-butanediol dimethacrylate crosslinked polystyrene (PS-BDODMA) polymer were carried out using the attachment of Rink amide linker as a model reaction. The efficiency of the support was tested and compared with Merrifield resin by following different steps involved in the synthesis of a 14-residue model peptide, Lys-Ile-Asn-Thr-Asn-Ala-Ser-Trp-His-Ala-Asn-Arg-Thr-Ala-NH2, under the same synthetic conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2897–2903, 2003

A copolymer of 1,6-hexanediol diacrylate (HDODA) and styrene was prepared by a suspension polymerization method. The resin was characterized by infrared and carbon-13 cross-polarization magic-angle spin ( 13 C CP-MAS) spectroscopy. The topology of the resin was examined by scanning electron microscopy (SEM). The polymer swells extensively in common solvents used for peptide synthesis. The resin exhibited chemical stability even in neat trifluoroacetic acid. The applicability of the new resin was demonstrated by synthesis of Val-Ala-Val-Ala-Ala-Gly, Gln-Val-Gly-Gln-Val-Glu-Leu-Gly, and Val-Gln-Ala-Ala-Ile-Asp-Tyr-Ile-Asn-Gly. Comparative synthetic studies showed that the new resin is superior to divinylbenzene (DVB)-based resin in the case of the synthesis of hydrophobic peptide sequences.

Metal-ion complexation behavior of glycine functions supported on divinylbenzene (DVB)- and N,N'-methylene bisacrylamide (NNMBA)-crosslinked polyacrylamide was carried out toward Co(II), Ni(II), Cu(II), and Zn(II) ions. The polymeric ligands and the derived metal complexes were characterized by IR, UV, and EPR spectra and by SEM. The metal-ion complexation of the rigid DVB-crosslinked system is lower than that of the semirigid NNMBA-crosslinked system. The glycine ligands renervated after the desorption of the metal ions showed an unusual specificity toward the desorbed metal ion. The low degree of crosslinking makes the desorption process simple and shows fast rebinding kinetics. The metal-ion-desorbed polymeric ligands would have pockets or holes characteristic of the desorbed metal ion, resulting in its specific rebinding. The rigidity of the crosslinking also determines the kinetics of metal-ion rebinding. The specificity and selectivity characteristics of the crosslinked polymeric ligand was found to be increased as the crosslinking agent changes from semirigid NNMBA to rigid and hydrophobic DVB. Thus, copper-desorbed resins showed an increased specificity toward copper ions and selectively binds copper ions from a mixture of copper and cobalt ions. The metal-ion specificity and selectivity characteristics of the metal-ion-desorbed system is exploited for the concentration of desorbed metal ions from a mixture of metal ions. The resin is amenable for a continuous process and can be regenerated several times.

Three short peptides were synthesized on Merrifield resin (PS–DVB) and on polystyrene crosslinked with 1,6-hexanediol diacrylate resin (PS–HDODA) to compare their efficiencies in solid-phase peptide synthesis (SPPS). A 2% crosslinked polymeric system having almost equal capacity was used in both cases. The peptides were synthesized using standard solid-phase methodology. In the case of the PS–HDODA resin, all the couplings were completed by the first coupling and the peptides were obtained in > 90% yield and > 95% purity. But in the case of the PS–DVB resin, most of the attachments require two to three couplings and the peptides were obtained in about a 65% yield. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1933–1939, 1999

Styrene and tetraethylene glycol diacrylate (TTEGDA) were copolymerized by the free radical aqueous suspension polymerization technique, employing toluene as the monomer diluent at 80°C. The resulting beads were functionalized by chloromethylation. The copolymer was characterized by IR and high-resolution solid-state 13C-NMR techniques. Scanning electron microscopy was employed to observe shape, size, and morphological features of the crosslinked bead copolymer. The swelling capacities of the copolymer were measured in various solvents. Reactivity of the amino functionalized polymer was compared with divinylbenzene-polystyrene (PS) resin. Stability of the copolymer was tested under various peptide synthetic conditions. High capacity chloromethyl TTEGDA-crosslinked PS was employed as a solid support in the synthesis of the hydrophobic peptide Boc(Ala-Leu-Ala)4-OMe. The coupling and deprotection steps in the synthetic scheme proceeded in near quantitative yields, supporting the positive role of the flexible and hydrophilic crosslinking agent. The fully protected 12-residue peptide was cleaved from the support by a transesterification procedure in 85% overall yield and characterized by thin-layer chromatography, amino acid analysis, and 1H-NMR. © 1996 John Wiley & Sons, Inc.

About 40–70% of the applied urea fertilizer is lost to the environment, causing serious pollution. Controlled-release technology is useful in increasing the efficiency of fertilizer urea as well as in checking environment pollution. Four laboratory-level controlled-release urea fertilizers were formulated based on polymers which are soil conditioners and then evaluated for their slow-release property. Urea was coated with the copolymer of acrylamide and divinylbenzene/N,N′-methylenebisacrylamide /tetraethyleneglycol diacrylate or pentaerythritol triacrylate and sealant materials (wax and polystyrene). Urea coated with co-polymer of acrylamide-tetraethyleneglycol diacrylate was found to be having a better slow-release property among the systems prepared. © 1996 John Wiley & Sons, Inc.

Amino functions were incorporated into triethyleneglycol dimethacrylate (TEGDMA)-crosslinked (2–20 mol %) polyacrylamides by transamidation with ethylenediamine. The complexation of these polymeric ligands with the amino function in different structural environments was investigated toward Cr(III), Mn(II), Fe(III), Cu(II), Cd(II), and Pb(II) ions. The metal ion intake decreased with the extent of the crosslinking and followed the order Cu(II)>Cr(II)>Mn(II)>Fe(III)>Pb(II)>Cd(II). The pH dependence of complexation and distribution coefficient; time course and kinetics of complexation; swelling properties of the uncomplexed and complexed resins in water; recyclability; infrared (IR) spectra; electron paramagnetic resonance; ultraviolet visibility; magnetic susceptibility; and thermogravimetric and scanning electron microscopy studies were carried out. The kinetics of complexation was found to be first order. The swelling of the complexed resins is lower than that of the uncomplexed resins. Complexation resulted in the lowering of the IR absorption of the amino ligands. The IR data of the TEGDMA-crosslinked polyacrylamide amine and the corresponding Cr(III) complex reveals that the metal is coordinated with the ligand through the amino nitrogen. The SO=4 is also coordinated. The number of coordinated nitrogen atoms varies as the hydrophilicity and flexibility of the polymer change with the crosslinking. Thus spectral and magnetic studies suggest a distorted octahedral geometry for Cu(II) complexes, octahedral geometry of the d3 system for Cr(III), and d5 high-spin octahedral geometry for Fe(III) and Mn(II) complexes. The thermal stabilities of the complexed resins increase with increase in the metal content. Surface morphology of the polymeric ligand changes on complexation. © 1996 John Wiley & Sons, Inc.

Papain was immobilized on polymer supports with spacer arms of varying nature and length. As the length of the spacer arm increased, there was a marked increase in the extent of enzyme immobilization and activity of immobilized enzymes. When a long, flexible and hydrophilic polyethylene glycol spacer was introduced between the polystyrene backbone and the functional group used for immobilization, the extent of coupling and enzyme activity increased. Dependence of enzyme activity on the nature and extent of crosslinking and on the nature of the polymeric backbone was investigated. Hydrophilic polyacrylamide-based supports were found to be more efficient supports for immobilization compared to hydrophobic polystyrene-based supports.

A crosslinked polystyrene–supported solid-phase analogue of t-butyl hypochlorite containing a trimethylene spacer group between the polymer matrix and the t-butyl hypochlorite function was prepared and used as a recyclable oxidizing reagent for alcohols. The synthetic route to this new polymeric reagent involved a seven-step polymer-analogous reaction starting from styrene-divinyl benzene 2%-crosslinked polymer. A β-ketopropionic acid function was introduced into the polystyrene matrix by Friedel–Crafts reaction with succinic anhydride. The keto function in the resulting polymer (2) (capacity, 3.57 meq of COCH 2 CH 2 COOH/g) was converted to the methylene group by Clemmensen reduction using zinc amalgam and HCl. The carboxyl function in the product polymer (3) was converted to the acylmalonic ester function by malonic ester synthesis through the reaction of the polymeric acid chloride (4) with ethoxymagnesium diethylmalonate. The polymeric acyl malonic ester (5) was decarboxylated to yield the 2-oxopentyl polystyrene resin (6). This on Grignard reaction with methyl magnesium iodide followed by hydrolysis afforded the polystyrene derivative with the t-butyl alcohol function separated by three methylene groups (7). The t-butyl alcohol resin (7) was converted to the corresponding hypochlorite resin (8) by reaction with sodium hypochlorite. The resin was found to have a capacity of 2.84 mmol Cl/g by iodometric analysis. The capacities of the resins 2-8 were determined from the weight changes in the corresponding conversions and verified by quantitative determination of the functional groups. This new hypochlorite was found to oxidize alcohols to carbonyl compounds in 85-98% yield. The oxidizing efficiency of this new reagent was found to be significantly greater than those of the reagents containing only one spacer and no spacer between the reagent function and the polymer support. The presence of a 3-methylene spacer also facilitated the hypochlorite formation step significantly.