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An efficient cross-linked polymer support for solid-phase synthesis was prepared by introducing glycerol dimethacrylate cross-linker to polystyrene network using free radical aqueous suspension polymerization. The support was characterized by various spectroscopic methods. Morphological feature of the resin was analyzed by microscopy. The polymerization reaction was investigated with respect to the effect of amount of cross-linking agent, which in turn vary the swelling, loading, and the mechanical stability of the resin. The solvent uptake of the polymer was studied in relation to cross-linking and compared with Merrifield resin. The stability of the resin was tested in different synthetic conditions used for solid-phase peptide synthesis. Hydroxy group of the support was derivatized to chloro and then amino groups using different reagents and reaction conditions. Efficiency of the support was tested and compared with TentaGel™ resin by following different steps involved in the synthesis of the 65–74 fragment of acyl carrier protein. The results showed that the poly(styrene-co-glycerol dimethacrylate) (GDMA-PS) is equally efficient as TentaGel resin in peptide synthesis. The purity of the peptides was analyzed by HPLC and identities were determined by mass spectroscopy and amino acid analysis. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4382–4392, 2005

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 highly flexible, mechanically and chemically stable copolymer, tri(propylene glycol) glycerolate diacrylate cross-linked polystyrene (PS-TRPGGDA), was synthesized by the suspension polymerization and employed as a solid support for peptide synthesis. The beaded polymer support containing secondary hydroxyl functional groups in the cross-linker was used as the growth site for peptide synthesis. The procedure is unique and cost-effective in that it avoids the initial functionalization steps required for most of the styrene-based polymer supports. The resin was characterized by 13 C-CP-MAS NMR spectroscopy and the morphologic features of the resin were investigated using scanning electron microscopy. Swelling studies conducted on the new support revealed that the PS-TRPGGDA resin undergoes more effective swelling and solvation than PS-DVB resin in all solvents used in peptide synthesis. The efficiency of the new support was demonstrated by synthesizing a 'difficult' sequence Ala-Arg-(Ala) 6 -Lys and comparing it with commercially available Merrifield and Sheppard resins. The synthetic efficiency was further demonstrated by the synthesis of a 24-residue NR 2A peptide substrate of calcium/calmodulin-binding peptide. The high yield and purity of the peptide synthesized on the novel support indicates the positive role of the flexible and hydrophilic cross-linking agent in the solid support.

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.

A highly solvating copolymer was prepared in high yield by introducing a flexible crosslinker, 1,4-butanedioldimethacrylate, into the polystyrene matrix by a free radical aqueous suspension polymerization. A 2 mol% crosslinked resin showed rigidity and mechanical characteristics comparable to those of divinylbenzene-crosslinked polystyrene (Merrifield resin, DVB-PS) support. Swelling and solvation characteristics of the new resin, BDDMA-PS, were much higher than DVB-PS support in all solvents used for solid phase peptide synthesis. The diacrylate crosslinks in the resin network were found to be highly stable even after 48 h treatment with neat TFA, 6 N HCl and 6 N KOH at 110°C. To demonstrate the usefulness of the new resin in high capacity peptide synthesis, a typical difficult peptide, acyl carrier protein (ACP) fragment (65–74), was synthesized on commercially available 1 mol% crosslinked DVB-PS and 2 mol% crosslinked BDDMA-PS resins under identical conditions. A protocol using NMP/DMSO mediated coupling was employed for chain assembly. The yield and purity of the product from BDDMA-PS resin was higher than when the DVB-PS resin was used. The mechanistic reason behind the synthetic efficiency of the new resin was found to be its ability to induce random coil conformation to the growing peptide chains. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.

Peptides were synthesized with very high purity and yield on a highly solvating copolymer of 1,4-butanediol dimethacrylate cross-linked polystyrene support (PS-BDODMA). The polymer was synthesized by radical aqueous suspension polymerization using toluene as the diluent and 1% polyvinyl alcohol as the suspension stabilizer. The supports were highly resistant to various chemical reagents and solvents that are frequently used in polypeptide synthesis. The peptides synthesized on this support were designed from the core (C), envelope (E1 and E2) and nonstructural protein (NS1-NS5) regions of the prototype hepatitis C viral (HCV) polyprotein, and were used to develop a peptide-based immunoassay (PBEIA) for the detection of HCV antibodies. The purity of these peptides was tested by HPLC. Peptide identity was confirmed by amino acid analysis and MALDI-TOF-MS. A single peptide chosen from a conserved area (E2/NS1) at the C-terminus of the hypervariable region (HVRI) was found to be sufficient for effective and reliable diagnosis of HCV infection in infected individuals, as well as also apparently healthy individuals. The CD spectrum of the peptide shows no preference for any ordered secondary structure. When used, peptide mixtures from various protein regions of HCV reduced the sensitivity and reliability of the diagnosis partly because of epitope masking.

Four peptides were designed and synthesized on a highly solvating copolymer of tetraethyleneglycol diacrylate cross-linked polystyrene (PS-TTEGDA) support with very high purity and yield. The polymer was synthesized in various cross-linking densities (1, 2, 3, 4, 5 and 10%) using radical aqueous suspension polymerization. Four per cent PS-TTEGDA resin showed rigidity and mechanical characteristics comparable with those of divinylbenzene cross-linked polystyrene (PS-DVB) support. Swelling and solvation characteristics of PS-TTEGDA were much higher than PS-DVB support in all solvents used in solid-phase peptide synthesis. Forty-eight hour treatment of the support with neat trifluoroacetic acid did not show any change in its infrared spectra. PS-TTEGDA could be functionalized with chloromethyl, aminomethyl and hydroxymethyl functional groups under various controlled conditions. Synthetic utility of the support was demonstrated by the synthesis of four peptides selected from the envelope and nonstructural protein region of the prototype hepatitis C virus (HCV). These peptides were later used successfully to develop a peptide-based immunoassay (PBEIA) for the detection of HCV immunity. Peptides designed from the NS1 and NS4 protein regions were found to be very promising for the development of a new diagnostic kit to detect HCV infection in human blood. Peptide purity was tested by RP-FPLC and the peptide identity was confirmed by amino acid analysis.

Tartrate-functionalized polystyrene copolymers were prepared with divinyl benzene, tetraethyleneglycol diacrylate, and diallyl tartrate as the crosslinking agents. These insoluble materials possessed the unique advantages of heterogeneous reagents. These resins were used to support the asymmetric epoxidation of allylic alcohols along with titanium tetraisopropoxide and tert-butyl hydroperoxide with reasonably good yields and a high enantiomeric excess. The swelling behavior and molecular architecture of the polymer backbone significantly influenced the effectiveness of the catalyst. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 161–169, 2000

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.

The synthesis of three hydrophobic peptides, which are partial sequences of thioredoxin, on a newly developed, flexible 1,6-hexanediol diacrylate cross-linked polystyrene, in good yield and purity, is described.

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.

The N,N′-methylenebis(acrylamide) (NNMBA)-crosslinked polyacrylamide supported amino ligands undergo complexation with Cr(III), Mn(II), Fe(III), Pb(II) and Cd(II) ions. Complexation is maximum for Cr(III) ion. The metal intake decreases as the crosslinking increases. The NNMBA resin can be reused after complexation and desorption without appreciable reduction in amino capacity. The IR spectrum of the Cr(III) complex gives an additional peak for sulfate complexation and the amino peak undergoes a negative shift, which is a clear evidence of metal coordination through the amino nitrogen. EPR, electronic spectra and magnetic moment are indicative of a distorted geometry for Cu(II), Cr(III), Fe(III) and Mn(II) complexes. Cd(II), Pb(II) complexes are diamagnetic. Complexation brings about vivid changes in the surface morphology of polymeric ligand. The thermal stability of Cr(III) complex increases as the metal content increases.

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.

The water binding properties of crosslinked copolymers of acrylamide with tetraethyleneglycol diacrylate triethyleneglycol dimethacrylate, N,N'-methylene bisacrylamide and divinylbenzene were investigated. It was observed that the freezing water contents of these copolymers depend on the nature of the monomers and crosslinkers, as well as on the extent of crosslinking

Polymeric amines derived from copolymers of acrylamide (AA) cross-linked with bifunctional crosslinking agents of varying polarity and hydrophilicity were studied for their reactivity in the aminolysis of N-benzoylglycine 4-nitrophenyl ester. The reaction did not follow simple kinetics. © 1995 John Wiley & Sons, Inc.

Supports of polystyrene (PS) crosslinked with divinylbenzene (DVB) with varying crosslink densities were prepared and furnished with 1,2-diketo functions through a series of polymer-analogous reactions. Crossed benzoin condensation between polymeric aldehyde (formylated polystyrene) and substituted low-molecular aldehydes gives a set of mixed α-hydroxy ketones. These polymeric benzoin analogues were converted to α-diketones by oxidation. The polymeric systems containing α-diketo functions were subjected to rearrangement under basic conditions into hydroxy acids. The products were characterized by IR and 13C CP-MAS NMR spectroscopy and by chemical methods. The rearrangement was observed to be facile in these highly crosslinked networks in spite of the environmental constraints imposed by the rigid and high-molecular-weight polymeric backbone. Durch eine Folge polymeranaloger Reaktionen wurden Poly(styrol-co-divinylbenzol)-Netzwerke mit 1,2-Diketo-Gruppen funktionalisiert. Eine gekreuzte Benzoin-Kondensation zwischen einem polymeren Aldehyd (formyliertes Polystyrol) und substituierten niedermolekularen Aldehyden lieferte eine Reihe gemischter α-Hydroxyketone, die zu α-Diketonen oxidiert und anschliesend unter basischen Bedingungen zu Hydroxysauren umgelagert wurden. Die Produkte wurden mittels IR- und 13C-CP-MAS-NMR-Spektroskopie und mit chemischen Methoden charakterisiert. Trotz des steifen und hochmolekularen Polymerruckgrates verlauft die Umlagerung leicht in den hochvernetzten Netzwerken.

Crosslinking copolymerization of styrene with divinylbenzene, butanediol dimethacrylate and ethyleneglycol dimethacrylate in the presence of benzil in the dissolved state results in benzil-encapsulated crosslinked polymers. Resins with various crosslink densities were prepared by adjusting the monomer/crosslinker ratio. The benzil entrapped in the cavities was subjected to benzil-benzilic acid rearrangement. The precursor resins and the rearrangement products were characterized by IR and 13C NMR spectroscopy. The surface properties of polystyrene and benzil-encapsulated polystyrene were compared by scanning electron micrography.

The complexation behaviour of dithiocarbamate functions supported on polyacrylamides with varying extents (2-20 mol%) of N,N′-methylene-bis-acrylamide (NNMBA) crosslinks was investigated. The crosslinked polyacrylamides were prepared by the free radical solution polymerization of the monomers in water at 80°C using potassium persulphate as initiator. The dithiocarbamate ligands were introduced by polymer-analogous reaction involving transamidation with ethylenediamine and dithiocarbamylation with carbon disulphide and alkali. The complexation behaviour of these dithiocarbamate resins with the ligand functions in different macromolecular environments were investigated towards Co(II), Ni(II), Cu(II), Zn(II) and Hg(II) ions by a batch equilibration technique. The metal ion intake varied with the extent of the NNMBA-crosslinking. Thus the 8% crosslinked system has the highest complexation capacity. The values for metal ion intake followed the order Hg(II)> Cu(II)> Zn(II)> Ni(II)> Co(II). The time-course of complexation, the possibility of recycling and the swelling characteristics of the uncomplexed and complexed resins were considered, and IR characterization and thermal studies were undertaken. The swelling values of the complexed resins are lower than those of the uncomplexed resins. The thermal stability of dithiocarbamates varied with the extent of NNMBA-crosslinks and with the metal ion.

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.

Acrylamide was copolymerized with N,N′-methylene-bis-acrylamide (NNMBA), tetraethyl-eneglycol diacrylate (TEGDA), and divinyl benzene (DVB) in different proportions to afford crosslinked polyacrylamides with varying nature and extent of crosslinking. These insoluble polymers were functionalized with the N-bromoamide function and the reactivity of the resulting polymeric N-bromoamide was investigated under different conditions. The capacities of the reagents varied from 6.7 mequiv / g for the linear polymeric reagent to 1.1 mequiv / g for the 15% DVB-crosslinked reagent. Oxidation of benzoin to benzil was used as the model reaction. Investigation of the reaction under different conditions of solvent and varying molar excess revealed a significant influence of the nature and extent of crosslinking in deciding the extent of reaction. In the case of NNMBA-crosslinked reagents, the reactivity increased up to 10% crosslinking and then decreased. The reactivity of the reagents increased up to 15% crosslinking in the case of TEGDA-crosslinked ones and for DVB-crosslinked reagents the reactivity decreased with crosslinking. The polarity of the crosslinking agent and its molar percentage on the polymeric reagent (crosslink density) are factors affecting the solvent compatibility, which in turn, is decisive in the facilitation of the reactions.

When α‐oxoketene dithioacetals 1a–n were treated with the bromine complex of a copolymer of 1‐vinyl‐2‐pyrrolidone and 4‐vinylpyridine, the corresponding thiolcarboxylates 2a–n were formed in excellent yields. The reaction also works with other 1‐vinyl‐2‐pyrrolidone‐derived polymers as well as commercially available polyvinylpyrrolidone–bromine complexes. The method is suitable for preparing aliphatic, aromatic, and γ,δ‐unsaturated β‐oxothiolcarboxylates.

Crosslinked poly(4-vinylpyridine) and poly(4-vinylpyridine-co-styrene) were functionalized with permanganate group to afford the corresponding poly[4-vinyl(pyridinium permanganate)] resin. These resins were found to selectively oxidize alcohols to corresponding carbonyl compounds. These insoluble functionalized polymers possess the desired characteristics of the polymeric reagents, including operational simplicity, filterability, and regenerability. The influence of solvent, duration of reaction, and molar excess of the reagent in these oxidation reactions was investigated to find out the optimum conditions for effective oxidation reactions. The reactions were found to be more facilitated in nonpolar solvents, and a large excess of the polymeric reagent did not have any significant effect on the extent of reactions. The poly[4-vinyl(pyridinium permanganate)] resin bears a contrast to KMnO4 and other polymer-supported oxidizing agents like poly[4-vinyl(pyridinium chlorochromate)] in that it does not bring about the oxidation of the alcohol group directly attached to the ring structure.

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.

Poly(ethylene glycol)s grated onto suitably functionalized, crosslinked polystyrenes were introduced as a new class of multidetachably immobilized hydrophilic macromolecular supports for the synthesis of peptides. This new polymeric carrier system facilitates both the homogeneous solvation of the reaction site and the insolubilization of the substrate, which are prerequisites for an efficient multistep synthesis using polymeric supports. In these support systems, a strongly solvated hydrophilic linear chain molecule, poly(ethylene glycol) (PEG)1 , is attached to an insoluble, crosslinked polystyrene through suitable anchoring linkages. At the free chain end of this supported PEG, amino acid residues were stepwise incorporated following the standard synthetic methodology for peptides. A special feature of these new carriers is that the use of an orthogonal set of anchoring linkages to connect the polystyrene, PEG and the peptide provides access to the PEG-bound solubilized peptide or to the free peptide, as desired. The applications of these new polymeric supports are illustrated by the synthesis of thioredoxin partial sequences in the free and PEG-bound solubilized forms.

The conformational properties of three series of monodispersed, chemically and optically pure, PEG1 -bound linear host oligopeptides of the general formula and [X = Ala, Glu(OBzl)] containing a single guest L-Pro residue at different positions in the main chain have been investigated in aqueous and alcoholic solutions as a function of concentration, temperature, and added salts using CD. The corresponding N-deblocked peptides have also been examined. The incorporation of the L-Pro residue into a host petide chain blocks the extension of the α-helical conformation at the level of the segment containing the guest residue at its N-terminal end. The investigations reveal asymmetric helixnucleation properties of the L-Pro residue as predicted by theory. In β-structure-forming oligopeptides, the insertion of a L-Pro residue results in a significant destabilization of the ordered conformation. Thus, aggregation of peptide chains is less pronounced in these co-oligopeptides.