WO2002020630A1

WO2002020630A1 - Process for the preparation of glycerol-based crosslinked polymeric gels

Info

Publication number: WO2002020630A1
Application number: PCT/CH2000/000482
Authority: WO
Inventors: V. N. Rajasekharan Pillai; Boopathy Dhanapal
Original assignee: Lipal Biochemicals
Priority date: 2000-09-08
Filing date: 2000-09-08
Publication date: 2002-03-14
Also published as: AU2000268148A1

Abstract

The present invention relates to a process for the preparation of crosslinked polymeric gels for solid phase synthesis, the respective gels and their use. The gels are prepared by radical-induced copolymerisation of monomeric molecules and bifunctional crosslinking agents.

Description

PROCESS FOR THE PREPARATION OF GLYCEROL BASED CROSSLINKED POLYMERIC GELS

SUMMARY OF THE INVENTION

The present invention relates to the development of processes for preparing a new class of crosslin ed polymeric gels of the general structure (I) derived from glyc- erol/glycerolyl diglycerolate diacrylate/dimethacrylate (II) and vinyl monomers (III). Said processes involve radical-induced copolymerisation of the monomers III and the crosslinking agents II in differing ratios depending on the respective application of the resulting polymeric gel, wherein said monomers and crosslinking agents are either in emulsion, bulk, solution or suspension. The invention also relates to the preparation of derivatives of polymeric gels of the general formula I by chemical modification of their functional groups leading to a variety of functional resins finding application in general organic synthesis, peptide synthesis, combinatorial organic synthesis, enzyme immobilization, in biochemical transformations and bioorganic chemistry.

x = 2, 5, 10, 15, 20, 25

(I) R1 = P ; CONH₂

R2 = H; Me

(II) R2 = H; Me

(III) R1 = Ph; CONH₂

Thus, the processes for the conversion of the hydroxyl groups in said polymeric gel of the general formula I to chloro, bromo, amino, bromobenzyl, 3-nitrobromobenzyl and 4-oxybenzylalcohol are also objects of the present invention, x in the general formula covers any percentage between 0 and 100. Further objects of the present invention are all substances of the general formula I and derivatives thereof per se, their manufacture and functionalization with groups, anchoring linkages and spacers which are prevalent in polymer supported methods of peptide synthesis.

Moreover, the present invention comprises the various gels and their respective applications.

BACKGROUND OF THE INVENTION

Polymer-supported solid phase organic chemistry and bio-organic chemistry witnessed a rapid evolution during the past decade owing to the enormous potential of peptide and non-peptide libraries in bioorganic chemistry, medicinal chemistry and chemical biology. Applications of combinatorial peptide synthesis and parallel organic synthesis in drug industry fuelled unprecedented challenges in peptide research and newer methods for the efficient synthesis of peptides and related systems. Realizing the full potential of synthetic peptides, new strategies for rapid synthesis and testing of large numbers of peptides needed to be developed. Syn- thesis of biologically active peptides for clinical purposes, protein sequences for modern biological research and model peptides for conformational and other phys- icochemical studies require a strategy which enables a side-product-free preparation of every intermediate and allows analytical procedures for ineffective control of reactions and purity of the sequential peptides. The classical liquid phase method has been employed extensively for the synthesis of peptides of short- to medium-sized sequences. The preparation of large peptides using this procedure is still rather laborious. This is because after each coupling step, the intermediate peptide has to be isolated, purified and characterized before proceeding to the next step. In 1 963 Bruce Merrifield introduced the Solid Phase Peptide Synthesis (SPPS), in which the C-terminal amino-protected amino acid is covalently linked to a functionalized crosslinked polystyrene support; deprotection and stepwise assembly of the alpha-amino protected amino acid residues are continued till the desired peptide sequence is formed, which is finally cleaved and purified. This method during the last 37 years has revolutionized peptide research and several innovations in solid phase method have been put forward during these 3 decades (Merrifield, J. Amer. Chem. Soc. 1 963, 85, 2149-21 54; Mutter and Pillai, Top. Curr. Chem.. 1 982, 106, 1 19; Tarn and Merrifield, J. Amer. Chem. Soc, 1980, 102, 61 1 7; Rapp & Bayer , Peptides 1989, Meldal, Tetrahedron Lett. , 1 992, 33, 3077-3080; Pillai and Mutter, Ace Chem. Res.. 1 981 , 14, 1 22-1 30; Pillai & Var- key, J. Pept. Res. 198, 51 , 49; Kumar, Roice and Pillai, Macromolecules, 1999, 32, 8807-881 5; Tetrahedron. 2000, 56, 3725-3734; Arunan and Pillai, Tetrahedron, 2000, 56). 1 -2% DVB crosslinked polystyrene supports and their functionalized derivatives have been extensively used for the synthesis of a large number of peptides. However, side reactions still plague many specific syntheses often resulting in low yields and poor homogeneity of the target peptide sequences, especially when the number of amino acid residues exceeds twenty. The rate of incorporation of amino acid residues has been found to be decreasing with increasing chain length.

The main reasons for the low yield and purity in such cases are the physicochemi- cal incompatibility of the divinylbenzene-crosslinked polystrene matrix with the attached peptide and the development of unfavorable conformational characteris- tics of the growing peptide and protein sequences (Meienhofer, Biopolvmers, 1 981 , 20, 1761 ; Mutter, Maser, Bode and Pillai, Adv. Polvm. Sci. 1 984, 65, 177). The influence of mass transport of reagents, solvation of polymeric support as well as the peptide, reaction rates of the coupling step and deprotection have been mostly negative in such cases. This is particularly prominent in the synthesis of hydrophobic peptides where there is enhanced aggregation with increasing chain length. The synthesis of peptides containing more than 5 to 6 hydrophobic residues like Val, Leu, lie has always been a difficult task in all the polymer-supported methods and in the conventional solution phase method of peptide synthesis. The physicochemical incompatibility of the crosslinked polymeric network with the growing peptide chain is the major disturbing factor in achieving quantitative reaction for coupling, deprotection and cleavage reactions. This is also the major structural factor responsible for the solvent-compatibility and solvent-swellability of the various resins currently in use for peptide synthesis and other general organic syn- thesis.

Several modifications have been introduced to overcome the difficulties associated with the DVB-crosslinked polystyrene resins. Polystyrene-polyethylenglycol graft copolymers and Polyethyleneglycol-polyacrylamide (PEGA) and crosslinked ethoxylate acrylate resins (CLEAR) have been developed to increase the polarity of the support and to make the systems more compatible with the growing peptide chain. In all such strategies, post-polymerization modifications and polymer- polymer reactions are necessary for the development of the resins usable for peptide synthesis. Moreover, the mechanical stability of these resins is not optimal.

Synthesis of biologically active peptides for research and clinical purposes requires strategies that enable homogeneous synthesis of every intermediate and allow analytical procedures to control the reactions and purity of the sequential peptides. The efficiency of a solid support for solid phase organic synthesis, peptide synthe- sis and for other bioorganic chemical applications depends upon its mechanical stability, swellability and compatibility with a wide range of solvents of varying polarity. The physicochemical incompatibility of the polymeric resin with the growing peptide substrate is the major factor affecting the peptide synthesis on polymeric supports.

GENERAL DESCRIPTION OF THE INVENTION The present invention overcomes all of the above difficulties by adjusting the hy- drophilicity-hydrophobicity balance of the polymeric support taking into consideration the hydrophobicity-hydrophilicity balance of the peptidic or other substrates. The desired hydrophilicity-hydrophobicity characteristics can be controlled, as per the invention of these glycerogels, by a judicious choice of the monomer and the crosslinking agent and adjusting their relative amounts in the polymerization mixture. In contrast to the widely used crosslinked polystyrene functionalized resin supports, the glycerogels of the present invention have the advantage that there is no need of the initial chloromethylation reaction for functionalization reaction. The resins, which are obtained in one-step polymerization reactions, as per this inven- tion, can be directly used as supports without the need of additional functionalization. For specific cleavage procedures, conventional in the art and practice of solid phase peptide synthesis, the hydroxyl functional groups in these glycerogels can be converted to a wide variety of anchoring linker groups by efficient polymer- analogous reactions. The fact that the crosslinking difunctional monomer itself provides a latent functionality for starting or carrying out a multitude of organic and bio-organic synthetic reactions is a unique and novel feature of these new polymeric systems. The new resins are chemically inert to all reaction conditions generally encountered in solid-phase organic synthesis and peptide synthesis; at the same time the resin-bound functional groups are much more reactive compared to the functional groups on the existing resin supports. The shape, size and morphological characteristics of these new glycerogels make the system suitable for easy handling, higher purity and yield by making use of these glycerogels. The functional group capacity, which determines the carrier capacity of a resin in solid- phase organic synthesis is varied at will, as per this invention, to suit to the re- quirement of the peptide or protein sequence in question. The capacity can be kept at a high value without affecting the facilitation of the synthetic reactions. The analytical follow-up of the reactions is easier compared to the existing systems. Peptides that can be obtained in the glycerogels are especially suited for the syn- thesis of hydrophobic peptides, which are otherwise difficult to prepare. Peptide aggregation in the case of beta-structure forming peptides is avoided in these new glycerogels due to the tailor-designed optimum hydrophilic characteristics. The reactions on these resins are less time-consuming and less labour-intensive.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to the development of processes for the preparation of a new class of crosslinked polymeric gels of the general structure (I) derived from glycerol/glycerolyl diglycerolate diacrylate/dimethacrylate (II) and vinyl mono- mers (III). These processes involve radical-induced copolymerisation of the monomers III and the crosslinking agents II in various proportions in emulsion, bulk, solution and suspension. The invention also relates to preparation of derivatives of the polymeric gels of the general formula I by chemical modification of the functional groups in them leading to other functional resins finding application in peptide syn- thesis and bioorganic chemistry.

The processes for the conversion of the hydroxyl groups in I to chloro, bromo, amino, 4-bromobenzyl, 3-nitro-4-bromobenzyl and 4-oxybenzylalcohol are also variants included in this invention. The crosslinked polymeric gels of the general formula I are a novel class of macro- molecular gels which are applied in general organic synthesis, peptide synthesis, combinatorial organic synthesis, enzyme immobilization and in biochemical transformations.

Objects of the present invention are all substances of the general formula I and derivatives thereof per se, their manufacture and functionalization with groups prevalent in polymer supported methods of peptide synthesis.

According to the present invention the polymers of the general formula I can be manufactured by radical-induced crosslinking copolymerization of vinyl monomers of the general structure III with glycerol-based divinyl crosslinking agents having the general formula I, wherein R1 , R2 and x have the above described significance. The radical initiator is either dibenzoyl peroxide or azoisobutyronitrile (AIBN). The polymerizations are carried out in suitable emulsions, in suitable solutions of the monomers and crosslinking agents or in bulk.

The processes for the production of polymeric gels according to the present inven- tion are the following:

1 ) Crosslinking copolymerization of styrene with glycerol-1 ,3-diglycerolate diacrylate in emulsion, in solution or in the bulk state initiated by dibenzoyl peroxide or azoisobutyronitrile (AIBN). The feed ratio of the monomers in the copolymeriza- tion mixture varies from 1 to 25% of the difunctional crosslinking agent.

2) Crosslinking copolymerization of acrylamide with glycerol-1 ,3-diglycerolate diacrylate in emulsion, in solution or in the bulk state initiated by dibenzoyl peroxide or azoisobutyronitrile (AIBN). The feed ratio of the monomers in the copolym- erization mixture varies from 1 to 25% of the difunctional crosslinking agent.

3) Crosslinking copolymerization of styrene with glycerol dimethacrylate in emulsion, in solution or in the bulk state initiated by dibenzoyl peroxide or azoisobutyronitrile (AIBN). The feed ratio of the monomers in the copolymerization mix- ture varies from 1 to 25% of the difunctional crosslinking agent.

4) Crosslinking copolymerization of acrylamide with glycerol dimethacrylate in emulsion, in solution or in the bulk state initiated by dibenzoyl peroxide or azoisobutyronitrile (AIBN). The feed ratio of the monomers in the copolymerization mix- ture varies from 1 to 25 % of the difunctional crosslinking agent.

5) Crosslinking copolymerization of styrene with tripropyleneglycol glyceroate diacrylate in emulsion, in solution or in the bulk state initiated by dibenzoyl peroxide or azoisobutyronitrile (AIBN). The feed ratio of the monomers in the copolym- erization mixture varies from 1 to 25% of the difunctional crosslinking agent.

6) Crosslinking copolymerization of acrylamide with tripropyleneglycol glyceroate diacrylate in emulsion, in solution or in the bulk state initiated by dibenzoyl peroxide or azoisobutyronitrile (AIBN). The feed ratio of the monomers in the copolymerization mixture varies from 2 to 25% of the difunctional crosslinking agent.

7) Conversion of the hydroxyl groups in the polymeric gels resulting from the processes 1 to 6 above by treatment with thionyl chloride to give the corresponding chloro functional glycerogels.

8) Conversion of the hydroxyl groups in the polymeric gels resulting from the processes 1 to 6 above by treatment with thionyl bromide to give the correspond- ing bromo functional glycerogels.

9) Conversion of the chloro or bromo functional groups in the gels derived from processes 7 and 8 into amino groups by a polymer-analogous reaction comprising treatment with hexamethylenediamine.

10) Introduction of acid-cleavable bromomethylbenzyl anchoring groups into the amino glycerogels derived from process 9 above by dicyclohexylcarbodiimide- mediated coupling with 4-bromomethylbenzoic acid.

1 1 ) Introduction of photo-cleavable 3-nitro-4-bromomethybenzyl anchoring groups into the amino glycerogels derived from process 9 above by dicyclohexyl- carbodiimide-mediated coupling with 3-nitro-4-bromomethylbenzoic acid.

1 2) Introduction of carboxyl groups in the glycerogels by treatment of the amino glycerogels derived from process 9 by treatment with excess succinic anhydride.

13) Conversion of the 3-nitro-4-bromomethyl benzyl groups in the gels derived from process 1 1 to 3-nitro-4-aminomethylbenzyl groups.

14) Coupling of t-butyloxycarbonyl (Boc) derivatives of the naturally occurring alpha-amino acids to the hydroxyl, chloro, bromo, bromomethylbenzyl and 3-nitro- 4-bromomethylbenzyl functionalized glycerogels. 1 5) Coupling of fluorenymethyloxyoxycarbonyl (Fmoc) derivatives of the naturally occurring alpha-amino acids to the hydroxyl, chloro, bromo, bromomethylbenzyl and 3-nitro-4-bromomethylbenzyl functionalized glycerogels .

The glycerogels of the general formula I and their chemically modified derivatives are a novel class of crosslinked functional polymers for solid-phase organic synthesis, peptide synthesis, combinatorial organic synthesis, enzyme immobilization and biochemical transformations. These glycerogels are biocompatible.

Stepwise peptide syntheses by making use of standard protocols of Boc and Fmoc chemistry are carried out much more efficiently and in much higher yields and purity by making use of the hydrogels of the present invention. The chloromethyla- tion step, which is generally required for the functionalization of the resins in crosslinked polystyrene supported-solid phase peptide synthesis, is avoided in the glycerogels. Methods, which are conventional in peptide and resin chemistry and familiar to any person skilled in the art are applied for carrying out above mentioned processes. Hydrophobic peptides, which cannot be prepared by any other method known so far can be prepared using the glycerogels of the present invention. The hydrophilicity-hydrophobicity balance is adjustable in these gels. This is achieved by a judicious choice of the relative amounts of the monomer and the crosslinking agent in the feed polymerization mixture. The solvent compatibility, extent of swelling in different solvents and the biocompatibility of these resins are dependent on the hydrophilicity-hydrophobicity balance. The reactivity of the functional groups attached to these resins is also very high owing to the extensive swelling in the type of solvents used. According to this invention, the functional group capacity can also be varied at will to suit to the synthetic requirement of the peptide or protein sequence. The capacity can be kept at a higher value, compared to the hitherto existing systems, without negatively affecting the synthetic steps. All the reactions proceed in high speed and in homogeneity and purity (90 to 98%). Peptides are isolated in 25 mg to 5 g range. Segment condensation and chemoselective ligation procedures as applied to solid-phase synthesis are also applicable with these glycerogels. Abbreviations

The following abbreviations are used following the recommendations of the IUPAC- IUB commission on Biochemical Nomenclature, Biochem. J. 1984, 21 9, 31 5; Eur. J. Biochem. 1984, 1 38, 9.

AIBN Azoisobutyronitrile

AcOH Acetic acid

Acr₂ PEG Bis-2-acrylamidoprop-l-yl polyethyleneglycol

Boc Butyloxycarbonyl

Bz₂0₂ Benzoyl peroxide

CMME Chloromethyl ether

DCM Dichloromethane

DIEA N,N'-Diisopropylethylamine

DMA Dimethylacetamide

DMAP Dimethylaminopyridine

DMF Dimethylformamide

DMSO Dimethylsulfoxide

DVB Divinylbenzene

EtOH Ethanol

Fmoc 9-Fluorenylmethyloxycarbonyl

HBTU 2-( 1 H-Benzotriazol-1 -yl) 1 , 1 ,3,3-tetramethyluronium hexafluorophosphate

HCV Hepatitis C virus

HMBA 4-Hydroxymethylbenzoic acid

HMPB 4-(4-Hydroxymethyl-3-methoxyphenoxy) butyric acid

HOBt 1 -Hydroxybenzotriazole

HPLC High performance liquid chromatography

IR Infrared

MeCN Acetonitrile

MALDI-MS Matrix-Assisted Laser Desorption lonization Mass

Spectrometry

MeOH Methanol Mmol Millimole

Mtr 4-Methoxy-2,3,6-trimethylbenzenesulphonyl

(NH₂)₂ PEG Bis-2-aminoprop-l-yl polyethyleneglycol

NMP N-methylpyrrolidone

NMR Nuclear magnetic resonance

OtBu t-Butylester

PEG Polyethyleneglycol

PEGA Polyethyleneglycol polyacrylamide copolymer

PS Polystyrene

PVA Polyvinylalcohol

Tbu t-Butyl

TEA Triethylamine

TEMED Tetramethylethylenediamine

TFA Trifluoroacetic acid

THF Tetrahydrofuran

TLC Thin layer chromatography

Trt Trityl (triphenylmethyl)

TTEGDA Tetraethyleneglycol diacrylate

EXAMPLES OF GLYCEROGEL (I) AND ITS ANALOGUES

The following examples are provided by way of illustration and not by way of limitation of aspects of the present invention.

Example 1

Preparation of Glycerogel 1 : Glycerol-1 ,3diglycerolate diacrylate-Crosslinked Polystyrene

Styrene and glycerol-1 ,3-diglycerolate diacrylate were washed with 1 % NaOH solution and then with distilled water to remove the inhibitors and dried over anhydrous Na₂S0₄. A four-necked reaction vessel equipped with a thermostat, teflon stirrer, water condenser and nitrogen inlet and a dropping funnel was used for the polymerization. A 1 % solution of poly(vinyl alcohol) (MW^"75 000) was prepared by dissolving PVA (1 .1 g)in double distilled water(1 10 ml) at 80 °C. A mixture of styrene (10.4 g), glycerol-1 ,3-diglycerolate diacrylate (1 .1 g) and benzoyl peroxide (0.5 g) dissolved in toluene (10 ml) were added to PVA solution by stirring the aqueous solution at 2000 rpm. A slow stream of nitrogen was bubbled into the reaction mixture. The temperature of the reaction mixture was maintained at 80 °C using a thermostated oil bath and the reaction is allowed to continue for 6 hrs. The solvent embedded copolymer beads were washed free of stabilizer and the unreacted monomers by treating with hot distilled water, acetone, DCM and methanol. The polymer beads were dried under vacuum at 40 °C for 10 hrs. Yield: 8.4 g. Capacity: 0.65 mmol OH/g.

Example 2

Glycerogel 2: Glyceroldimethacrylate (GMDA)-Crosslinked Polystyrene Gel Inhibitors were removed from styrene and glyceroldimethacrylate by washing with 1 % NaOH solution and distilled water. A four-necked reaction vessel equipped with a thermostat, Teflon stirrer, water condenser and nitrogen inlet was used for the polymerization reaction. Polyvinylalcohol (MW: 75000, 1 J g) was dissolved in double distilled water ( 1 10 ml). This was added to the reaction vessel. Bubbling nitrogen gas through it for 30 min deoxygenated the solution. The monomers styrene (10.2 g) and glyceroldimethacrylate (0.45 g) were dissolved in toluene (10 ml) and this was added to the reaction vessel. The mixture was stirred at a rate of 2000 rpm. Benzoyl peroxide (800 mg) was added and the reaction vessel was sealed with a water condenser on one side and a rubber septum on the other. The polymerization_^ mixture was heated at 80°C using a thermostated oil bath while maintaining a continuous flow of nitrogen gas through the reaction media. The polymerization was allowed to continue for 6hrs. Boiled water (300 ml) was then added to the reaction mixture and stirred for another 30 min. The polymer beads were collected by filtration, washed further with hot water (5 x 100 ml), acetone (5 x 50 ml), toluene (5 x 50 ml) and methanol (5 x 50 ml). The polymer beads were soxhlet extracted with dichlormethane and methanol and dried under vacuum for 8 hrs. Yield of gel beads: 10.3 g. Example 3

Glycerogel 3: Tripropyleneglycol Glycerol Glycerolate Diacrylate-Crosslinked Polystyrene Gel Styrene and tripropyleneglycol glycerol glycerolate diacrylate (TPGDA) were washed with 1 % NaOH solution and then with distilled water to remove the inhibitors and dried over anhydrous Na₂S0₄. A four-necked reaction vessel equipped with a thermostat, teflon stirrer, water condenser and nitrogen inlet and a dropping funnel was used for the polymerization. A 1 % solution of poly(vinyl alcohol) (MW~75 000) was prepared by dissolving PVA (1 .1 g) in double distilled water (1 10 ml) at 80 °C. A mixture of styrene (10.4 g), TPGDA (1.0 g) and benzoyl peroxide (0.8 g) dissolved in toluene (10 ml) were added to PVA solution by stirring the aqueous solution at 2000 rpm. A slow stream of nitrogen was bubbled into the reaction mixture. The temperature of the reaction mixture was maintained at 80 °C using a thermo- stated oil bath and the reaction was allowed to continue for 6 hrs. The solvent embedded copolymer beads were washed free of stabilizer and the unreacted monomers by treatment with hot distilled water, acetone, DCM and methanol. The polymer beads were dried under vacuum at 40 °C for 8 hrs. Yield: 9.4 g.

Example 4

Glycerogel 4: Glycerol-1 ,3diglycerolate diacrylate-crosslinked Polyacrylamide Gel

Glycerol-1 ,3-diglycerolate diacrylate was washed with 1 % NaOH solution and then with distilled water to remove the inhibitor and dried over anhydrous Na₂S0₄. A four-necked reaction vessel equipped with a thermostat, teflon stirrer, water condenser and nitrogen inlet and a dropping funnel was used for the polymerization. A 1 % solution of poly(vinyl alcohol) (MW^"75 000) was prepared by dissolving PVA (1 .1 g) in double distilled water (1 10 ml) at 80 ° C. A mixture of acrylamide (10.4 g in 100 ml water), glycerol-1 ,3-diglycerolate diacrylate (1 .1 g) and azoisobutyronitrile (AIBN, 0.5 g) dissolved in toluene (10 ml) were added to PVA solution by stirring the aqueous solution at 2000 rpm. A slow stream of nitrogen was bubbled into the reaction mixture. The temperature of the reaction mixture was maintained at 80 °C using a thermostated oil bath and the reaction was allowed to continue for 6 hrs. The solvent embedded copolymer beads were washed free of stabilizer and the unreacted monomers by treating with hot distilled water, acetone, DCM and methanol. The polymer beads were dried under vacuum at 40 ° C for 10 hrs. Yield: 9.7g.

Example 5

Glycerogel 5: Glyceroldimethacrylate (GMDA)-crosslinked Polyacryl-amide Gel

Glyceroldimethacrylate was washed with 1 % NaOH solution and distilled water. A four-necked reaction vessel equipped with a thermostat, Teflon stirrer, water con- denser and nitrogen inlet was used for the polymerization. Polyvinylalcohol (MW: 75000, 1 .1 g) was dissolved in double distilled water (1 10 ml) and was added ^'to the reaction vessel. Acrylamide (1 1 .4 g) taken in 100 ml water was kept in the reaction vessel deoxygenated the solution, bubbling nitrogen gas through it for 30 min. Glyceroldimethacrylate (0.45 g) was dissolved in toluene (10 ml) and was added to it. The polymerization mixture was stirred at a rate of 2000 rpm. Azoisobutyronitrile (AIBN, 900 mg) was added and the reaction vessel was sealed with a water condenser on one side and a rubber septum on the other. The polymerization mixture was heated at 80 °C using a thermostated oil bath while maintaining a continuous flow of nitrogen gas through the reaction media. The polymerization was allowed to continue for 6 hrs. Thereafter, boiled water (300 ml) was added to the reaction mixture and stirred for another 30 min. The polymer beads were collected by filtration, washed further with hot water (5 x 100 ml), acetone (5 x 50 ml), toluene (5 x 50 ml) and methanol (5 x 50 ml). The polymer beads were sox- hlet extracted with dichlormethane and methanol and dried under vacuum for 8 hrs. Yield of the gel beads: 9.3 g.

Example 6

Glycerogel 6: Tripropyleneglycol Glycerol Glycerolate Diacrylate-Crosslinked Poly- acrylamide Gel

Tripropyleneglycol glycerol glycerolate diacrylate (TPGDA) was washed with 1 % NaOH solution and then with distilled water to remove the inhibitor and dried over anhydrous Na₂S0₄. A four-necked reaction vessel equipped with a thermostat, teflon stirrer, water condenser and nitrogen inlet and a dropping funnel was used for the polymerization. A 1 % solution of poly(vinyl alcohol) (MW^"75 000) was prepared by dissolving PVA (1 J g) in double distilled water (1 10 ml) at 80 °C. This was added to the reaction vessel. Acrylamide (1 1 .4 g) taken in 100 ml water was kept in the reaction vessel, bubbling nitrogen gas through it for 30 min. deoxygenated the solution. TPGDA (0.90 g) was dissolved in toluene (10 ml) and this was added to it. The polymerization mixture was stirred at a rate of 2000 rpm. Azoisobutyronitrile (AIBN, 900 mg) was added and the reaction vessel was sealed with a water condenser on one side and a rubber septum on the other. The polymeriza- tion mixture was heated at 80°C using a thermostated oil bath while maintaining a continuous flow of nitrogen gas through the reaction media. The polymerization was allowed to continue for 6 hrs. Boiled water (300 ml) was then added to the reaction mixture and stirred for another 30 min. The polymer beads were collected by filtration, washed further with hot water (5 x 100 ml), acetone (5 x 50 ml), toluene (5 x 50 ml) and methanol (5 x 50 ml). The polymer beads were soxhlet extracted with dichloromethane and methanol and dried under vacuum for 8 hrs. Yield of gel beads: 8.9 g.

Example 7

Chloroglycerolgel 1 : Chlorination of Glycerogel 1 with Thionyl Chloride

Glycerogel 1 (3 g, 1 .95 mmol OH) suspended in dichlormethane (80 ml) was stirred with thionyl chloride (10 ml) under nitrogen atmosphere and under ice-cooling for 1 2 hrs. The reaction mixture was then filtered, washed successively with di- chloromethane, acetone, water acetone and dried under vacuum for 3 hrs. Yield of chloroglycerogel 1 : 3.2 g. Chlorine capacity: 0.32 mequiv/g.

Example 8

Chloroglycerolgel 2: Chlorination of Glycerogel 2 with Thionyl Chloride

Glycerogel 1 (3 g, 3.6 mmol OH) suspended in dichlormethane (80 ml) was stirred with thionyl chloride (1 2 ml) under nitrogen atmosphere and under ice-cooling for 1 2 hrs. The reaction mixture was then filtered, washed successively with di- chloromethane, acetone, water acetone and dried under vacuum for 3 hrs. Yield of chloroglycerogel 1 : 3.8 g. Chlorine capacity: 1 .1 mequiv/g.

Example 9

Chloroglycerolgel 3: Chlorination of Glycerogel 3 with Thionyl Chloride

Glycerogel 3 (3 g, 1 .65 mmol OH) suspended in dichlormethane (80 ml) was stirred with thionyl chloride (10 ml) under nitrogen atmosphere and under ice-cooling for 1 2 hrs. The reaction mixture was then filtered, washed successively with di- chloromethane, acetone, water acetone and dried under vacuum for 3 hrs. Yield of chloroglycerogel 1 : 3.3 g. Chlorine capacity: 0.42 mequiv/g.

Example 10

Bromoglycerogel 1 : Bromination of Glycerogel 1 with Thionyl Bromide

Glycerogel 1 (3 g, 1 .95 mmol OH) suspended in dichlormethane (80 ml) was stirred with thionyl bromide (8 ml) under nitrogen atmosphere and under ice-cooling for 1 2 hrs. The reaction mixture was then filtered, washed successively with di- chloromethane, acetone, water acetone and dried under vacuum for 3 hrs. Yield of bromoglycerogel 1 : 3.3 g. Bromine capacity: 0.51 mequiv/g

Example 1 1

Bromoglycerogel 2: Bromination of Glycerogel 2 with Thionyl Bromide Glycerogel 2 (3 g, 3.6 mmol OH) suspended in dichlormethane (80 ml) was stirred with thionyl bromide (8 ml) under nitrogen atmosphere and under ice-cooling for 1 2 hrs. The reaction mixture was then filtered, washed successively with di- chloromethane, acetone, water acetone and dried under vacuum for 3 hrs. Yield of bromoglycerogel 2: 3.8 g. Bromine capacity: 1 .1 mequiv/g Example 12

Bromoglycerogel 3: Bromination of Glycerogel 3 with Thionyl Bromide

Glycerogel 3 (3 g, 1 .65 mmol OH) suspended in dichlormethane (80 ml) was stirred with thionyl bromide (8 ml) under nitrogen atmosphere and under ice-cooling for 1 2 hrs. The reaction mixture was then filtered, washed successively with di- chloromethane, acetone, water acetone and dried under vacuum for 3 hrs. Yield of bromoglycerogel 3: 3.2 g. Bromine capacity: 0.62 mequiv/g

Example 13

Aminoglycerogel 1 : Treatment of Bromoglycerogel 1 with Hexamethylenetetramine

Bromoglycerogel 1 (2 g, 1 .02 mmol Br) suspended in DMF was stirred with^' hexamethylenetetramine (3 g) at 70 °C for 6 hrs. The resin beads were filtered, washed with DMF, dichloromethane and methanol. Dried under vacuum. Yield: 1 .3 g; amino capacity: 0.45 mequiv/g.

Example 14

Aminoglycerogel 2 by the Transamidation of Glyceropolyacrylamide Gel 4 with Excess Ethylenediamine

Glycerogel 4 (5 g) suspended in DMF (50 ml) was stirred with ethylenediamine ( 10 ml) at 80 °C for 3 hrs. The reaction mixture was added to ice-cold water, washed with water, DMF and methanol. Dried under vacuum. Yield of the aminoglycerogel 2: 6.2 g; amino capacity: 4.2 mmol/g.

Example 15

Carboxyl Functionalized Glycerogel Aminoglycerogel 1 (1 g, 0.45 mequiv) suspended in methylenechloride (20 ml) was stirred with succinic anhydride (500 mg) at 70 °C under nitrogen atmosphere for 4 hrs. The reaction mixture was filtered, washed with hot water and methanol. The polymer beads were dried under vacuum. Yield: 1 .1 g; Carboxyl capacity: 0.31 mequiv. /g.

Example 16

4-BromomethyIbenzamido Glycerogel: Acid-Cleavable Glycerogel Support for Peptide Synthesis

4-Bromomethylbenzoic acid (0.54 g, 2.5 mmol) and HOBt (6.6g, 5 mmol) were dissolved in dichloromethane (50 ml). 4.95 g of DCC in 25 ml dichloromethane was added to this and stirred at room temperatureJor 1 hr. The precipitated dicy- clohexyl urea was filtered off and the HOBt active ester was shaken with a suspension of the aminoglycerogel (500 mg) in dichloromethane (10 ml). After, 1 hr the resin was filtered, washed with DCM, DMF and MeOH (4 x 15 ml each) and dried under vacuum. Yield: 520 mg; bromine content: 0.28 mequiv/g.

Example 17

3-Nitro-4-bromomethylbenzamido Glycerogel: Photocleavable Glycerogel for Peptide Synthesis 3-Nitro-4-bromomethylbenzoic acid (2.09 g, 0.8 mmol) and HOBt (2J 6 g, 1 .6 mmol) were dissolved in DCM (25 ml). A solution of DCC ( 1 .65 g, 0.8 mmol) in DCM (1 5 ml) was added and stirred at 0°C for 30 min and then at room temperature for 1 hr. The DCU was filtered off and the HOBt ester formed was shaken with aminglycerogel (500 mg). After 1 hr, the resin was filtered, washed with DCM, DMF and MeOH. The resin was dried to constant weight. Bromine capacity: 0.27 mequiv./g. IR/KBr): 1 650, 1 340, 1 540 cm-1 .

Example 18

4-Hydroxymethyl Phenoxyacetamidomethyl Glycerogel

Hydroxymethylphenoxyacetic acid (364 mg, 2 mmol), HBTU (794 mg, 2 mmol), HOBt (270 mg, 2 mmol), DIEA (250 μl, 2 mmol) were added to the pre-swollen aminoglycerogel (1 g), in DMF and the reaction mixture was kept at room tempera- ture for 1 hr with shaking. The quantitative conversion was ascertained by ninhy- drin test. The resin was filtered and washed with DMF (3 x 30 ml), dioxane/H₂0 (1 : 1 , 3 x 30 ml), MeOH (3 x 30 ml) and ether (3 x 30 ml). The resin was collected and dried in vacuum. Hydroxyl capacity = 0.66 mmol/g.

APPLICATIONS IN PEPTIDE SYNTHESIS

Example 19

Synthesis of Acyl Carrier Protein Fragment (65-74) Using Glycerogel 1 Support

Attachment of C-terminal Fmoc-Gly to Glycerogel 1 : The resin (100 mg) was allowed to swell in DMF (5 ml) for 1 hr. Excess DMF was removed by filtration. Fmoc-Gly-Opfp ester (463 mg) was added to the resin and shaken at room tem- perature. After 1 hr, the resin was filtered and washed with DMF, DCM ether and dried under vacuum. The extent of attachment of the amino acid was estimated by adding 20% piperidine in DMF (3 ml) to the pre-weighed resin (5 mg). After 30 min. the optical density of the solution was measured at 290 nm. From the OD the amino capacity of the resin was calculated: Amino capacity: 0.25 mmol/g.

Synthesis of ACP (65-74): Val-Gln-Ala-Ala-lle-Asp-Tyr-lle-Asn-Gly

The Fmoc-Gly glycerogel resin was allowed to swell in DMF for 1 hr. All the Fmoc amino acids as required in the sequence were stepwise coupled to the resin by the HOBt active ester method. In a typical coupling step, HOBt (8.4 mg, 0.062 mmol) and HBTU (26.6 mg, 0.062 mmol) were added to the Fmoc-amino acid (2.5 mmol) dissolved in DMF ( 1 ml). The solution was added to the resin and kept shaken for 50 min. The extent of coupling was monitored by ninhydrin test. A single coupling was required for the quantitative incorporation of each amino acid unit. Fmoc protection was removed by 20 % piperidine in DMF. After each coupling and depro- tection step, the resin was washed with DMF, methanol and ether successively. Removal of the Peptide from the Polymer Support

The peptidyl resin was suspended in a mixture of TFA (2.55 ml), thioanisole, ethanedithiol and double distilled water (150 ml each). The reaction was allowed to continue for 8 hrs. The cleaved resin was filtered, and washed with fresh TFA and then rinsed with DCM. The filtrate was evaporated under vacuum to give a thick oily residue. Addition of ice-cold ether precipitated the peptide as a white powder, which was then washed thoroughly with ether and dried. Yield of peptide: 24 mg (92%).

Comparison with Merrifield and Sheppard Resins

The efficiency of the new support was established by comparing the purity of the 65-74 fragment of the acyl carrier protein synthesized on glycerolgel 1 , PS-DVB and Sheppard resins under identical synthetic conditions. 4- Hydroxymethylphenoxyacetic acid handle (HMPA) was attached to the amino methyl resin by using HBTU, HOBt and DIEA. PS-DVB, Sheppard and polystyrene resins attached with HMPA handle were used for the synthesis. The respective resins were taken in 0.01 mmol scales. C-terminal Fmoc-Gly was attached to the respective resins by an ester bond using MSNT in presence of N-methyl imidazole. The extent of attachment was measured from the UV absorbance of the adduct of dibenzofulvene and piperidine formed by the treatment of accurately weighed Fmoc-amino acid attached resin with 20% piperidine in DMF. After removing the Fmoc-protection with 20% piperidine in DMF, the remaining Fmoc-amino acids were coupled by using 3 equivalents of HBTU, HOBt and DIEA. In a particular coupling reaction_^amino acids and coupling reagent required for three resins were cal- culated, weighed and dissolved in a definite volume of DMF, this solution was distributed equally in the respective resins, and the coupling reaction was continued for 30 min. The peptide was cleaved from the resin using TFA in presence of scavengers. The new glycerogel 1 support yielded 24 mg, Merrifield resin yielded 1 6 mg and Sheppard resin yielded 1 9 mg crude peptide. The peptide from the glyc- erogel resin showed a sharp single major peak in the HPLC whereas that from Merrifield resin showed several peaks. The comparative study indicates that the glycerol gels are much more efficient in peptide synthesis. This is a further advantage in addition to the easy preparation of the glycerol gels in one-step high-yielding polymerization reaction.

Amino acid analysis of peptide from the new glycerol gel 1 resin: Val, 0.98 (1 ); lie, 2J (2); Tyr, 0.89 (1 ) Asp, 1 .92 (2); Ala, 2.1 (2); Glu, 0.93 (1 ); Gly, 0.98 (1 ). Asn and Gin are hydrolyzed to Asp and Glu.

MALDI TOF MS: m/z 1046.3 [(M + H) ⁺ , 100%], C₄₇H₇₄N₁₂0₁₆, requires M ⁺ 1045.1 2.

Swelling studies

The solvent absorption of various resins was determined by a centrifuge method. The resin (1 g) was placed in a glass-sintered stick (G3) and the latter was immersed in the solvent for 48 hrs. The stick was then transferred to a centrifuge tube and the excess solvent was removed by centrifuging for 15 min. The stick and the contents were then weighed. A similar blank experiment was performed using an empty sintered stick. The data was expressed as the volume of t^k~ solvent absor>^ by unit weight of dry resin (ml/g). In another experiment the volume occupied by unit weight of dry resin in its solvent swollen state (ml/g) was measured by noting the volume resulting when a defi- nite weight of dry resin was added to a known volume of solvent in a small measuring cylinder.

Stability studies

The stability studies of the resin were carried out in different reagents such as 100% TFA (10 ml), 20% piperidine in DMF (10 ml), 2 M aqueous NaOH (10 ml), 2 M NH₂OH in aqueous methanol (10 ml) and liquor ammonia (10 ml). 100 mg of each resin sample was separately stirred with the above reagents. After 48 hrs the resin samples were filtered, washed thoroughly with ethanol (3 x 50 ml), water (3 x 50 ml), acetone (3 x 50 ml), DCM (3 x 50 ml), dioxane (3 x 50 ml) and ether (3 x 50 ml), dried, weighed (100 mg) and the IR (KBr) spectra of these resins were compared with the original. Estimation of Chlorine in Chloroglycerogels

Halogenated PS-TGDMA resin (50 mg) was treated with pyridine (5 ml) in a Kjeldahl flask for 6 hrs at 100-1 10 °C. The resin was removed by filtration, washed with acetic acid/water (1 : 1 , 30 ml). The filtrate and the washings were acidified with cone. HN0₃ (5 ml). A saturated solution of AgN0₃ (0J N, 5 ml) was added to the mixture and stirred well. The excess AgN0₃ was determined by back titration with standard ammonium thiocyanate solution (0J N) using ferric aluminium as indicator (modified Voihardt's method). A blank was also performed and the halogen capacity was calculated from the titer values.

Estimation of Hydroxyl Capacity

The resin (200 mg) was acetylated with a measured amount of acetic anhydride- piperidine mixture (1 : 4, 3 ml) for 6 hrs. 10 ml distilled water was added and the mix was refluxed for 3 hrs and then cooled and filtered. Acetic acid formed was back titrated with standard (0J N) NaOH. Capacity was observed as 0.69 mmol/g.

Estimation of the Amino Group: Picric Acid Method:

The amino resin (2 mg) was taken a sintered Gisin's tube and treated with 0.1 M picric acid (2 x 5 ml x 5 min). The resin was washed thoroughly with DCM to re- move the unbound picric acid. The resin bound picric acid was eluted with 5% DIEA in DCM till the eluate was clear. The eluate was made up to a definite volume (1 5 ml) using 95 % ethanol. A definite volume of this solution (0.5 ml) was diluted to 5 ml with 95% ethanol. The optical density of this solution was measured at 358 nm. The substitution level of the first amino acid can be calculated from the OD value, weight of the resin taken and the extinction coefficient of picrate (e₃₅₈ = 14,500). Amino capacity = 0.69 mmol/g.

C-Terminal Boc-AA Incorporation in Glycerogels: General Procedure

The following procedure is typical of C-terminal attachment of Boc-amino acids to hy- droxyl functionalized glycerogels. Boc-Asp(OBzl)OH (32.35 mg, 0.1 mmol) was dissolved in DCM (10 ml). DCC (10.3 mg, 0.05 mmol) in DCM (10 ml) was added to the mixture and stirred at 0 °C for 30 min. and for a further 30 min. duration at room temperature. The DCU was filtered off. The filtrate was evaporated under vacuum to yield the anhydride. The glycerogel resin (equivalent to 0.05 mmol OH) was allowed to swell in DMF or DCM for 1 hr. The BocAAanhydride and DMAP (5 mg, 0.04 mmol) dissolved in DMF (1 ml) was added to the resin and the mixture was shaken for 1 hr. The resin was filtered, washed with DMF (3 x 50 ml), isoamylalcohol (3 x 50 ml), acetic acid (3 x 50 ml), ether (3 x 50 ml) and dried under vacuum. The capacity of the resin was estimated by the picric acid method as described above. Capacity: 0.096 mmol Asp/g.

Preparation of PS-GDMA-HMPA Resin

4-HydroxymethyIphenoxyacetic acid (364 mg, 2 mmol), HBTU (794 mg, 2 mmol), HOBt (270 mg, 2 mmol), DIEA (250 μl, 2 mmol) were added to pre-swollen amino glycerogel (1 g, 0.69 mmol) in DMF and the reaction mixture was kept at room temperature for 1 hr with occasional shaking. The quantitative conversion was estimated by ninhydrin test. The resin was filtered and washed with DMF (3 x 30 ml), dioxane/H₂0 (1 : 1 , 3 x 30 ml), MeOH (3 x 30 ml) and ether (3 x 30 ml). The resin was collected and dried under vacuum. Hydroxyl capacity = 0.66 mmol/g. IR(KBr): 3400 cm^"1 (NH), 3380 cm^"1 (OH), 1 643 cm^"1 (NHCO).

EXAMPLES OF PEPTIDES SYNTHESISED AND THEIR YIELDS

(Single HPLC peak after one purification, isolated amounts ranging from 50 mg to 5 g, depending upon the capacity of the resin)

1 . Boc-NH-Gly-lle-Cys(Acm)-Pro-OH( 90%)

2. Fmoc-NH-Leu-Asp(0-t-Bu)-Leu-Gly-Ala-Gly-OH (93%)

3. Ile-Ala-Val-Gly-NH₂ (91 %) 4. Boc-NH-Pro-Val-NH₂ (95%)

5. Boc-NH-Leu-Ala-Val-NHMe (90%)

6. Boc-NH-Val-Leu-Ala-Val-NHEt (95%)

7. H-Leu-Ile-Asn-Thr-Asn-Ala-Ser-Trp-His-Ala-Asn-Arg-Thr-8. Ala-Leu-Ser- Asn-Asp-Ser-Lys-Leu-Asn-Thr-Gly-Ala-NH₂ (90%) 9. H-Leu-Asn-Cys(Acm)-Asn-Asp-Ser-Leu-Asn-Thr-AI-NH₂ (92%) Immobilization of Enzymes on Aminoglycerogels

Carboxyl functionalized glycerogel from example 1 5 (100 mg) was treated with N- hydroxysuccinimide ( 1 55 mg) and DCC (103 mg) in dichloromethane (25 ml). The mixture was stirred at 0 °C for 1 hr and then at room temperature for 5 hrs. The resin was filtered and washed with THF and then with DCM. The resin was then added to a solution of chymotrypsin in pH 7 phosphate buffer. The reaction mixture was kept stirring at 0 °C for 1 hr, then filtered, washed with water and methanol, and dried under vacuum. The resulting immobilized chymotrypsin retained 57 % of the original activity.

The foregoing typical results illustrate the various applications of glycerogels, a novel class of crosslinked polymeric gels, which can be easily prepared using specific polymerization techniques.

Claims

1 . A process for the preparation of polymeric gels for solid phase synthesis comprising radical-induced copolymerization of monomeric molecules and bifunc- tional crosslinking agents, wherein said monomeric molecules and crosslinking agents are added in ratios providing said polymeric gels with a hydrophilic or hydrophobic balance depending on a respective substrate.

2. The process according to claim 1 , wherein the monomeric molecules are vinyl monomers of the general formula III

(III) R1 = Ph; CONH₂

with R, being Ph or CONH₂; the crosslinking agents are glycerol-based divinyl of the general formula II,

(II) R2 = H; Me

with R₂ being H or Me; and the polymeric gels are of the general formula I

x = 2, 5, 10, 15, 20, 25 (I) R¹ = Ph; CONH₂ R² = H; Me

with x being 2, 5, 10, 1 5, 20 or 25, R, being Ph or CONH₂, and R₂ being H or Me.

3. The process according to claims 1 -2, wherein the monomer styrene is copolymerized with the crosslinking agent glycerol-1 .3-diglyceroate diacrylate.

4. The process according to claims 1 -2, wherein the monomer acrylamide is copolymerized with the crosslinking agent glycerol-1 .3-diglyceroate diacrylate.

5. The process according to claims 1 -2, wherein the monomer styrene is copolymerized with the crosslinking agent glycerol dimethacrylate.

6. The process according to claims 1 -2, wherein acrylamide as the monomer is copolymerized with the crosslinking agent glycerol dimethacrylate.

7. The process according to claims 1 -2, wherein styrene as the monomer is copolymerized with the crosslinking agent tripropyleneglycol glyceroate diacrylate.

8. The process according to claims 1 -2, wherein acrylamide as the monomer is copolymerized with the crosslinking agent tripropyleneglycol glyceroate diacrylate.

10. The process according to anyone of the preceeding claims, wherein the co- polymerisation is induced by a radical initiator selected from the group comprising dibenzoyl peroxide and azoisobutyronitrile (AIBN).

1 1 . The process according to anyone of the preceeding claims, wherein the feed ratio of said monomers in the reaction mixture varies from 1 to 25% of the bifunc- tional crosslinking agent.

1 2. The process according to anyone of the preceeding claims, wherein the crosslinking copolymerization takes place in emulsion, in solution or in a bulk state.

13. A process for the conversion of the hydroxyl groups in the polymeric gels derived from claims 3-9 into further functional groups, wherein the hydroxyl groups of the respective gels are replaced by bromo, chloro, amino, bromobenzyl, 3- nitrobenzyl or 4-oxybenzylalcohol.

14. The process according to claim 13, comprising the conversion of the hydroxyl groups in the polymeric gels derived from the processes of claims 3-9, by treatment of said gels with thionyl chloride or thionyl bromide.

1 5. The process according to claim 13, comprising the conversion of the bromo or chloro functional groups of the polymeric gels derived from the process of claim

14 into amino groups by a polymer-analogous reaction comprising treatment with hexamethylenediamine.

1 6. The process according to claim 1 3, comprising the introduction of acid- cleavable bromomethylbenzyl anchoring groups into the amino glycerogels derived from the process of claim 1 5 by dicyclohexylcarbodiimide-mediated coupling with 3-nitro-4-bromomethylbenzoic acid.

17. The process according to claim 13, comprising the introduction of photo- cleavable 3-nitro-4-bromomethylbenzyl anchoring groups into the amino glycerogels derived from the process of claim 1 5 by dicyclohexylcarbodiimide-mediated coupling with 3-nitro-4-bromomethylbenzoic acid.

18. The process according to claim 13, comprising the introduction of carboxyl groups into the glycerogels by treatment of the amino glycerogels derived from the process of claim 1 5 with excess succinic anhydride.

1 9. The process according to claim 13, comprising the conversion of the 3- nitro-4-bromomethylbenzyI groups in the gels derived from the process of claim 1 7 into 3-nitro-4-aminomethylbenzyl groups.

20. Use of the polymeric gels according to anyone of the preceeding claims for organic synthesis, peptide synthesis, combinatorial organic synthesis, enzyme immobilization, biochemical transformations or bioorganic chemistry.

21 . Use according to claim 20 for coupling of t-butyloxycarbonyl (Boc) derivatives of naturally occurring alpha amino acids to the respective functional groups of said polymeric gels.

22. Use according to claim 20 for coupling of fluorenmethyloxyoxycarbonyl (Fmoc) derivatives of naturally occurring alpha amino acids to the functionalized groups of said polymeric gels.

23. The polymeric gels derived from the processes according to claims 1 -1 9. AMENDED CLAIMS

[received by the International Bureau on 14 May 2001 (14.05.01); original claims 1 and 2 amended; remaining claims unchanged (2 pages)]

1. A process for the preparation of polymeric gels for solid phase synthesis comprising radical-induced copolymerization of monomeric molecules and bifunctional crosslinking agents, wherein said monomeric molecules and crosslinking agents are added in ratios providing said polymeric gels with a hydrophilic or hydrophobic balance depending on a respective substrate, characterized in that the monomeric molecules are vinyl monomers and the cross linking agents are glycerol-based divinyl.

2. The process according to claim 1, wherein the vinyl monomers are of the general formula III

(III) R¹ = Ph; CONH₂

with Ri being Ph or CONH₂; the glycerol-based divinyl is of the general formula II,

(II) R2 = H; Me with R₂ being H or Me; and the polymeric gels are of the general formula I

χ=2,5, 10, 15,20, 25

(I) Ri = Ph; CONH₂ R2 = H; Me

with x being 2, 5, 10, 15, 20 or 25, Ri being Ph or CONH₂ and R₂ being H or Me.

3. The process according to claims 1-2, wherein the mono- mer styrene is copolymerized with the crosslinking agent glycerol-1.3-diglyceroate diacrylate .

4. The process according to claims 1-2, wherein the monomer acrylamide is copolymerized with the crosslinking agent glycerol-1.3-diglyceroate diacrylate.

5. The process according to claims 1-2, wherein the monomer styrene is copolymerized with the crosslinking agent glycerol dimethacrylate.

6. The process according to claims 1-2, wherein acrylamide as the monomer is copolymerized with the crosslinking agent glycerol dimethacrylate.