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TITLE
CERTIFICATE
DECLARATION
ACKNOWLEDGEMENT
CONTENTS
GLOSSARY
I. INTRODUCTION AND SCOPE.
Organization of the Thesis
II. CHARACTERISTIC FEATURES OF SOLID-PHASE REACTIONS USING POLYMERIC REAGENTS.
1. Polymeric Acylating Reagents.
a. Polymeric Active Esters.
b. Polymer-Bound Mixed Anhydrides.
c. Polymer-Bound Thiol Esters.
d. The Mediator Methodology.
e. Limitations of the Polymeric Reagent Method of Peptide Synthesis.
2. Polymer Effects in Polymer-Supported Reactions.
a. The Porous Structure of Cross linked Polymers,
b. Site Isolation and Site-Site Interactions.
c. Steric Effects and Spacer Effects.
d. Diffusional and Molecular Sieving Effects.
e. Microenvironmental Effects.
f. Role of Solvent.
g. Effect of Molecular Character and Extent of Cross linking
III. SOLID-PHASE ACYLATION REACTIONS USING POLYMER SUPPORTED MIXED CARBOXYLIC DITHIOCARBAZIC ANHYDRIDES.
Results and Discussion
1. Preparation and Characterization of Polymer-Bound Mixed Carboxylic Dithiocarbazic Anhydrides.
Table III.I Analytical Details of Mixed Carboxylic Dithiocarbazic Anhydride Resins 4c, 4d and 4e
2. Acylation Reactions using Mixed Carboxylic Dithiocarbazic Anhydride Resins.
Table III.2 Benzoylation Reactions using Polymer-Bound Mixed Benzoic Dithiocarbazic Anhydride
Table III.3 p-Nitrobenzoylation using Pqlymer-Bound mixed p-Nitrobenzoic Dithiocarbazic Anhydride
Table III.4 Acetylation Reactions using Polymer-Bound Mixed Acetic Dithiocarbazic Anhydride
3. Recycling of the Spent Reagent Resin.
4. Effect of Molecular Character and Extent of Cross linking on the Reactivity of Cross linked Polystyrene-Bound Mixed Benzoic Dithiocarbazic Anhydrides.
a. Preparation of Polystyrene Cross linked with DVB, HDODA, TTEGDA and TEGDMA.
Table III.5 Details of the Preparation of Crosslinked Polystyrene 7a-7e, 8a-8e. & 10
b. Swelling Characteristics of the Cross linked Polystyrene Resins.
Table III.6 Swelling Capacities of Polystyrene Crosslinked with 2 % DVB, HDODA, TTEGDA and TEGDMA (7a, 8a, 9 and 10)
Table III.7 Swelling Capacities of DVB- Crosslinked Polystyrene Resins
Table III.8 Swelling Capacities of HDODA Crosslinked Polystyrene
c. Chloromethylation of Cross linked Polystyrene Resins.
Table III.9 Chlorine Capacities of Chloromethylated DVB-Crosslinked Polystyrene Resins
Table III.10 Chlorine Capacities of Chloromethylated HDODA _ Crosslinked Polystyrene Resins (12a - 12e)
Table III.11 Chlorine Capacities of Chloromethylated 2%Crosslinked Polystyrene Resins with DVB, HDODA, TTEGDA, and TEGDMA as Crosslinking Agents (11a, 12a, 13 and 14)
d. Conversion of Chloromethyl Resins to Hydrazinomethyl Resins.
Table III.12 Hydrazino Group Capacities of Hydrazinomethyl Resins, 15a - 15e
Table III.13 Hydrazino Group Capacities of Hydrazinomethyl Resins 16a-16e
Table III.14 Hydrazino Group Capacities of Hydrazinomethyl Resins; 15a, 16a, 17 & 18
e. Preparation and Characterization of Mixed Benzoic Dithiocarbazic Anhydride Resins.
Table III.15 Analytical Details of Mixed Benzoic Dithiocarbazic Anhydride Resins.
f. Effect of the Nature of the Cross linking Agent on the Benzoyl Group Capacity of Mixed Benzoic Dithiocarbazic Anhydride Resins.
Table III.16 Comparison of the Observed Benzoyl Group Capacities of Mixed Benzoic Dithiocarbazic Anhydride Resins 23a, 24a, 25. and 26 with the Theoretical Capacities.
g. Effect of the Extent of Cross linking on the Benzoyl Group Capacity of Mixed Benzoic Dithiocarbazic Anhydride Resins.
h. Kinetics of the Benzoyl Group Transfer Reactions of Mixed Benzoic Dithiocarbazic Anhydride Resins.
(i) Effect of the Molecular Character of Cross linking on the Rate of Benzoyl Group Transfer.
Table III.17 Extents of Benzoyl Group Transfer by Polymer-Bound Mixed Benzoic Dithiocarbazic Anhydrides 23a, 24a. 25 and 26.
(ii) Effect of the Extent of Cross linking on the Rate of Benzoyl Group Transfer.
5. Effect of the Nature of Diluent and Monomer / Diluent Volume Ratio on the Reactivity of Polymer-Supported Mixed Benzoic Dithiocarbazic Anhydride.
a. Preparation of Diluent-Modified 10% HDODA Cross linked Polystyrene Resins.
Table III.18 Particle Size Distribution in Diluent-Modified 10%HDODA -Crosslinked Polystyrene Resins 8c -8c6
b. Functionalization of the Diluent-Modified Supports with the Mixed Benzoic Dithiocarbazic Anhydride Function and Comparison of the Rates of Benzoyl Group Transfer.
Table III.19 Details of Functionalization of Diluent-Modified 10% HDODA - Crosslinked Polystyrene Resins with Mixed Benzoic Dithiocarbazic Anhydride Function and Comparison of Reactivity.
c. Swelling Characteristics of the Diluent-Modified Polymers
Table III.20 Swelling Capacities of Diluent-Modified 10% HDODA -Crosslinked Polystyrene Resins
6. Effect of the Local Concentration of the Mixed Benzoic Dithiocarbazic Anhydride Function on the Rate of Benzoyl Group Transfer.
Table III.21 Effect of the Local Concentration of the Mixed Benzoic Dithiocarbazic Anhydride Function on Reactivity
7. Effect of Particle Size on Reactivity.
Table III.22 Effect of Particle Size on the Rate of Benzoyl Group Transfer in Polymer-Bound Mixed Benzoic Dithiocarbazic Anhydride.
8. Effect of Solvent on the Rate of Benzoyl Group Transfer.
Fig.III.4 Effect of the Solvent on the Rate of Benzoyl Group transfer in Polymer-Bound Mixed Benzoic Dithiocarabazic Anhydrides
9. Synthesis of Model Peptides.
a. The Acid Chloride Method.
b. The Anhydride Method.
Table III.23 Details of Peptides prepared using Polymer-Bound Mixed Aminoacyl Dithiocarbazic Anhydrides.
IV. POLYMER-BOUND MIXED CARBOXYLIC XANTHIC ANHYDRIDES AS SOLID-PHASE ACYL TRANSFER REAGENTS
Results and Discussion
1. Solid-Phase Acylation Reactions using Cross linked Polystyrene Bound Mixed Carboxylic Antic Anhydrides.
a. Preparation and Characterization of Cross linked Polystyrene-Bound Mixed Carboxylic Xanthic Anhydrides.
Table IV.1. Analytical Details of Polymer --Bound Mixed Carboxylic Xanthic Anhydrides.
b. Acylation of Amines using Polymer-Bound Mixed Carboxylic Xanthic Anhydrides.
Table IV. 2 Benzoylation using Polymer-Bound Mixed Benzoic Xanthic Anhydride
Table IV.3 p-Nitrobenzoylation using Polymer-Bound Mixed Benzoic Xanthic Anhydride
Table IV.4 Acetylation using Polymer-Bound Mixed Acetic Xanthic Anhydride (32C)
c. Recycling of the spent Reagent.
d. Effect of the Extent of Cross linking on the Reactivity of DVB-Crosslinked Polystyrene-Bound Mixed Benzoic Xanthic Anhydride.
Table IV.5 Details of the Conversion of Chloromethyl Resins -11a-11e to Hydroxmethyl Resins 34a-34e
Table IV. 6 Details of the Conversion of Hydroxymethyl Resins 34a - 34e to Xanthate Resins 35a - 35e
Table IV.7 Extent of Benzoylation of Benzylamine using Polystyrene-Bound Mixed Benzoic Xanthic Anhydrides (36a-36e)
2. Solid-Phase Acylation Reactions using Crosslinked Poly (2 hydroxyethyl methacrylate) -Supported Mixed p-Nitro benzoic Xanthic Anhydrides.
a. Preparation of Crosslinked Poly (2-hydroxyethyl methacrylate) Resins.
Table IV. 8 Details of the Preparation of Poly (2- hydroxyethyl methacrylate) Crosslinked with TEGDMA, TTEGDA, HDODA, and DVB (37-40)
Table IV. 9 Details of the Preparation of PHEMA Crosslinked with Varying mole% of NNMBA (4la-4le)
b. Solvation Characteristics of Crosslinked PHEMA Resins: Effect of Molecular Character and Extent of Cross linking on Swelling.
(i) Effect of the Molecular Character of Cross linking on Swelling.
Table IV.10 Swelling Capacities of PHEMA Crosslinked with 2% TEGDMA, TTEGDA, HDODA, DVB, & NlMMBA (37-40 7 41a)
(ii) Effect of the Extent of Cross linking on Swelling
Fig.IV.l. Effect of the Extent of Crosslinking on the Swelling of HEMA-NNMBA Copolymers.
c. Preparation and Characterization of Crosslinked Poly (2-hydroxyethyl methacrylate) -Bound Mixed p-Nitro benzoic Xanthic Anhydrides.
Table IV.11 Details of the Preparation of Mixed p-Nitrobenzoic Xanthic Anhydrides Supported on PHEMA-Crosslinked with 2%, TEGDMA, TTEGDA, HDODA, DVB & NNMBA
Table IV. 12 Details of the Preparation of NNMBA Crosslinked PHEMA - Bound Mixed Carboxylic Xanthic Anhydrides
(i) Effect of the Molecular Character of Cross linking on the Capacity of the Resins.
Table IV.13 Xanthate Group Capacities of Resins Derived from PHEMA Crosslinked with % TEGDMA, TTEGDA, HDODA, DVB, & NNMBA (42-45 and 46a)
(ii) Effect of the Extent of Cross linking on Capacity
Table IV.14. Xanthate Capacities of Resins Derived from HEMA-NMMBA Copolymers
d. Effect of the Molecular Character and Extent of Cross linking on the Reactivity of the Acyl Group.
Table IV.15. Extent of p-Nitrobenzoylation Using Mixed p-Nitrobenzoid Xanthic Anhydride Resins 47-50 and 51a
Table IV.16. Extent of p-Nitrobenzoylation Using Mixed p-Nitrobenzoic Xanthic Anhydride Resins 51a-51e
(i) Effect of the Molecular Character of Cross linking
(ii) Effect of the Extent of Cross linking.
Fig. IV.2. Effect of the Extent of Crosslinking on the Capacity and Reactivity of NNMBA
e. Influence of the Nature of the Polymer Backbone on Reactivity.
V. SOLID-PHASE ACYL TRANSFER REAGENTS DERIVED FROM POLYMER-BOUND THIOLS.
Results and Discussion
1. Solid-Phase Acylation Reactions Using Polymer-Supported Mixed Carboxylic Thioxanthic Anhydrides.
a. Preparation and Characterization.
b. Acylation Reactions using Polymer-Bound Mixed Carboxylic Thioxanthic Anhydrides.
Table V.2 Benzoylation using Polymer-Bound Mixed BenzoicThioxanthic Anhydride (55a)
Table V.3 p-Nitrobenzoylation using Polymer-Bound Mixed p-Nitrobenzoic Thioxanthic Anhydride 55b
Table V.4 Acetylation using Polymer-Bound Mixed Acetic Thioxanthic Anhydride 55c
c. Recycling of the Spent Reagent Resin.
Table V.5 Benzoyl Group Capacities of Polymer-Bound Mixed Benzoic Thioxanthic Anhydride after Repeated Recycling Processes.
d. Effect of the Extent of Cross linking on the Reactivity.
Table V.6 Capacity of Polymer-Bound Thiols Derived from DVB-Crosslinked Polystyrene Resins.
Table V.7 Capacities of Thioxanthate Resins Derived from DVB - Crosslinked Polystyrene Resins
Table V.8 Extent of Benzoylation by Polymer-Bound Mixed BenzoicThioxanthic Anhydride
2. Polymer-Bound Thiol Esters as Acyl Transfer Reagents.
a. Acylation Reactions using S-Benzoyl Mercaptomethyl Polystyrene.
Table V.9 Yield of the Benzoylation Products of Amines by S-Benzoyl Mercaptomethyl Polystyrene
Table V.10 Extent of Benzoylation of Benzylamine at Different Temperatures using S-Benzoyl Mercaptomethyl Polystyrene
b. Solid-Phase Acylation Reactions using Polymeric S-Benzoyl Thioglycolamide.
Table V.ll Acylation of Amines with PolymericS- Benzoyl Thioglycolamidee
VI. EXPERIMENTAL
Preparation of Crosslinked Polystyrene Resins (7a-7e, 8a-8c, 8c1-8c6, 2 & 10) by Suspension Polymerization: General Procedure
Chloromethyl Methyl Ether- 234 (a potent carcinogen)
Preparation of 1 M ZnCl2 Solution in THF
Chloromethylation of Crosslinked Polystyrene Resins
Estimation of Chlorine in Chloromethyl PolystyreneResins (Volhards Method)
Preparation of Hydrazinomethyl Resins: General Procedure
Estimation of Hydrazino Group Capacity: General Procedure
Preparation of Dithiocarbazate Resins: General Procedure
Mixed Benzoic Dithiocarbazic Anhydride Resins: General Procedure
Estimation of Sulphur in the Resins: General Procedure
Estimation of Acyl Group Capacity: General Procedure
Benzoylation of Amines with Polymeric Mixed Benzoic Dithiocarbazic Anhydride
Preparation of Mixed p-Nitrobenzoic Dithiocarbazic Anhydride Resin
p-Nitrobenzoylation of Amines using Resin
Preparation of Polymer-Bound Mixed Acetic Dithiocarbazic Anhydride
Acetylation of Amines Using Resin
Determination of the Extent of Benzoylation by Mixed Benzoic Dithiocarbazic Anhydride Resins
Preparation of Boc Azide
Preparation of Boc Glycine-Schnabels method
Preparation of Alanine Methyl Ester Hydrochloride: Thionyl Chloride -Methanol Procedure
Preparation of Glycine Benzyl Ester p-Toluene Sulphonate
Polymer-Bound Bz-Gly: Preparation of Resin
Synthesis of the Peptide Bz-Gly-Ala-QMe
Synthesis of the Peptide Bz-Gly-Gly-O-Bzl
Preparation of Boc-Gly_Resin
Synthesis of the Peptide Boc-Gly-Ala-OMe
Preparation of Hydroxymethyl Resins (30, 34a-34e): General Procedure
Estilation of Hydroxyl Capacity
Preparation of Xanthate Resins (31, 35a-35e): General Procedure
Estimation of Xanthate Capacity
Mixed Benzoic Xanthic Anhydride Resins (32a, 36a-36e): General Procedure
Polymer-Bound mixed p-Nitrobenzoic Xanthic Anhydride
Acylation of Amines using Mixed Carboxylic Xanthic Anhydride Resins 32a and 32b: General Procedure
Preparation of Mixed Acetic Xanthic Anhydride Resin
Acetylation of Amines with the Mixed Acetic Xanthic Anhydride Resin
Suspension Polymerization of HEMA: Preparation of Crosslinked PHEMA
Preparation of NNMBA-Crosslinked PHEMA: Resins
Conversion of Crosslinked PHEMA to Xanthate Resins (12-45 and 46a - 46e)
Preparation of Crosslinked PREMA - Bound Mixed p-Nitrobenzoic Xanthic Anhydrides (47-50 & -51a - 51e): General Procedure
Determination of the Course of p-Nitrobenzoylation of Piperidine using the Mixed p-Nitrobenzoic Xanthic Anhydride Resin: General Procedure
Determination of Swelling Capacities
Preparation of Mercaptomethyl Polystyrene
Estimation of Thiol Capacity
Preparation of Thioxanthate Resins: General Procedure
Estimation of Capacity of Thioxanthate Group
Preparation of Polymer-Bound mixed Benzoic Thioxanthic Anhydrides: General Procedure
Mixed p-Nitrobenzoic Thioxanthic Anhydride Resin
Acylation of Amines using the mixed Anhydride Resins: 55a&55b
Preparation of Mixed Acetic Thioxanthic Anhydride Resin
Acetylation of Amines with Resin
Preparation of S-Benzoyl Mercaptomethyl Polystyrene
Preparation of Aminomethyl Polystyrene
Preparation of Polymer-Bound Thioglycolamide
Preparation of S-Benzoyl Thioglycolamide Resin
Acylation of Amines using Polymer-Bound Thiol Esters (52 and 60)
VII. SUMMARY AND OUTLOOK
VIII. REFERENCES