Influence of resin cross-linking on solid-phase chemistry.
A range of PS-DVB resins were prepared by suspension polymerization with styrene, p-chloromethyl styrene, and DVB. Yields of polymerization increased (from 40% to almost 80%) with increasing cross-linking. The beads exhibited the expected swelling characteristics, with the 0.3% resin swelling to almost 9 times its dry volume in CHCl3. Kinetics of cleavage of the dye Methyl Red from the range of Rink linked resins showed rate enhancements of up to 500% between the 6.0 and the 0.3% cross-linked resins. Total synthesis of Kawaguchipeptin B was carried out on the resins, and their performance during the syntheses was investigated. Contrary to expectations, the purities of the cyclic peptide product increased with increasing resin cross-linking doubling from the 0.3-6.0% resin. A Suzuki reaction showed the half-lives of reaction increased with increasing resin cross-linking with an 11-fold increase in half-life between the 0.3-2.7% resin. Surprisingly, we observed very little reaction in the case of the 3.0 and 6.0% cross-linked resins.
Rana
S
S
Department of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, U.K.
White
P
P
Bradley
M
M
D000900:Anti-Bacterial Agents / Q000138:chemical synthesis*; D001391:Azo Compounds; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents; D003432:Cross-Linking Reagents / Q000737:chemistry*; D010455:Peptides; D010456:Peptides, Cyclic; D011137:Polystyrenes / Q000138:chemical synthesis / Q000737:chemistry*
D000900:Anti-Bacterial Agents; D001391:Azo Compounds; D004396:Coloring Agents; D003432:Cross-Linking Reagents; C095039:Merrifield resin; D010455:Peptides; D010456:Peptides, Cyclic; D011137:Polystyrenes; C107719:kawaguchipeptin B; C008492:methyl red; C003771:Amberlite XAD-2 resin