SUPERIOR SWELLING PROPERTIES OF RESINS OF POLY-N-ACRYLYLDIALKYLAMINES OVER POLYSTYRENE IN SOLVENTS FOR PEPTIDE SYNTHESIS

Three beaded poly-N-acrylyldialkylamine resins have been systematically compared with polystyrene-co-1%-divinylbenzene for their ability to interact with solvents that are useful in peptide synthesis. The three resins have the same cross-linking monomer, N,N¹-bisacrylyl-1,2-diminoethane, and functionalizing monomer, N-acrylyl-1,6-diaminohexane hydrochloride. They differ from one another in the compositions of the base monomer, degree of cross-linking (DC), quantity of functionalizing monomer, or monomer dilution ratio (MDR, ratio of inert solvent to monomers by weight). Resin 1 is poly-N-acrylylpyrrolidine containing 0.75 mmol/g of amino function with DC 4.4 and MDR 4; resin 2 is poly-N-acrylyldimethylamine containing 0.75 mmol/g of amino function with DC 4.4 and MDR 4; resin 3 is poly-N-acrylyldimethylamine with DC 10 and MDR 6.8. Swelling was the property used as the measure of solvation in a given solvent for the macroscopically insoluble polymers. In their protonated or acylated forms resins 1—3 exhibit favorable swelling properties in methanol, ethanol, 2,2,2-trifluoroethanol, 2-propanol, acetic acid, and water, solvents in which polystyrene either swells little or not at all. In addition, the resins swell in methylene chloride, chloroform and dimethylformamide, solvents commonly used in the Merrifield method of solid-phase peptide synthesis, to about the same extent as polystyrene. The favorable swelling properties of the poly-N-acrylyldialkylamine resins should not only allow the use of most of the techniques developed for the solid-phase method, but should allow the invention and application of new techniques that rely on aqueous or other polar solvents.