Novel functional initiators for oxazoline polymerization

The initiating behavior of the functional tosylates 1-4 and triflates 5 and 6 for the cationic ring-opening polymerization of 2-methyl-1,3-oxazoline w as investigated. The emphasis was directed at tosylates and triflates with 2,2-dimethyl-1,3-dioxolane-, 2,3-epoxypropyl-, 2,3-didodecanoyl-glycerol-, and cholest-5-en-moieties that allow the construction of amphiphilic polyox azoline conjugates. The tosylates were prepared by a simple reaction of the corresponding alcohols with p-toluenesulfonyl chloride, whereas the prepar ation of the corresponding triflates required low temperature and the use o f 2,6-di-tert-butylpyridine as a sterically hindered base. Among the initia tors tested, 2,2-dimethyl-(4-trifluoromethanesulfonyloxymethyl)-1,3-dioxola ne 6 gave the best results in respect to molecular weight and polydispersit y. Starting from the corresponding functional oxazoline polymers obtained w ith 6 as an initiator, amphiphilic lipid-polyoxazoline conjugates with a di acylglycerol backbone could be prepared. (C) 2001 John Wiley & Sons, Inc.