Oxazoline synthesis from hydroxyamides by resin capture and ring-forming release

Polymer-bound tosyl chloride was used to capture hydroxyamides (prepared from amino alcohols and acid chlorides) from the reaction mixtures in which they were formed. The resulting support-bound amide/ sulfonates undergo ring-forming cleavage from the polymer on treatment with weak base, forming oxazolines and oxazines in generally good yield and high purity. Low temperature is required in the polymer-loading step to slow the cleavage process and achieve high efficiency in the execution of the method.