Poly(ethylene glycol) SupportedLiquid-Phase Synthesis of 1,2,4-Oxadiazolines

The liquid-phase synthesis of oxadiazolines via 1,3-dipolar cycloaddition reaction on poly(ethylene glycol) support (PEG) is described. 1,3-Dipolar cycloadditions of nitrile oxide generated in situ on soluble polymer with a variety of imines provided a library of 1,2,4-oxadiazolines in good yields and purity. The reactions were run in the homogeneous phase and the synthetic sequen­ces were performed in parallel one-pot fashion. Quantitative conversion in the 1,3-dipolar cycloaddition reaction was verified by 1H NMR analysis. The polymer bound products were isolated in excellent yields by simple precipitation of the soluble support.