Synthesis of Thiourea Derivatives on Soluble Polymeric Support

A modified poly(ethylene glycol) (PEG) has been developed as the soluble polymeric supports for liquid phase synthesis of novel thiourea derivatives. In each step of the sequence, the PEG bound products were precipitated in cold Et 2O and the unreacted materials and by products were removed by simple filtration. The progress of reaction, purity of the isolation and the structure of the PEG bound products were easily monitored by TLC, IR and 1H NMR spectra. Representative thiourea derivatives were obtained in moderate yields with excellent purity from this modified PEG bound product by the cleavage with 50% TFA/H 2O.