A new method for the solid phase synthesis of benzothiazoles and 2-arylamino-3-carboxyl-4- hydroxy-5-arylthiophenes is described. Resin bound cyclic malonic acid ester was reacted with aryl isothiocyanates and then with bromine or α-bromoketones, followed by treatment with perchloric acid or sodium methoxide to afford substituted 2-methylbenzothiazoles or 2- arylamino-3-carboxyl-4-hydroxy-5-arylthiophenes, respectively, in high yields and purities.
