Polytungstozincate Acid: A New and Efficient Catalyst for the Synthesis of Xanthenes Under Solvent-Free Conditions

Polytungstozincate acid was prepared from sodium polytungstozincate and after formulation, Na3H9(WZn3(H2O)2(ZnW9O34)2), was used as an efficient catalyst for the synthesis of xanthene derivatives under solvent- free conditions. The simple experimental procedure, short reaction times (40-120 min.), and excellent yields (81-94%) are the advantages of the present method.