Preparation of NaNbO.sub.3 nanoplates and their application in the synthesis of arylidene indan-1,3-diones, functionalized C-3 isobenzofuranones and Meldrum's acid derivatives

The present investigation describes the preparation of a sodium niobate nanostructured material and the application of it as catalyst in condensation reactions. Well-defined NaNbO.sub.3 nanoplates were obtained via a basic hydrothermal process using Nb.sub.2O.sub.5·nH.sub.2O as starting material. The NaNbO.sub.3 nanostructured catalyst was characterized by scanning electron microscopy (SEM) and X-ray diffractometry (XRD), N.sub.2 adsorption/desorption isotherms, and hydrogen temperature-programmed reduction (H.sub.2-TPR) analysis. The performance of NaNbO.sub.3 as a catalyst was evaluated in condensation reactions for the preparation of 2-arylidene indan-1,3-diones, C-3 functionalized isobenzofuran-1(3H)-ones, Meldrum's acid derivatives, and a coumarin. The products obtained in these reactions present several important bioactivities and are useful building blocks in organic synthesis. The condensation reactions were run under microwave irradiation and without the use of solvents. The compounds prepared in the condensation reactions were purified by recrystallization and obtained with satisfactory yields and short reaction times. The catalyst can be recycled in the condensation processes.