Preparation of Number of Chalcone Compounds From 6-formyl-5-methoxy-1,3-benzoxathiol

A number of chalcones were prepared by condensing of acetyl arene with 6-formyl-5-methoxy-1,3- benzoxathiol under acidic conditions. Base-catalyzed Claisen-Schmidt condensation could not be used to prepare of chalcones due to the oxathiol ring sensitivity in both the starting material and products to the alkali. The percentage of the yields depended on the substituent s in the products isolated. The electronwithdrawing groups increase the reaction rate and product percentage, while the electron-donating groups decrease the reaction rate and product percentage .Where the low yields were observed for o-substituted compounds (B4 and B10), while the high yields were obtained for m- and p-substituted compounds due to the steric hindrance in o-substituted compound. The products were characterized by FT-IR , UV/VIS spectroscopy and melting points.