Microwave Assisted Preparation of Flavylium Salts with Perchloric Acid Impregnated on Silica Gel Under Solvent-free Conditions

Perchloric acid immobilized on silica gel (SiO2–HClO4) has been utilized as a mild and cheap reagent for onepot preparation of different varieties of flavylium salts via tandem reaction of different acetophenones with Salicylaldehydes under solvent-free conditions. Different reaction conditions such as conventional heating and microwave irradiation have been investigated. The corresponding flavylium salts have been prepared in high yields. The procedure is milder and more convenient than the known procedures.