1-Methylimidazolium triflouroacetate ([Hmim]TFA): An efficient reusable acidic ionic liquid for the synthesis of 1,8-dioxo-octahydroxanthenes and 1,8-dioxo-decahydroacridines

Brönsted acidic ionic liquid, 1-methylimidazolium triflouroacetate ([Hmim]TFA) catalyzed synthesis of 1,8-dioxo-octahydroxanthenes and 1,8-dioxo-decahydroacridines in excellent yields and short period of times at 80 °C. Anions effects of the ionic liquid on the reaction rate have been investigated. The ionic liquid was easily separated from the reaction mixture by water extraction and was recycled four times without any loss in activity.