Ultrasound-assisted synthesis of 1,8-dioxo-octahydroxanthene derivatives catalyzed by p-dodecylbenzenesulfonic acid in aqueous media.

An efficient and convenient approach to the synthesis of 3,3,6,6-tetramethyl-9-aryl-1,8-dioxo-octahydroxanthene derivatives using p-dodecylbenzenesulfonic acid (DBSA) as the catalyst (10 mol.%) under ultrasound irradiation is described. This method provides several advantages such as environment friendliness, high yields and simple work-up procedure. In addition, water was chosen as a green solvent.

Ultrasound-assisted synthesis of 2-amino-2-chromenes with cetyltrimethylammonium bromide in aqueous media.

A general and practical synthetic route to 2-amino-2-chromenes in water in the presence of cetyltrimethylammonium bromide (CTABr) as catalyst is described under ultrasound irradiation.