Regioselective synthesis of indazolo[2,3-]quinazolines enabled by I/S-facilitated annulation relay dehydrogenative aromatization of cyclohexanones

A method for concise and efficient synthesis of indazolo[2,3- a ]quinazolines has been developed via a sequential annulation of 3-aminoindazoles and dehydrogenative aromatization of cyclohexanones. This high regioselectivity is attributed to the fact that the Mannich reaction is superior to the aldol reaction in this system. It is worth mentioning that this convenient process is successfully extended to 3-aminopyrazoles for assembling another class of medicinally prevalent pyrazolo[1,5- a ]quinazolines. A method for concise and regioselective synthesis of indazolo[2,3- a ]quinazolines has been developed via a sequential annulation and dehydrogenative aromatization of cyclohexanones.