Metal free synthesis of functionalized 1-aryl isoquinolines via iodine mediated oxidative dehydrogenation and ring opening of lactam in isoindoloisoquinolinones

A facile and convenient method for the synthesis of substituted 2-(isoquinolin-1-yl)benzoic acids from isoindoloisoquinolinones in the presence of molecular iodine under sealed tube condition at 100 has been developed. This methodology involves the oxidative dehydrogenation and ring opening of hydroxy lactam/methoxy lactam to furnish the 2-(isoquinolin-1-yl)benzoic acids. Some of these acids are successfully cyclized to furnish the azabenzanthrone derivatives, the potential precursors for the synthesis of menisporphine alkaloids and daurioxoisoaporphines.