Rearrangement of 3-(4,5-dimethoxy-2-vinylphenyl)-2-methyl-5-nitroisoquinolin-1(2H)-one to 2-(6,7-dimethoxy-1-oxoisoquinolin-2(1H)-yl)-N-methylbenzamide: a mechanistic proposal

Nitro compounds are compounds of great versatility in organic synthesis due to their easy availability and transformation into a wide variety of functionalities.[1] As a part of our continued interest in nitro compounds, we few years ago reported the transformation of 3-(4,5-dimethoxy-2-vinylphenyl)-2-methyl-5-nitroisoquinolin-1(2H)-one (1) into 2-(6,7-dimethoxy-1-oxoisoquinolin-2(1H)-yl)-N-methylbenzamide (4), via 3-(4,5-dimethoxy-2-vinyl- phenyl)-2-methyl-5-nitroisoquinolin-1(2H)-one (2) and 3-(2-(2,2-dimethoxyethyl)-4,5-dimethoxy-phenyl)-2-methyl-5-nitroisoquinolin-1(2H)-one (3).[2] A mechanistic proposal for the novel, striking rearrangement of compound 3 to compound 4 will be discussed.