A Nitro Group Distorting 2-Quinolone Skeleton

Abstract

Abstract - 1-Methyl-3,6,8-trinitro-2-quinolone shows high reactivity compared with 1-methyl-3.6-dinitro-2-quinolone. It was found the &nitro group activates a 2quinolone ring sterically rather than electronically. There are more than two hundred reports dealing a wide range of quinoline alkaloids from the Rutaceae family.' The majority of them has a 1-methyl-2-quinolone skeleton.2 From the viewpoint of biochemical activity, it is important to introduce various functional groups into a quinolone ring. In the mainly used methods for functionalization, the pre-introduced substituent such as OH, OR, =O and NRz groups is built into the skeleton^.^ In our previous paper$ we indicated the cine-substitution of 1-methyl-3,6,8-trinitro-2-quinolone (TNQ- Me) effectively caused regioselective C-C bond formation and enabled functionalization at the 4position directly. The starting quinolone has three ~tro groups, hut it has not been sure whether two of them on the benzene ring are necessary or not forthis reaction. In the present work, we studied the effect of the nitro group far from the reaction site on the reactivity of the 4-position using 1-methyl-3,6-dinitro-2-quinolone (DNQ-Me). We show that the 8-N@ group affects on a 2-quinolone ring sterically rather than electronically. The cine-substitution with 2,4pentanedione