3-Amino-4-(diphenylamino)-1<i>H</i>-2-benzopyran-1-one

Abstract

Various synthetic methodologies to obtain 3,4-diaminoisocumarin nucleus have been reported and described. However, mechanistic analysis based on experimental evidence is lacking. Herein, we report the synthesis of the novel 3-amino-4-(diphenylamino)-1H-2-benzopyran-1-one using a two-step methodology with a new mechanistic proposal to explain the formation of the latter based on previously reported precursors and the established conditions. This compound was afforded in 80% yield.

Keywords

• phthalides
• isobenzofuranones
• diaminoisocoumarins
• ring contracting rearrangement