Isoindoline
Isoindoline is a heterocyclic organic compound with the molecular formula CHN. The parent compound has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing ring. The compound's structure is similar to indoline except that the nitrogen atom is in the 2 position instead of the 1 position of the five-membered ring. Isoindoline itself is not commonly encountered, but several derivatives are found in nature and some synthetic derivatives are commercially valuable drugs, e.g. pazinaclone. Substituted isoindolines. 1-Substituted isoindolines and isoindolinones are chiral. Isoindolylcarboxylic acid and 1,3-disubstituted isoindolines  are constituents of some pharmaceuticals and natural products. Isoindolines can be prepared by 1,2-addition of a nucleophile onto a bifunctional ε-benzoiminoenoates followed by intramolecular aza-Michael reaction. Another route involves [3+2] cycloaddition of the azomethine ylides (e.g. (CH)NR) to quinone in the presence of suitable catalysts. These methods have also been adapted to give chiral derivatives.