Which of the following compounds is the most basic?

Step-by-step solution

The basicity of a compound depends on the availability of the lone pair of electrons on the nitrogen atom for protonation. In compounds (1) and (2), the nitrogen atom is part of a fused bicyclic system. The rings are flexible enough to allow the nitrogen to adopt an sp^2 -like planar geometry. Consequently, the lone pair on nitrogen undergoes delocalization into the -system of the adjacent carbonyl group(s) via resonance. This strong amide/imide resonance decreases the electron density on nitrogen, making compounds