Formylation versus Alkylation of Secondary Amines in DMF

2,2'-(Formamidedi-2,1-ethanediyl)bis-1H-isoindole-1,3(2H)-dione (1), C₂₁H₁₇N₃O₅, is a product of a slow formylation reaction between refluxing DMF and 2,2'-(iminodi-2,1-ethanediyl)bis-1H-isoindole-1,3(2H)-dione (DPDA) which appears to be more efficient than the competing base-promoted alkylation with tris(chloroethyl)amine. The molecules adopt a folded conformation and pack efficiently to form sheets (in the a and c directions) having a `W in W' and `M in M' motif running along the c direction.

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