Synthesis of Bis(2,4‐diarylimidazol‐5‐yl) Diselenides from N‐Benzylbenzimidoyl Isoselenocyanates

The reaction of N‐benzylbenzamides 6 with SOCl₂ under reflux gave the corresponding N‐benzylbenzimidoyl chlorides 7 . Further treatment with KSeCN in dry acetone yielded imidoyl isoselenocyanates 3 (Scheme 2). These compounds, obtained in satisfying yields, proved to be stable enough to be purified and analyzed. Reaction of 3 with morpholine in dry acetone led to the corresponding selenourea derivatives 8 . On treatment with Et₃N, the 4‐nitrobenzyl derivatives of type 3 were transformed into bis(2,4‐diarylimidazol‐5‐yl) diselenides 9 (Scheme 3). This transformation takes place only when the benzyl residue bears an NO₂ group and the phenyl group is not substituted with a strong electron‐donating group. A reaction mechanism for the formation of 9 is proposed in Scheme 4. The key structures have been established by X‐ray crystallography.