Copper oxide nanoparticle mediated ‘click chemistry’ for the synthesis of mono-, bis- and tris-triazole derivatives from 10,10-dipropargyl-9-anthrone as a key building block

The synthesis of mono-, bis- and tris-triazole derivatives was accomplished using 10,10-dipropargyl-9-anthrone as a key starting material. Various acetylenic compounds (2-5) derived from 10,10-dipropargyl-9-anthrone on reaction with alkyl/benzyl bromides and sodium azide in the presence of 10 mol% of copper oxide nanoparticles along with 20 mol% sodium ascorbate in water afforded a wide variety of triazoles derivatives (8-13) under heating at 70 degree C. The salient features of the present protocol are: mild reaction conditions, a shorter reaction time, the reusability of the catalyst, and its applicability with a wide range of substrates. Moreover, the mono-triazole 8b undergoes extended assembly in the solid state forming a zig-zag supramolecular structure stabilized by pi - pi and C-H... pi interactions. Interestingly, the single crystal X-ray structure of 9b shows that it forms a supramolecular ball structure stabilized by a combination of C-H...O interaction and hydrogen bonding. Furthermore the presence of water molecules embedded in the crystal lattice of 9b allows these supramolecular balls to arrange in a chain generating a fascinating supramolecular architecture.