Catalyst Free Synthesis of Pyridine-2,6-bis(2-bromo-propane-1,3-dione) and Pyrdine-2,6-bis(iN/i-arylthiazoline-2-thiones)

摘要

We have described herein a catalyst-free preparation method of pyridine-2,6-bis(N-alkylthiazoline-2-thiones) (4a-i) by the reaction of primary amines, CS2, and pyridine-2,6-bis(2-bromo-1,3- dicarbonyl) derivatives (2a-c) in water. Also, we have described a catalyst free, green chemistry protocols to monobromination of pyridine-2,6-bis(2-bromo-1,3-dicarbonyl) derivatives with high yield, using NBS as a brominating agent, that led to eco-friendly isolation and purification proce-dures. Furthermore, we have studied the reactivity of pyridine-2,6-bis(2-bromo-1-methyl-pro- pane-1,3-dione) (2a) towards thiourea to afford 2,6-bis(5-benzoyl-2-aminothiazol-4-yl)pyridine (9).