59608-52-5

Upstream product

• 591-50-4 iodobenzene 
• 24786-40-1 2-(2-propynylsulfanyl)-1H-1,3-benzimidazole 
• 134469-07-1 Benzimidazol-2-thiol 
• 1794-48-5 1-bromo-3-phenylprop-2-yne 

Downstream Products

• 59608-55-8 4-phenyl-2H-benzo[4,5]imidazo[2,1-b][1,3]thiazine 
• 59608-57-0 3-benzylbenzo[4,5]imidazo[2,1-b]thiazole 

Relevant academic research and scientific papers

Pd-Cu catalyzed heterocyclization during Sonogashira coupling: Synthesis of 3-benzylthiazolo[3,2-a]benzimidazole

The reaction of 2-mercaptopropargyl benzimidazole with various iodobenzenes catalyzed by Pd-Cu leads to the formation of 3-benzylthiazolo[3,2-a] benzimidazoles.

Cyclization of Thiopropargyl Benzimidazoles by Combining Iron(III) Chloride and Diorganyl Diselenides

A practical synthetic approach to the synthesis of 3-(organoselenyl)-imidazothiazines was developed. The methodology involved the regioselective 6-endo-dig cyclization of thiopropargyl benzimidazoles promoted by diorganyl diselenides and iron(III) chloride. The investigation to determine the best reaction conditions indicated the use of thiopropargyl benzimidazoles (0.25 mmol) with diorganyl diselenides (1.0 equiv) and iron(III) chloride (2.0 equiv) in dichloromethane at 40 °C for 30 min to be optimal. Under these conditions, the scope of the substrates was evaluated varying the structures of thiopropargyl benzimidazoles and diorganyl diselenides giving 28 3-(organoselenyl)-imidazothiazines in moderate to good yields. The reaction conditions were also applicable to diorganyl ditellurides; however, they did not work for diorganyl disulfides. The mechanism studies were carried out indicating that the cyclization proceeds via a cooperative action of diorganyl diselenides and iron(III) chloride, but a direct electrophilic cyclization, promoted by the in situ formed electrophilic organoselenium species, cannot be ruled out.