* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
2-phenylnaphtho[2,3-d]oxazole-4,9-dione (A) Intermediate 3 (500 mg, 1.0 eq), trimethylorthobenzoate (3.6 mL, 8.0 eq) and PPTS (66 mg, 0.1 eq) were combined and heated at 90° C. (oil bath) for 2 hours at which point LC-MS analysis indicated complete consumption of starting material. The reaction mixture was diluted with Et2O and the resulting yellow ppt collected and washed with Et2O and EtOAc and dried to yield desired product (472 mg, 65percent) as a bright yellow fluffy solid. 1H NMR (400 MHz, CDCl3): δ 7.53-7.62 (3H, M), 7.81 (2H, dd, J=3.5, 5.9), 8.25 (1H, dd, J=3.3, 5.7), 8.29 (1H, dd, J=3.1, 5.9), 8.31-8.34 (2H, M). LRMS (M+H)+: 276.19.
With indium; acetic acid; In ethyl acetate; for 1.5h;Reflux; Inert atmosphere;
General procedure: 2-Nitroaniline derivative (1 mmol) was added to a mixture of indium powder (574 mg, 5.0 mmol for 2-nitroaniline, 918 mg 8.0 mmol for 1,2-dinitroarene), and acetic acid (0.572 mL, 10 mmol) in ethyl acetate (2 mL), followed by the addition of trimethyl orthoester (2.0 mmol) in ethyl acetate (3 mL for 2-nitroaniline; 8 mL for 1,2-dinitroarene). The reaction mixture was stirred at reflux under a nitrogen atmosphere. After the reaction was completed, the reaction mixture was diluted with ethyl acetate (30 mL), filtered through Celite, poured into 10% NaHCO3 (30 mL), and then extracted with ethyl acetate (30 mL×3). The combined organic extracts were dried over MgSO4, filtered, and concentrated. The residue was eluted with ethyl acetate/hexane (v/v=10/90) for 2-phenylbenzimidazole derivatives or methanol/dichloromethane (v/v=1/99) for 2-methylbenzimidazole derivatives through a silica gel column to give the corresponding benzimidazoles. The structures of the benzimidazoles were characterized by 1H NMR, 13C NMR, FTIR, and GC-MS, and were mostly known compounds. HRMS data were reported in addition for unknown compounds.
Chemistry
Pharmaceutical Intermediates
Inhibitors/Agonists
Material Science
For Research Only
120K+ Compounds
Competitive Price
1-2 Day Shipping
