Electric Literature of 1074-98-2 ,Some common heterocyclic compound, 1074-98-2, molecular formula is C6H6N2O3, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc., below Introduce a new synthetic route.
3-Methyl-4-nitro-pyridine-N-oxide (5.34 g, 34.7 mmol, 1 equiv.) and N,N-dimethylformamide diethyl acetal (10.5 mL, 61.4 mmol, 1.8 equiv.) were combined in 50 mL anhydrous DMF and heated to 120 C. for 3 h. The reaction was allowed to cool back to room temperature and the DMF solvent was removed in vacuo. The residue was treated with ~80 mL toluene, which was then removed in vacuo as well. Finally the residue was mixed with benzene and filtered. The desired vinyl amine was obtained as a dark purple solid (6.74 g, 32.2 mmol, 93%), which was used as is in the next step. The vinyl amine from above (3.37 g, 16.1 mmol, 1 equiv.) and 1.75 mL of water were mixed in 50 mL EtOH. Ammonium formate (4.56 g, 72.5 mmol) and 10% palladium-on-carbon (600 mg) were added and the mixture was heated to a gentle reflux for 1 h. TLC and MS (ES+) revealed no starting material but showed the presence of two major components, the desired 5-aza-indole and its N-oxide. The reaction was left stirring for a further 2 h after more ammonium formate and more palladium catalyst were added. Finally the reaction was cooled to room temperature, filtered and solvents removed in vacuo. 5% NaOH aqueous solution was added and the mixture was extracted with EtOAc. The combined organics were dried (MgSO4), filtered, and the solvent was removed in vacuo, providing 0.555 g of desired 5-aza-indole (4.70 mmol, 29% yield).
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route,1074-98-2, its application will become more common.
Reference:
Patent; Boehringer Ingelheim Pharmaceuticals, Inc.; US2003/162968; (2003); A1;,
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