With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.289-80-5,Pyridazine,as a common compound, the synthetic route is as follows.
50 mL of ammonia was condensed in a 200 mL, 3-NECK flask equipped with dry ice condenser. After the addition of a crystal of Fe (N03) 3, potassium (468 mg, 12.0 mmol) was added in small pieces AT-78 C. The cooling bath was removed and the intense dark blue mixture was brought to a gentle reflux until a light grey slurry was obtained. After cooling TO-78 C, 0.35 mL (4.80 mmol) of pyridazine was added and the mixture was stirred for 10 minutes. Solid KM : NO4 (2. 65 g, 16. 8 mmol) was added in small portions, the cooling bath was removed, and the mixture was stirred for 10 minutes The reaction was carefully quenched with 1.2 g of solid ammonium chloride. 20 mL of methanol was added and the ammonia was left to evaporate in the hood. The black mixture was filtered through CELIEZ filter aid, the filtrate was concentrated in vacuo, and the resulting black solid was purified on SI02 (100% CH2CL2 to 10% MeOH in CH2C12, gradient) to yield pyridazin-4-ylamine as a brownish solid (380 mg; 83% yield). Bromination of pyridazin-4-ylamine was performed in the same manner as for the preparation of 4-amino-3-bromo-2,6-dimethylpyridine. Chromatography on Si02 (20% ethyl acetate in hexanes to 100% ethyl acetate, gradient, followed by 2% methanol in ethyl acetate) yielded 4- amino-3-bromopyridazine (first eluting: 15% yield) and 4-amino-5-bromopyridazine (second eluting: 5% yield) as tan solids.
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Reference£º
Patent; BOEHRINGER INGELHEIM PHARMACEUTICALS, INC.; WO2005/30213; (2005); A1;,
Pyridazine – Wikipedia
Pyridazine | C4H4N2 – PubChem