With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.15456-86-7,4-Bromo-1,2-dihydropyridazine-3,6-dione,as a common compound, the synthetic route is as follows.
c) 3,4,6-Trichloropyridazine; This was prepared by a slight variation on the method of Kasnar et al, Nucleosides & Nucleotides (1994), 13(1-3), 459-79.Hydrazine sulphate salt (51 g) was suspended in water (250 ml), heated to reflux and bromomaleic anhydride (90.38 g) was added dropwise. The mixture was heated at reflux for 4 hours then cooled to room temperature. The reaction was repeated with 29 g hydrazine sulphate, 53 g bromomaleic anhydride and 130 ml water. The precipitates were collected by filtration, washed with water and acetone and dried as a combined batch in vacuo to afford 4-bromo-1,2-dihydro-3,6-pyridazinedione as a white solid (113 g). The solid in two batches was treated with phosphorus oxychloride (2¡Á200 ml) and heated to reflux for 3.5 hours. The mixture was cooled, evaporated and azeotroped with toluene. The residue was partitioned between dichloromethane and saturated aqueous sodium bicarbonate solution and extracted with DCM twice more. The organic extracts were dried and evaporated. This residue was re-dissolved in dichloromethane, and chromatographed on silica gel (300 g) (DCM as eluent) to give a white solid (101.5 g, 87%).(LC-MS analysis showed ca 20-30% impurity, isomers of bromo-dichloropyridazine).MS (+ve ion electrospray) m/z 184/185/186 (MH+), trichloropyridazine.MS (+ve ion electrospray) m/z 228/229/231 (MH+), bromo-dichloropyridazine.
15456-86-7, As the paragraph descriping shows that 15456-86-7 is playing an increasingly important role.
Reference£º
Patent; GLAXO GROUP LIMITED; US2010/56502; (2010); A1;,
Pyridazine – Wikipedia
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