With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.76240-49-8,6-Bromophthalazine-1,4-diol,as a common compound, the synthetic route is as follows.
6-Bromo-2,3-dihydrophthalazine-1 ,4-dione (25. g, 0.10 mol) was added to a mixture of phosphorus oxychloride (100. mL, 1 .06 mol) and thionyl chloride (100. mL, 1 .37 mol) under nitrogen, cooled to 0 C. Once the initial exotherm had subsided the reaction mixture was allowed to warm to ambient temperature and then heated at 100 C for 4 h. The mixture was then cooled to ambient temperature and then concentrated in vacuo. The residue was dissolved in iPrOAc (350 mL) and washed with saturated sodium bicarbonate solution (added until effervescence stopped), a precipitate formed, the two layers were filtered to isolate the first crop of the intermediate. The organic layer was collected and distilled to dryness to give the second crop of the intermediate. The solids were combined and partitioned between 1 ,4-dioxane (200 mL) and 2 N NaOH (100 mL). The resulting mixture was heated at 40 C overnight and then cooled to ambient temperature and left to stand. The solid precipitate was filtered (first crop of product) and the resulting solution partitioned between EtOAc (250 mL) and water (200 mL). Further precipitate formed which was filtered and combined with the first crop of the product, the organic phase was separated and evaporated to dryness to give the second crop of the product. Product isolated is a mixture of two regioisomers, 7-bromo-4-chloro-2H-phthalazin-1 -one and 6- bromo-4-chloro-2H-phthalazin-1 -one, total yield isolated (17.6 g, 68.0 mmol, 66%).1 H NMR (300MHz, DMSO-d6) delta = 13.02 (s, 1 H), 12.98 (s, 1 H), 8.36 (d, J = 2.1 Hz, 1 H), 8.22 (dd, J = 2.1 , 8.6 Hz, 1 H), 8.17 – 8.1 1 (m, 3H), 7.93 (d, J = 8.7 Hz, 1 H). 1 :1 mixture of the two regioisomers.A stirred solution of 7-bromo-4-chloro-2H-phthalazin-1 -one and 6-bromo-4- chloro-2H-phthalazin-1 -one (8.82 g, 33.99 mmol) (-1 :1 mixture of isomers), tris(dibenzylideneacetone)dipalladium(0) (1 .56 g, 1 .7 mmol) and Xantphos (1 .97 g, 3.4 mmol) in 1 ,4-dioxane (200 mL) was degassed with nitrogen. N,N-Diisopropylethylamine (12.1 mL, 68.0 mmol) and benzyl mercaptan (7.98 mL, 68.0 mmol) were then added sequentially to the flask, and the resulting mixture was heated at 60 C for 18 h.The two flasks were combined and distilled to dryness, the residue was suspended in DCM (200 mL). The mixture was agitated for 30 min and filtered to give the desired product as a -1 :1 mixture of regioisomers 7-benzylsulfanyl-4-chloro-2H-phthalazin- 1 -one and 6-benzylsulfanyl-4-chloro-2H-phthalazin-1 -one. The mixture of isomers was recrystallised with acetic acid (200 mL), with a hot filtration to remove inorganic impurities. The resulting crystalline solid was filtered, washed with AcOH and minimal amount of ether, yielding a white solid which was dried in the vacuum oven at 40 C, 7-benzylsulfanyl-4- chloro-2H-phthalazin-1 -one (5.35 g, 17.7 mmol, 26%). 1H NMR (300MHz, DMSO-d6) delta = 12.86 (s, 1 H), 8.07 (d, J = 2.1 Hz, 1 H), 7.95 (dd, J = 2.1 , 8.6 Hz, 1 H), 7.87 (d, J = 8.6 Hz, 1 H), 7.49 – 7.44 (m, 2H), 7.37 – 7.24 (m, 3H), 4.49 (s, 2H)
The synthetic route of 76240-49-8 has been constantly updated, and we look forward to future research findings.
Reference£º
Patent; CANCER RESEARCH TECHNOLOGY LIMITED; MCGONAGLE, Alison E.; JORDAN, Allan; WASZKOWYCZ, Bohdan; HUTTON, Colin; WADDELL, Ian; HITCHIN, James R.; SMITH, Kate Mary; HAMILTON, Niall M.; (497 pag.)WO2016/92326; (2016); A1;,
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