Downstream synthetic route of 76240-49-8

As the paragraph descriping shows that 76240-49-8 is playing an increasingly important role.

76240-49-8, 6-Bromophthalazine-1,4-diol is a phthalazine compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

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.

As the paragraph descriping shows that 76240-49-8 is playing an increasingly important role.

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;,
Phthalazine – Wikipedia
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