With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.1352925-63-3,Ethyl 4,6-dihydroxypyridazine-3-carboxylate,as a common compound, the synthetic route is as follows.
A solution of ethyl 4, 6-dihydroxypyridazine-3-carboxylate (compound 47.4; 3.2 g, 17.387 mmol) in phosphorus oxychloride (35 mL, 226.037 mmol) was heated at 100 C for 3.5 h. The resulting reaction mixture was cooled to ambient temperature and the excess of phosphorus oxychloride was removed under vacuum. The traces phosphorus oxychloride was further removed by azeotropic distillation with chloroform (50 mL). The resulting residue was taken up in to ice water and extracted with EtOAc (3 x 500 mL). The combined organic layers were washed with water (100 mL), brine (100 mL), dried over Na2S04, filtered and concentrated under reduced pressure. The resulting crude material was purified by flash chromatography (60-70% EtOAc in hexane) yielding ethyl 4, 6-dichloropyridazine-3- carboxylate (compound 47.3; 2.5 g, 11.310 mmol). LCMS: Method B, 3.750 min, MS: ES+ 219.98 (M+l)., 1352925-63-3
As the paragraph descriping shows that 1352925-63-3 is playing an increasingly important role.
Reference：
Patent; ORFAN BIOTECH INC.; MAAG, Hans; FERNANDES, Miguel Xavier; (160 pag.)WO2019/133813; (2019); A1;,
Pyridazine – Wikipedia
Pyridazine | C4H4N2 – PubChem