Ethyl Acetoacetate → HCID 22642453, compound

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Reaction Steps

To 5.7 g of 3-(3-chlorophenylamino)-1-phenyl-2-pyrazolin-5-one were added 2.8 g of ethyl acetoacetate and 40 ml of acetic acid and the mixture was heated while refluxing for 6 hours. The precipitated crystals were filtered and washed with isopropyl alcohol to obtain 2 g of 7-(3-chlorophenyl)-4-methyl-2-phenylpyrazolo[3, 4-b]pyridine-3,6-dione (melting point: 278° to 282° C.). A solution was prepared by adding 24 ml of methanol and 1.12 ml of triethylamine to 1.4 g of the crystals obtained above, 1.13 g of 1,7-diphenyl-1,7-diaza-1,3,5-heptatriene hydrochloride were added to this solution, and then 0.75 ml of anhydrous acetic acid was added with stirring at room temperature for one hour. The precipitate thus formed was filtered and washed with methanol, followed by drying to obtain 5-[5-(N-acetylanilino)-2, 3-pentadienylidene]-7-(3-chlorophenyl)-4-methyl-2-phenylpyrazolo[3, 4-b]pyridine-3,6-dione. 30 ml of N,N-dimethylformamide and 0.32 g of 8-(3-chlorophenyl)-4-methyl-2-phenylpyrazolo[3, 4-b]pyridine-3,6-dione were added to 0.5 g of this product, and the solution was stirred at 50° C. for 2 hours. After filtering the reaction solution, ethyl acetate in an amount of ten times by volume was added while stirring to precipitate crystals. The obtained crystals were dissolved again in a small amount of N,N-dimethylformamide, and then ethyl acetate in an amount of ten times by volume was added to precipitate crystals, followed by filtering, washing with ethyl acetate and drying to obtain 0.4 g of Compound 4. Melting point: 300° C. or higher.

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