Acetic Acid → 6-(2,4-Dichlorophenyl)-2-[(4-methylpiperazin-1-yl)methyl]pyrazolo[1,5-a]pyrazin-4(5H)-one

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Reaction Steps

145 mg (0.32 mmol) of 6-(2,4-dichlorophenyl)-4-oxo-4,5-dihydropyrazolo[1,5-a]pyrazine-2-carb-aldehyde (Example 18A) were dissolved in 6 ml of methanol, and 64 mg (0.64 mmol) of 1-methylpiperazine, 4 Å molecular sieve and 58 mg (0.96 mmol) of acetic acid were added. Finally, 40.2 mg (0.64 mmol) of sodium cyanoborohydride were added and the mixture was stirred at RT for 15 h. The crude mixture was acidified with 2N hydrochloric acid and the resulting precipitate was filtered off with suction. This gave 120 mg (96% of theory) of the product as a solid which was reacted further without any further purification.

Provenance & Evidence