Pyrazol-3-ylamine → HCID 178507945, 화합물

참여 물질

반응 단계

Sodium bicarbonate (3.9 g, 46.2 mmol) is added in small portions to a mixture of ethyl 3-ethoxy-3-iminopropanoate hydrochloride (Z-1) (8.6 g, 44.0 mmol) in crushed ice (100 g) and ethyl acetate (50 mL) until the pH value reaches 8-9. The organic layer is separated and the aqueous layer was extracted with ethyl acetate (2×50 mL). The combined organic layers are dried over anhydrous MgSO4 and filtered. The filtrate is concentrated in vacuo to afford a colourless oil which is added to a solution of 1H-pyrazol-5-amine (3.65 g, 44.0 mmol) in ethanol (100 mL). The resulting mixture is then degassed and backfilled with argon (three cycles) and stirred at reflux overnight. The mixture is then filtered while it was still warm. The solid is rinsed with cold ethanol (25 mL) and ether (2×25 mL), and then dried in vacuo to afford 5-aminopyrazolo[1,5-a]pyrimidin-7(4H)-one (Z-2).

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