Water → 3-(4-tert-Butoxycarbonyl-1-piperazinyl)-2(1H)-pyrazinone

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Reaction Steps

2-Chloro-3-(4-tert-butoxycarbonyl-1-piperazinyl)pyrazine* (60 g, 0.20 mol) was added to a mixture of NaOH (100 g, 2.50 mol), water (100 mL) and DMSO (100 g) at 100° C. After being stirred for 3 h, the mixture was allowed to cool and partitioned between toluene (100 g) and water (200 mL). Water (300 mL), crushed ice (200 g), EtOAc (600 g) and sodium chloride (100 g) were added to the aqueous layer. The layers were separated and the aqueous layer was extracted with an additional portion of EtOAc (600 g). The combined organic layers were concentrated in vacuo to furnish 38 g (68%) of the title product. 1H and 13C NMR data support the stated structure. HPLC purity: 100%. HRMS m/z calcd for C13H20N4O3 (M)+ 280.1535, found 280.1530. *Prepared according to the procedure described in WO 00/76984, Example 52, Step 1.

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