Potassium Carbonate → Tert-butyl 4-(3-chloropyrazin-2-yl)piperazine-1-carboxylate

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Reaction Conditions

Reaction Steps

Charge a 2 L 3-neck round bottom flask with 2,3-dichloropyrazine (78.7 g, 0.532 mol), piperazine-1-carboxylic acid t-butyl ester (100 g, 0.537 mol), potassium carbonate (88.2 g, 0.638 mol) followed by N,N-dimethylacetamide (0.780 L), and heat the resultant slurry to 110° C. under nitrogen with vigorous stirring. Cool to room temperature, add water (0.390 L) and methyl t-butyl ether (0.390 L), and stir the mixture for 60 min. Stop stirring and separate the layers. Wash the organic layer with water (2×200 mL), dry over MgSO4, filter and concentrate to give 145 g of 3′-chloro-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4-carboxylic acid t-butyl ester as a yellow syrup (91% yield). 1H NMR (CDCl3) δ (ppm) 8.10 (s, 1H), 7.91 (s, 1H), 3.59 (m, 4H), 3.40 (m, 4H), 1.48 (s, 9H).

Provenance & Evidence