Diisopropylethylamine → 2-(trimethylsilyl)ethyl 3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

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Reaction Steps

To a solution of 3-(pyrazin-2-yl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine (1.0 g, 5.0 mmol) and N,N-diisopropylethylamine (1.7 mL, 9.9 mmol) in DMF (15 mL) was added 1-[2-(trimethylsilyl)ethoxycarbonyloxy]pyrrolidin-2,5-dione (1.5 g, 5.9 mmol). Stirred for 18 h and poured into ice cold brine (150 mL). Precipitate filtered and washed successively with water and ether to afford the desired product as a white solid (1.5 g, 89%). MS (ESI): mass calcd. for C15H22N6O2Si, 346.2; m/z found, 347.2 [M+H]+. 1H NMR (500 MHz, CDCl3) δ 9.50 (d, J=1.4 Hz, 1H), 8.56 (d, J=2.5 Hz, 1H), 8.52-8.48 (m, 1H), 4.91 (s, 2H), 4.60-4.45 (m, 2H), 4.25-4.14 (m, 2H), 3.87 (t, J=5.3 Hz, 2H), 1.07-0.92 (m, 2H), 0.01-0.04 (m, 9H).

Provenance & Evidence