Potassium Hydroxide → {6-Methyl-2-oxo-3-[(2-phenylethyl)amino]pyrazin-1(2H)-yl}acetic acid

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Reaction Steps

(5-Chloro-6-methyl-2-oxo-3-phenethylamino-2H-pyrazin-1-yl)acetic acid (13.4 g, 41.6 mmol) was added to a stirred solution of potassium hydroxide (7.28 g, 110 mmol, assuming 15% water in the pellets) in water (600 ml). After degassing the resulting solution with argon, 10% Pd/C (6.3 g) was added and the mixture then stirred under a balloon of hydrogen. After 16 h, HPLC analysis showed that 1% of the starting material remained. The mixture was filtered through Celite and the filtrate was adjusted to pH 2 with 3N KHSO4 solution. The resulting precipitate was collected by filtration and washed with water. Drying for 16 h at 0.5 mm Hg gave 1-5 as a crystalline solid: 1H NMR (DMSO-d6) δ2.11 (s, 3 H, Me), 2.87 (t, J=7.6 Hz, 2 H, PhCH2), 3.53 (br s, 2 H, CH2NH), 4.68 (s, 2 H, CH2CO2), 6.68 (s, 1 H, pyrazinone H-5), 7.20-7.31 (m, 5 H, Ph), 8.16 (br s, 1 H, NH).

Provenance & Evidence