HCID 23543228, Verbindung → 8-Butyl-6-oxo-2-(2-methoxyphenyl)-imidazo[1,2-a]pyrazine

The product from Step 1.d. (compound v where R3 is n-butyl, R4 is 2-methoxyphenyl, and R5 and R6 are H) (11.5 g, 23.9 mmol) was dissolved in HOAc (100 ml) containing 10% Pd on carbon catalyst (500 mg) and hydrogenated under 50 psi of H2 for about 3 hours at room temperature. The catalyst was removed by filtration through a 3 cm pad of diatomaceous earth and the filtrate was warmed at about 70° C. for about 2 hours. The mixture was concentrated to a solid under reduced pressure, dissolved in CH2Cl2 (100 ml) and washed with saturated NaHCO3 solution (125 ml). The CH2Cl2 layer was dried over Na2SO4, filtered and 275 ml hexanes was added. Product was filtered off and dried to constant weight to yield 6.21 g (87%) of product, m.r.=200–202° C., NMR (300 MHz, DMSO-d6, 30° C.) 8.5–8.6 (1H s), 8.0–8.1 (1H, d), 7.4–7.6 (1H, s), 7.1–7.3 (1H, t), 7.0–7.1 (1H, d), 6.9–7.1 (1H, t), 4.55–4.8 (2H, q), 4.55–4.7 (1H, t), 3.8–4.0 (3H, s), 1.75–1.95 (2H, m), 1.1–1.5 (4H, m), 0.8–0.9 (3H, t).