Electric Literature of 109838-85-9, These common heterocyclic compound, 109838-85-9, name is (R)-2-Isopropyl-3,6-dimethoxy-2,5-dihydropyrazine, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
To a stirred solution containing 0.62 mL (650 mg, 3.53 mmol) of Schoellkopf’s reagent in 10 mL of anhydrous THF at -78 °C was added 0.45 mL (308 mg, 4.82 mmol) of 2.5 M BuLi. The reaction mixture was stirred at -78 °C for 30 min under argon and then a solution containing 1.03 g (3.21 mmol) of 3-(chloromethyl)-1-tosyl-1H-pyrrolo[2,3-b]pyridine (4) in 10 mL of anhydrous THF was added. The reaction mixture was stirred for 1 h under argon at -78 °C, then diluted with 50 mL of satd aq NH4Cl and extracted with two 50-mL portions of EtOAc. The combined organic phase was dried (MgSO4) and concentrated under diminished pressure. The residue was purified by chromatography on a silica gel column (10 * 2 cm). Elution with 2:1 hexanes/ethyl acetate gave 3-(((2S,5R)-5-isopropyl-3,6-dimethoxy-2,5-dihydropyrazin-2-yl)methyl)-1-tosyl-1H-pyrrolo[2,3-b]pyridine (5) as a yellow oil: yield 783 mg (52percent); silica gel TLC Rf 0.15 (4:1 hexanes/ethyl acetate); 1H NMR (CDCl3, 400 MHz) delta 0.51(d, 3H, J = 6.8 Hz), 0.78 (d, 3H, J = 8 Hz), 1.99-2.03 (m, 1H), 2.22 (s, 3H), 3.07-3.12 (m, 3H), 3.57 (s, 3H), 3.60 (s, 3H), 4.22-4.25 (m, 1H), 7.02-7.05 (m, 1H), 7.13 (d, 1H, J = 8 Hz), 7.36 (s, 1H), 7.74 (dd, 1H, J = 8.0 and 1.6 Hz), 7.87 (d, 2H, J = 8.4 Hz) and 8.29 (dd, 1H, J = 4.8 and 1.6 Hz); 13C NMR (CDCl3, 400 MHz) delta 16.4, 18.8, 21.5, 29.1, 31.3, 52.1, 52.3, 55.5, 60.4, 114.9, 118.3, 123.7, 124.6, 127.5, 128.2, 129.5, 135.5, 144.6, 144.8, 147.1, 161.8 and 164.0; mass spectrum (APCI), m/z 469.1921 (M+H)+ (C24H29N4O4S requires m/z 469.1909).
The synthetic route of 109838-85-9 has been constantly updated, and we look forward to future research findings.