A common heterocyclic compound, 19745-07-4, name is 2,5-Dichloropyrazine, molecular formula is C4H2Cl2N2, 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. 19745-07-4.
A mixture of K2C03 (3.4 g, 0.24 mmol), 2,4-difluoro-3-hexyloxy-5-(2-pyridyl)phenyl boronic acid (2.04 g, 6.1 mmol) and 2,5-dichloropyrazine (719 mg, 2.5 mmol) in a mixture of water (20 ml_), toluene (40 ml_) and ethanol (2 ml_) was deoxygenated by bubbling N2 through the mixture for 20 minutes. Pd(PPh3)4 (250 mg, 0.24 mmol) was then added and the mixture was heated under refluxed for 15 hours. Brine (40 ml_) was added and the phases were separated. The aqueous layer was extracted with ethyl acetate (3 x 20 ml_). The combined organic layers were dried over MgS04, filtered and evaporated to dryness. The product was purified by column chromatography (Si02, Petroleum ether/EtOAc, from 9/1 to 6/4). Colourless solid (630 mg, 38percent). 1 H NMR (400 MHz, CDCI3) delta 9.15 (d, 1 H, J = 2.0 Hz), 8.74 (ddd, 2H, J = 1.2 Hz, J = 5.2 Hz, J = 6.4 Hz), 8.39 (dd, 2H, J = 8.4 Hz), 7.78 (m, 4H), 4.23 (t, 4H, J = 6 Hz), 1.83 (q, 4H, J = 7.2 Hz), 1.34 (m, 4H), 1.36 (m, 8H), 0.90 (t, 6H, J = 7.2 Hz). 13C NMR (100 MHz, CDCI3) delta 152.40, 150.05, 146.85, 144.58, 144.46, 136.63, 125.49, 125.31 , 124.40, 124.32, 122.86, 121.34 (m), 75.57, 31.32, 30.10, 25.46, 22.68, 14.13.
The synthetic route of 2,5-Dichloropyrazine has been constantly updated, and we look forward to future research findings.
Reference:
Patent; UNIVERSITY OF NORTHUMBRIA AT NEWCASTLE; KOZHEVNIKOV, Valery; LANOE, Pierre-Henri; WO2014/23972; (2014); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem