Triethylamine hydrochloride → 6-Chloro-7-phenyl-3-(pyrazin-2-yl)-1,2,4-triazolo[4,3-b]pyridazine

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Reaction Steps

The product from Example 1 step b) (1 g, 4.46 mmol) was suspended in xylene (25 ml) with pyrazine-2-hydrazide (0.74 g, 5.35 mmol) and triethylamine hydrochloride (0.61 g, 4.46 mmol) and the reaction mixture was heated at reflux for 2 days. The solvent was removed under high vacuum, and the residue was dissolved in dichloromethane, basified with sodium bicarbonate and the aqueous extracted with dichloromethane (2×150 ml). The combined organic layers were washed with brine, dried (MgSO4), filtered and evaporated. The residue was purified by silica gel chromatography using 0-40% ethyl acetate in dichloromethane as eluent to give the required product (0.249 g). 1H NMR (250 MHz, DMSO) δ 7.56 (5H, m), 8.43 (1H, s), 8.87 (1H, d, J=2.5 Hz), 8.96 (1H, d, J=2.5 Hz), 9.49 (1H, d, J=2.5 Hz); MS (ES+) m/e 309 [MH+].

Provenance & Evidence