Sodium Hydroxide → 2-[(E)-1-[3-[1-(5,7-difluoroquinolin-6-yl)ethyl]-[1,2,4]triazolo[4,3-b]pyridazin-6-yl]ethylideneamino]oxyethanol

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Reaction Steps

To a suspension of 1-{3-[1-(5,7-difluoro-quinolin-6-yl)-ethyl]-[1,2,4]triazolo[4,3-b]pyridazin-6-yl}-ethanone (4.2 g, 11.9 mmol) in methanol (250 mL) was added 2-(aminooxy)ethanol hydrochloride (intermediate S) (2.70 g, 23.8 mmol). The mixture was stirred at rt overnight. LC-MS showed the reaction was complete. An aqueous 1N NaOH solution was added slowly until pH 8-9. The mixture was concentrated, extracted with EtOAc, washed with water and brine. The organic layer was dried over anhydrous Na2SO4, filtered, concentrated, and purified by gradient column chromatography (EtOAc:hexane=2:1, then 100% EtOAc, and then MeOH:EtOAc=1:12 as eluent) to afford 4.8 g (98%) of the title compound as a white solid. 1H-NMR (400 MHz, DMSO-d6) δ ppm 8.97 (dd, 1H), 8.44 (m, 1H), 8.25 (d, 1H), 7.64-7.70 (m, 2H), 7.59 (dd, 1H), 5.25 (q, 1H), 4.70 (t, 1H), 4.19 (t, 2H), 3.62 (dd, 2H), 2.02 (d, 3H), 1.88 (s, 3H). LCMS (method A): [MH]+=413, tR=5.09 min.

Provenance & Evidence