Chloride 2-chloropyridinium 1-oxide → Ethyl 1-{2-[(1-hydroxy-2-pyridyl)amino]ethyl}-1h-indazole-5-carboxylate

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Reaction Steps

Ethyl 1-(2-aminoethyl)-1H-indazole-5-carboxylate (584 mg, 2.5 mmol, prepared as in step B), was added to dry n-butanol along with 2-chloropyridine-N-oxide hydrochloride (847 mg, 5.1 mmol) and anhydrous sodium bicarbonate (850 mg, 10.1 mmol). The reaction mixture was vigorously stirred and heated at 100 C for 21 hr. Additional aliquots of 2-chloropyridine-N-oxide hydrochloride (847 mg, 5.1 mmol) and anhydrous sodium bicarbonate (850 mg, 10.1 mmol) were added and heating continued for 24 hours. The reaction was cooled and filtered and the filtrate concentrated. The residue was purified by flash chromatography (5% methanol-dichloromethane) and the product fractions concentrated to afford the product as an orange solid (358 mg, 44%). LRMS (ES): 327.1 ([M+H]+, 100%), 653.3 ([2M+H]+, 40%) 1HNMR (600.1343 MHz, CDCl3): 8.44 (s, 1H), 8.12 (s, 1H), 7.97 (d of t, 2H), 7.56 (bs, 1H), 7.45 (d, 1H), 7.06, (m, 1H), 6.45 (m, 1H), 6.35 (t, 1H), 4.68 (t, 2H), 4.37 (q, 2H), 3.90 (q, 2H), 1.39 (t, 3H).

Provenance & Evidence