Hydrochloric Acid → HCID 22245074, compound

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Reaction Steps

Benzyl chloroformate (9.9 ml, ca. 66 mmol) in tetrahydrofuran (66 ml) was added dropwise with stirring to 5-aminoindazole (4.44 g, 33 mmol) in tetrahydrofuran (150 ml) and pyridine (12.0 ml, 150 mmol) at −5° C. The mixture was allowed to warm to room temperature, stirred for 4 h, and concentrated under vacuum. Ethyl acetate (100 ml) and water (150 ml) were added, and the aqueous layer was extracted with ethyl acetate (2×100 ml). The combined organic layers were washed with 0.3 N aq. HCl (2×100 ml), water, brine, and dried (MgSO4). Solvent was removed under vacuum to afford the crude product as a mixture of two regioisomers. MS (m/z): 402.1 [M+H]+. 0.3 M lithium hydroxide monohydrate in methanol (250 ml, ca. 75 mmol) was added. The mixture was stirred at room temperature for 45 min and then carefully acidified with 6 N aq. HCl until the pH of the solution was 2. The resulting product was filtered off, washed with water and dried under vacuum to afford the desired compound. Rt 4.2 min. MS (m/z): 268.1 [M+H]+. 1H NMR.

Provenance & Evidence