Benzyl Bromide → 2-Benzyl-6-bromo-2H-indazole

関与物質

反応手順

6-Bromoindazole (3.63 g, 18 mmol) was suspended in dioxane (15 mL) and benzyl bromide (2.65 mL, 22 mmol, 1.2 eq.) was added. The reaction was heated to reflux overnight, then allowed to cool to 80° C. after which point ethyl acetate (50 mL) added. The cake was broken up with a spatula and after stirring for 20 min, the solids were filtered off and washed with ethyl acetate, giving glossy white crystals of the hydrobromide salt of 2-benzyl-6-bromoindazole. These were suspended in ethyl acetate (100 mL) and shaken with saturated NaHCO3 (150 mL) until dissolution. The layers were separated and the aqueous layer was extracted with ethyl acetate (50 mL). The combined organic layers were concentrated to an off-white powder which was recrystallized from 66% ethanol (40 mL). Washing with water and drying in vacuo gave 2-benzyl-6-bromoindazole (3.30 g, 62%) as shiny white plates.

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