3,4-dihydro-2H-pyran → 3-bromo-1-(oxan-2-yl)-1H-indazole

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-bromo-1H-indazole (500 mg) synthesized according to a method of the literature (V> Auwers, et al., J. Prakt. Chem., 1924, 314) in toluene (25 mL, manufactured by Wako Pure Chemical Industries, Ltd.), 3,4-dihydro-2H-pyrane (640 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) and p-toluenesulfonic acid monohydrate (10 mg, manufactured by Wako Pure Chemical Industries, Ltd.) were added, and the mixture was heated for one hour at 80° C. The reaction solution was cooled to room temperature, and then a saturated aqueous solution of sodium hydrogen carbonate (10 mL) was added thereto. The mixture was extracted with ethyl acetate (3×20 mL), washed with brine (40 mL), and dried (MgSO4), and the solvent was evaporated. The resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate=9:1), to give 570 mg of the title compound. LC-MS: HPLC retention time 4.93 minutes, m/z 281 (M+H), condition B-1.

Provenance & Evidence