Sodium Chloride → 5-bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole-3-carbonitrile

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole-3-carbaldehyde (353 mg, 1.14 mmol) in MeCN (11.4 mL) was added triethylamine (223 uL, 1.60 mmol) and hydroxylamine hydrochloride (95.2 mg, 1.37 mmol). The reaction was heated to 60° C. for 16 h. The reaction mixture was then cooled to room temperature and additional triethylamine (541 uL, 3.88 mmol) was added, followed by trichloroacetyl chloride (306 uL, 2.74 mmol) dropwise. After stirring 30 min at room temperature, the reaction was heated to 65° C. for 20 h. The reaction mixture was then cooled to room temperature and poured into saturated aqueous sodium chloride (100 mL). The aqueous fraction was extracted with ethyl acetate (3×75 mL). The combined organic fractions were dried over sodium sulfate, filtered, and concentrated onto silica gel. Purification by ISCO chromatography (10 to 40% ethyl acetate:hexanes) afforded 301 mg (86%) of the title compound as a white solid. 1H NMR (400 MHz, DMSO-d6): δ 8.19 (d, J=1.8 Hz, 1 H), 7.97 (d, J=8.3 Hz, 1 H), 7.75 (dd, J=1.9, 9.0 Hz, 1 H), 6.07 (dd, J=2.5, 9.1 Hz, 1 H), 3.97-3.60 (m, 2 H), 2.40-2.17 (m, 1 H), 2.12-1.91 (m, 2 H), 1.84-1.64 (m, 1 H), 1.66-1.47 (m, 2 H); HPLC tR=3.73 min.

Provenance & Evidence