Cesium carbonate → 1-(2,2-Dimethoxyethyl)-5-iodo-1H-indazole

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-iodio-1H-indazole (8.28 g, 33.9 mmol) in DMSO (104 mL) was added 2-bromoacetaldehyde dimethyl acetal (7.9 mL, 68 mmol) and Cs2CO3 (44.1 g, 136 mmol). The reaction mixture was stirred at 40° C. for 18 h; then the reaction mixture was diluted with H2O (100 mL) and EtOAc (175 mL). The partitioned material was extracted with EtOAc (4×175 mL). The organics were washed with brine (2×100 mL), dried (Na2SO4), filtered, and concentrated. Purification by flash chromatography (silica gel, (hexanes with 0.1% Et3N)/(EtOAc with 0.1% Et3N), 100:0 to 90:10) yielded the title compound (4.49 g, 46%) as a light orange powder: 1H NMR (500 MHz, CDCl3) δ 8.07 (d, J=1.0 Hz, 1H), 7.92 (d, J=0.5 Hz, 1H), 7.60 (dd, J=9.0, 1.5 Hz, 1H), 7.28 (d, J=9.0 Hz, 1H), 4.71 (t, J=5.5 Hz, 1H), 4.44 (d, J=5.5 Hz, 2H), 3.33 (s, 6H).

Provenance & Evidence