p-Toluenesulfonic acid → 7-bromo-2-methyl-3-((E)-1-propyl-but-1-enyl)-2H-indazole

Participants

Reaction Steps

A solution of 4-(7-bromo-2-methyl-2H-indazol-3-yl)-heptan-4-ol (1.75 g, 5.38 mmol), 50 mL of toluene, and 4-toluenesulfonic acid (1.23 g, 6.46 mmol) was stirred at 110° C. for 20 h, then allowed to cool. A saturated aqueous NaHCO3 solution (50 mL) was added, and the mixture was extracted with three 30 mL portions of ethyl acetate. The combined organic layers were dried over MgSO4, filtered, and concentrated to a brown oil. Column chromatography (0→8% EtOAc/hexanes) afforded of 7-bromo-2-methyl-3-((E)-1-propyl-but-1-enyl)-2H-indazole (43; 1.47 g; 89%).

Provenance & Evidence