3-chloro-1H-indazol-5-carbaldehyde synthesis

Yield:1086391-03-8 97%

Reaction Conditions:

with N-chloro-succinimide in acetonitrile at 20; for 12 h;Reflux;

Steps:

43.A

Example 43A3 -Chloro- 1 H-indazole-5 -carbaldehyde To a solution of 4.0 g (27.4 mmol) 1 H-indazole-5 -carbaldehyde [preparation described in US 2005/0227968-A1 (Intermediate I)] in acetonitrile (116 ml) were added 4.2 g (31.5 mmol) N- chlorosuccinimide at room temperature. The resulting solution was stirred under reflux for 12 h. The mixture was then concentrated under reduced pressure yielding a solid precipitate. This material was triturated with water, filtered, and dried under high vacuum for 12 h to give the title compound (4.8 g, 97% of th.) as a white solid. 1H-NMR (400 MHz, DMSO-Ci6): ? = 13.76 (s, IH), 10.06 (s, IH), 8.37 (s, IH), 7.92 (d, IH), 7.72 (d, IH) ppm.

References:

WO2009/149837,2009,A1 Location in patent:Page/Page column 78-79