1- (2-fluoro-benzyl) -1H- pyrazolo 3,4-b pyridine-3-formamidine process for the synthesis of hydrochloric acid salt

摘要

The present invention relates to a chemical synthesis method, in particular a key intermediate for synthesizing Kochi thromboembolic disease drugs Riociguat (Riociguat) 1- (2- fluorobenzyl) -1H- pyrazolo [3,4-b] pyridine - It relates to a process for the synthesis of 3-formamidine hydrochloride. The present invention is 3-iodo -1H- pyrazolo [3,4-b] pyridine as the raw material; is reacted with fluoro-benzyl bromide are to give compound 10; compound 6 to the compound 10 is reacted with zinc cyanide The resulting by; the compound 6 Sodium methoxide, ammonium chloride, to give the compound 8 is reacted with acetic acid and methyl alcohol; the compound 8 is reacted with hydrochloric acid gas 1- (2-fluorobenzyl) -1H- pyrazolo I get [3,4-b] pyridine-3-formamidine hydrochloride. This synthesis method, the raw material can be inexpensive and readily available, high yield, has a characteristics such as moderate reaction conditions, to allow large-scale production. .BACKGROUND