申请人:Tanaka Daisuke
公开号:US20110190497A1
公开(公告)日:2011-08-04
The present invention provides a novel intermediate which enable to prepare tetrahydropyrrolo[1,2-a]pyrazin-4-spiro-3′-pyrrolidine derivatives such as Ranirestat being promising therapeutic agents for diabetic complications in a short process and in an economically advantageous and safe manner, and a process for preparing the same. That is, the present invention provides a process for preparing a compound of the following formula (I) wherein R
1
is an amino group protected with a protecting group, etc., and R
2
is a lower alkyl group, etc., comprising the following steps (1) and (2): (1) a step of converting a cyano group in a compound of the following formula (II) wherein n and m are each independently 0 or 1; provided when n is 0 and m is 1, then R
2
and R
3
are the same or different protecting groups for a carboxyl group; and when n is 1 and m is 0, then R
2
and R
3
are the same protecting groups for a carboxyl group; and R
1
is as defined above, into a carbamoyl group in the presence of divalent palladium compound(s), primary amide(s) and water; and (2) a step of cyclizing the product obtained in the step (1).
本发明提供了一种新型的中间体,能够以简短的过程、经济上可行且安全的方式制备四氢吡咯[1,2-a]吡嗪-4-螺-3'-吡咯烷衍生物,例如Ranirestat,这是一种对糖尿病并发症有治疗前景的药物,以及一种制备该中间体的方法。即,本发明提供了一种制备如下公式(I)化合物的方法,其中R1是带有保护基团的氨基,R2是低级烷基等,包括以下步骤(1)和(2):(1)将如下公式(II)化合物中的腈基转换为氨基甲酰基的步骤,其中n和m各自独立地为0或1;当n为0且m为1时,R2和R3是相同的或不同的羧基保护基团;当n为1且m为0时,R2和R3是羧基的相同保护基团;R1如上所述,该步骤中存在二价钯化合物、一级酰胺和水;(2)将步骤(1)中得到的产物环化的步骤。