Process for the preparation of optically active alpha-arylalkanoic acids and intermediates thereof
申请人:ZAMBON S.p.A.
公开号:EP0158913A2
公开(公告)日:1985-10-23
A new enantioselective process is described for preparing optically active alpha-arylalkanoic acids by:
a) halogenation on the aliphatic carbon atom alpha to the ketal group, of ketals of formula
in which
Ar represents an aryl, optically substituted;
R represents a C1-C4 alkyl;
R, and R2, represent a hydroxy, a O-M+, OR3 or NR4R5
group; the carbon atoms indicated by an asterisk both
simultaneously are in (R) or (S) configuration.This reaction is
diastereoselective, so that a misture of alpha-haloketals is
obtained in which one of the two epimers prevails, and
generally strongly prevails, over the other.
b) rearrangement of the haloketals of formula
in which X is CI, Br or I to alpha-arylalkanoic acids in a single stage or in two successive stages, by way of esters of formula
The compounds (A) and (C) are all new compounds. The rearrengement step (b) may be performed under new, inventive conditions.
The esters of formula (C) have pharmacological activity analogous to that of the corresponding alpha-arylalkanoic acids.
介绍了一种通过以下方法制备光学活性α-芳基烷酸的对映体选择性新工艺:
a) 卤化式如下的酮的脂肪族碳原子α到酮基
其中
Ar 代表被光学取代的芳基;
R 代表 C1-C4 烷基;
R 和 R2 代表羟基、O-M+、OR3 或 NR4R5。
基团;星号表示的碳原子同时在
该反应具有非对映选择性。
该反应具有非对映选择性,因此可以得到α-卤代金属的畸变体。
该反应具有非对映选择性,因此可以得到α-卤代缩酮的混合物。
该反应具有非对映选择性,因此在得到的α-卤代金属错置物中,两种表聚物中的一种占优势,而且通常比另一种强。
b) 式中α-卤代金属的重排
式中 X 为 CI、Br 或 I 的卤代烃与 α-芳基烷酸在一个阶段或连续两个阶段的重排,通过式中的酯
化合物(A)和(C)均为新化合物。重整步骤 (b) 可在新的创造性条件下进行。
式(C)的酯类具有类似于相应α-芳基烷酸的药理活性。
CASTALDI, G.;CAVICCHIOLI, S.;GIORDANO, C.;UGGERI, F., J. ORG. CHEM., 52,(1987) N 14, 3018-3027
作者:CASTALDI, G.、CAVICCHIOLI, S.、GIORDANO, C.、UGGERI, F.