Optically active ketals, processes for their preparation and their use in the synthesis of apha-arylakanoic acids
申请人:ZAMBON S.p.A.
公开号:EP0158255A2
公开(公告)日:1985-10-16
Compounds of formula
wherein
Ar represents an optically substituted aryl group,
R represents a C,-C4 alkyl;
R, and R2, equal to or different from each other, represent hydroxy, O-M+, OR3 or N R4 R5 group,
R3 represents a C,-C24 alkyl, a C3-C6 cycloalkyl, a phenyl or a benzyl;
M+ represents the cation of an alkaline metal;
R4 and Rs, equal to or different from each other, represent a hydrogen atom, a C1-C4 alkyl, a C5-C6 cycloalkyl, a (CH2)n-CH20H group with n=1, 2 or 3, or R4 and R5 together are a group (CH2)m with m=4 or 5, a group -CH2-CH2R6-CH2-CH2- in which R6 is an oxygen atom, an N-H or N-(C1-C4) alkyl group;
X represents a chlorine, bromine or iodine atom, an hydroxy, acyloxy, alkylsulphonyloxy or arylsulphonyloxy group; the carbon atoms marked by an asterisk are both contemporaneously in the R or S configuration, are described.
The preparation of the compound of formula I by ketalization or by trans-ketalization with tartaric acid derivatives and their rearrangement into alpha-arylalkanoic acids is described too.
式中的化合物
式中
Ar 代表光学取代的芳基
R 代表 C,-C4 烷基;
代表羟基、O-M+、OR3 或 N R4 R5 基团、
R3 代表 C,-C24烷基、C3-C6 环烷基、苯基或苄基;
M+ 代表碱金属的阳离子;
R4和Rs,彼此相同或不同,代表氢原子、C1-C4烷基、C5-C6环烷基、n=1、2或3的(CH2)n-CH20H基团,或R4和R5一起是m=4或5的(CH2)m基团、R6为氧原子的-CH2-CH2R6-CH2-CH2-基团、N-H或N-(C1-C4)烷基;
X 代表氯、溴或碘原子,羟基、酰氧基、烷基磺酰氧基或芳基磺酰氧基;用星号标出的碳原子同时处于 R 或 S 构型。
此外,还介绍了通过与酒石酸衍生物酮化或反酮化以及将其重排为α-芳基烷酸来制备式 I 化合物的方法。