Patent ID: 6197996
Filing Date: 2001-03-06
Classification: C07C

Abstract:
A process for preparing an optically active carnitine ester represented by formula (I): ##STR7##wherein R represents a lower alkyl group having two or more carbon atoms; and X represents a halogen atom,which process consists essentially of asymmetrically hydrogenating a .gamma.-trimethylammonium-3-oxabutanoic ester halide represented by formula (II): ##STR8##wherein R and X are as defined above,in the presence of a ruthenium-optically active phosphine complex as a catalyst,and then recovering the optically active carnitine ester represented by formula (I) which has been formed, wherein said ruthenium-optically active phosphine complex is selected from the group consisting of a compound represented by formula (III):Ru.sub.x H.sub.y Cl.sub.z (R.sup.1 --BINAP).sub.2 (Q).sub.p (III)wherein R.sup.1 --BINAP represents a tertiary phosphine represented by formula (IV): ##STR9##R.sup.1 represents a hydrogen atom, a methyl group or a t-butyl group;Q represents a tertiary amine; y is 0, x represents 2, z represents 4, and p represents 1;a compound represented by formula (VI): ##STR10##wherein R.sup.1 --BINAP is as defined above; and R.sup.2 represents a lower alkyl group or a trifluoromethyl group; and a compound represented by formula (VII):[Ru(R.sup.1 --BINAP)MCl.sub.k ].sub.l X.sub.m.sup.1 (VII)wherein R.sup.1 --BINAP is as defined above; M represents Zn, Al, Ti or Sn; X.sup.1 represents N(C.sub.2 H.sub.5).sub.3 or CH.sub.3 CO.sub.2 ; in the case that X.sup.1 represents N(C.sub.2 H.sub.5).sub.3, l is 2 and m is 1, and when M represents Zn, then k is 4, when M represents Al, then k is 5, and when M represents Ti or Sn, then k is 6; and in the case that X.sup.1 represents CH.sub.3 CO.sub.2, l is 1 and m is 2, and when M represents Zn, then k is 2, when M represents Al, then k is 3, and when M represents Ti or Sn, then k is 4.