(Z)-2-N-Acylamino-3-pyridyl-acrylic acids and their esters were prepared by partially known procedures and hydrogenated in the presence of HBF4 to the corresponding optically active 2-N-acetyl-(or benzoyl-)-3-(3- or 4-pyridyl)-alanines or analogous methyl esters with enantiomeric excesses up to 90%. The rhodium complexes of PROPRAPHOS, 6a,b, or of O,N-bis(diphenylphosphino)-2-exo-hydroxy, 3-endo-methylamino-norbor-nane
通过部分已知的方法制备(Z)-2 - N-酰基
氨基-3-
吡啶基-
丙烯酸及其酯,并在HBF 4存在下将其氢化成相应的旋光的2- N-乙酰基-(或苯甲酰基-)-。 3-(3-或4-
吡啶基)-丙
氨酸或对映体过量最高达90%的类似甲酯。PROPRAPHOS,所述的
铑络合物6A,B,或ö,ñ -双(
二苯基膦基)-2-外-羟基,3-内型-甲基
氨基- norbor-娜内,6C,作为手性催化剂已经在HBF的存在下被使用4生成相应的
吡啶鎓盐。重结晶的
氨基酸衍
生物的脱酰作用或游离
氨基酸的进一步重结晶产生对映体纯的D-和L-
吡啶基丙
氨酸。