|
製備高效率對掌性靜相填充材料用以離析胺基酸、胺基醇、胺類及羧酸類鏡像異構物
，並確認對掌性離析機制是本論文的主要目的。利用三種胺基酸與四種不同異氰酸酯
反應所得之衍生物，以離子鍵結或共價鍵結製備一系列具結構相關性的對掌性靜相作
為高效液相層析儀管柱填充材料，用以離析各種鏡像異構物。更經由各靜相之層析性
能的比較，進而確認靜相中各種官能基在對掌性辨認中之貢獻。
本研究中所製備之十二種對掌性靜相中，除含苯胺基甲醯-(S)- 苯甘胺酸之共價鍵結
型對掌性靜相外，對所選定的四類溶質之一部分或全部都具有離析的能力，其中對於
某些溶質更具有前所未有的離析效果，在實用上有相當高的應用價值。由各靜相之層
析性能的比較得知：離子鍵結型一般較其相對的共會鍵結型對掌性靜相有較佳的對掌
性辨認能力。含基的靜相比硫基之靜相在對掌性離析上具顯著的優越性。具有單
一不對稱中心之靜相中，以含苯胺基甲醯-(S)- 苯甘胺酸之對掌性靜相具有最佳之對
掌性辨認能力，而含有兩個不對稱中心之含(S)-苯基乙胺基甲醯之(R)-或(S)-苯甘胺
酸衍生物的離子鍵結型對掌性靜相顯現出更優越而廣泛的辨認能力，對於胺基酸、胺
基醇、胺類及羧酸等受測試溶質鏡像異構物均可高效率的加以離析，尤其是常用於消
炎、解熱、鎮痛藥之2-異丁基苯基丙酸（ibuprofen） 在該對掌性靜相離析之選擇因
素遠大於前人在其他類型對掌性靜相離析之值。
從離析的層析行為進一步探究此系列的靜相與受測溶質間的對掌性辨認模式，得知本
研究所設計之對掌性靜相中，具有提供立體選擇性作用力者，除了立體效應，基鍵
結的氫鍵作用力與芳香基的π－π作用力外，基兩端同時各接一個不對稱中心時對
於不同結構類型之溶質更能發揮對掌性辨認能力。有關本系列對掌性靜相之對掌性離
析辨認模式也將於本論文中提出討論。
///////
A series of twelve chiral stationary phases (CSPs) was prepared with
arylcarbamyl derivatives of amino acids either ionically or covalently
bonding through 3-aminopropyltriethoxysilane onto silica gel.
These chiral stationary phases, except the CSP which contains covalently
bonding phenylcarbamyl-(S)-phenylglycine, provide recognition ability for
the separation of enantiomeric amide derivatives of amino acids, amino
clcohols, amines and acids by high-performance liquid chromatography
(HPLC). However, the magnitude of the recognition ability is varied with
the fine structures. Generally speaking, the CSPs of ionically bonding
derivatives are more effective than the resemble CSPs of covalently
bonding derivatives for chiral resolution of enantiomeric solutes.
Moreover, the CSP which contains urea funcitional group has better
recognition ability than the resemble one containing thiourea funcitional
group for the resolution of the same enantiomers. Among the nine CSPs of
which contain one chiral moiety, the one with ionically bonding
benzylcarbamyl-(S)-phenylglycine shows best recognition ability towards
all types of test solutes. Moreover, the CSPs containing two chiral
moieties were found to perform better than the resemble CSPs containing
only one chiral moiety for effective resolution of the four types of
enantiomeric solutes. Thus, among the series of twelve chial stationary
phases, the CSPs bearing ionically bonding
(S)-phenylethylcarbamylphenylglycine show best performance in chiral
resolution performance for racemic amino acids, amino alcohols, amines and
acids. Most of all the selectivity factor for the resolution of
enantionmeric ibuprofen, which is used as an nonstereoidal
anti-inflammatory antipyretic analgesic, is better than any observed in
the literature.
Based on the chromatographic behaviors, the stereoselectivity of the
prepared stationary phases are attributed to various factors, such as the
steric effect, the hydrogen-bonding interaction of urea linkage, and the
π-πinteractions of aromatic rings. Moreover, the chiral recognition
ability of CSP is enhanced when each nitrogen atom of urea functional
group on the structure of CSP is attached with a chiral center. A chiral
recognition model for the enantiomers separation on these chiral
stationary phases was proposed.
|