Inherently chiral dialkyloxy-calix[4]arene acetic acids with asymmetric placement of substituents on the lower rim of the macrocycle were first studied as enantiodiscriminating additives to the mobile phase MeCN/H₂O/HCOOH (75/25/0.02 by volume) in the high-performance liquid chromatography (HPLC) separation of d,l-alanine and d,l-valine on the achiral stationary phase ZORBAX Original CN. The dependence of enantio-binding properties on the position of alkyl groups is demonstrated. The highest resolution (1.65) and enantioselectivity (1.80) were obtained for the 1,2-dipropyloxy-calix[4]arene acetic acid.

中文翻译：

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固有手性二烷氧基杯[4]芳烃乙酸作为对映体鉴别添加剂用于 d,l-氨基酸的高效液相色谱分离

_{作为流动相 MeCN/H 2} O/HCOOH（体积比为 75/25/0.02）的对映体鉴别添加剂，首先研究了在大环下缘不对称放置取代基的固有手性二烷氧基杯[4]芳烃乙酸。 d , l-丙氨酸和d , l-缬氨酸在非手性固定相ZORBAX Original CN上的高效液相色谱（HPLC）分离。证明了对映体结合性质对烷基位置的依赖性。对于 1,2-二丙氧基-杯[4]芳烃乙酸，获得了最高分辨率 (1.65) 和对映选择性 (1.80)。