Abstract The crystal structure of 2-(3-ethoxy-4-(methoxycarbonyl)phenyl) acetic acid ( RGA ), an important intermediate in the preparation of Repaglinide, has been carried out. Hydrogen bonds between the carboxylate groups link the molecules into dimers while weak C–H···π interactions link these dimers into a one-dimensional chain lying along the crystallographic b axis. 4-(Carboxymethyl)-2-ethoxybenzoic acid ( RGAA ), an impurity observed in the preparation of Repaglinide, has been simply synthesized by the hydrolysis of RGA under basic conditions. Hydrogen bonds between the carboxylate groups link the molecules into dimers while weak C–H···O interactions connect these dimers into a one-dimensional chain lying along the crystallographic c axis. The compound RGAA has also been characterized by FT-IR and UV–Vis spectra, and by 1 H NMR analysis. RGA : monoclinic, P 2 1 / n , a = 12.848(3) Å, b = 4.5539(10) Å, c = 22.328(5) Å, α = 90°, β = 101.703(5)°, γ = 90°, V = 1279.2(5) Å 3 . RGAA : monoclinic, P 2 1 / n , a = 14.0877(11) Å, b = 5.1814(3) Å, c = 14.5857(11) Å, α = 90°, β = 91.578(3)°, γ = 90°, V = 1064.26(13) Å 3 . The thermal behaviors and fluorescence properties of RGAA were also investigated. Graphic Abstract The crystal structures of one key intermediate of Repaglinide and its derivative have been characterized, where their luminescence properties and thermal behavior have been investigated.

中文翻译：

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瑞格列奈合成中关键中间体和重要杂质的制备、表征和晶体结构

摘要 2-(3-乙氧基-4-(甲氧基羰基)苯基)乙酸(RGA)是制备瑞格列奈的重要中间体，已对其晶体结构进行了研究。羧酸根之间的氢键将分子连接成二聚体，而弱的 C–H…π 相互作用将这些二聚体连接成沿结晶 b 轴的一维链。4-(羧甲基)-2-乙氧基苯甲酸 (RGAA) 是制备瑞格列奈时观察到的一种杂质，通过在碱性条件下水解 RGA 可以简单地合成。羧酸根之间的氢键将分子连接成二聚体，而弱的 C–H···O 相互作用将这些二聚体连接成沿晶体 c 轴的一维链。化合物 RGAA 还通过 FT-IR 和 UV-Vis 光谱以及 1 H NMR 分析进行了表征。RGA : 单斜晶系, P 2 1 / n , a = 12.848(3) Å, b = 4.5539(10) Å, c = 22.328(5) Å, α = 90°, β = 101.703(5)°, γ = 90 °, V = 1279.2(5) Å 3 。RGAA : 单斜晶系, P 2 1 / n , a = 14.0877(11) Å, b = 5.1814(3) Å, c = 14.5857(11) Å, α = 90°, β = 91.578(3)°, γ = 90 °, V = 1064.26(13) Å 3 。还研究了 RGAA 的热行为和荧光特性。图形摘要 表征了瑞格列奈及其衍生物的一种关键中间体的晶体结构，并研究了它们的发光性能和热行为。还研究了 RGAA 的热行为和荧光特性。图形摘要 表征了瑞格列奈及其衍生物的一种关键中间体的晶体结构，并研究了它们的发光性能和热行为。还研究了 RGAA 的热行为和荧光特性。图形摘要 表征了瑞格列奈及其衍生物的一种关键中间体的晶体结构，并研究了它们的发光性能和热行为。