反相高效液相色谱法分离2-(氟苯基)-5-甲基苯并恶唑和2-(氯苯基)-5-甲基苯并恶唑的位置异构体

基于商品化的普通色谱柱建立了2-(氟苯基)-5-甲基苯并恶唑和2-(氯苯基)-5-甲基苯并恶唑邻、间、对位置异构体的分离检测方法。色谱柱为Inertsil ODS-SP C₁₈(250 mm×4.6 mm, 5 μm),以乙腈(A)和水(B)为流动相,在60%A~80%A间线性梯度洗脱15 min,流速为1.5 mL/min,柱温40℃,检测波长为310 nm。在质量浓度为2~200 mg/L范围内,2-(氟苯基)-5-甲基苯并恶唑邻、间、对位的异构体、2-(氯苯基)-5-甲基苯并恶唑邻、间、对位的异构体具有良好的线性关系,6种化合物的检出限(S/N=3)依次为0.0307、0.0293、0.0315、0.0226、0.0237、0.0226 mg/L。该法既为5-甲基苯并恶唑与氟苯或氯苯碳氢活化偶联反应制备的异构体混合物提供了一个快速检测的方法,又为2-芳基苯并恶唑类异构体的分离检测提供了参考。

Reversed-phase high performance liquid chromatography separation of 2-(fluorophenyl)-5-methylbenzoxazole and 2-(chlorophenyl)-5-methylbenzoxazole positional isomers

The analytical method of 2-(fluorophenyl)-5-methylbenzoxazole ortho-, meta-, para-positional isomers and 2-(chlorophenyl)-5-methylbenzoxazole ortho-, meta-, para-positional isomers was developed with a commercial common liquid chromatography column. The separation was performed on an Inertsil ODS-SP C₁₈ column (250 mm×4.6 mm, 5 μm) at 40℃ with a linear gradient elution by mobile phases of acetonitrile (A) (from 60% to 80% within 15 min) and water (B) at a flow rate of 1.5 mL/min. The samples were detected by a diode array detector at 310 nm. Good linearities were obtained in the range of 2-200 mg/L for the six isomers. The limits of detection (LODs) (S/N=3) of 2-(fluorophenyl)-5-methylbenzoxazole ortho-, meta-, para-isomers and 2-(chlorophenyl)-5-methylbenzoxazole ortho-, meta-, para-isomers were 0.0307, 0.0293, 0.0315, 0.0226, 0.0237, 0.0226 mg/L, respectively. The method provides not only a rapid detection method for the preparation of the isomers through hydrocarbon activation coupling reaction between the 5-methylbenzoxazole and fluorobenzene or chlorobenzene but also a reference for the separation and detection of 2-arylbenzoxazole isomers.