Analysis of the Key Intermediates for the Regioselectivity Control in the Methylation of the Manufacture of Clarithromycin by Reversed-Phase High Performance Liquid Chromatography
反相高效液相色谱分析克拉霉素合成工艺中区域选择性甲基化的关键中间体

2',4'-O-Bis(trimethylsilyl)erythromycin A-9-O-(1-isopropoxycyclohexyl)oxime (2',4'-TMS-EMIPCH) and 2',4'-O-bis(trimethylsilyl)-6-O-methylerythromycin A-9-O-(1-isopropoxycyclohexyl)oxime (2',4"-TMS-IPCH) are the key intermediates for manufacturing clarithromycin. A qualitative and quantitative method for baseline separation of E- and Z-isomers and related process substances has been established. A DIKMA-Inertsil ODS-3 column (150 mm x 4.6 mm i.d., 5 microm) was used. The column temperature was maintained at 40 degrees C. The mobile phase was CH3CN-H2O (95:5, v/v). The flow rate was 1.5 mL/min and the detection wavelength was UV 205 nm. Good linearities for E-2',4'-TMS-EMIPCH and E-2',4'-TMS-IPCH were obtained in the ranges of 6-60 microg (r = 0.9994) and 6-72 microg (r = 0.9998), respectively. The method described has also been demonstrated to work equally well on other 2',4'-O-bis(trimethylsilyl)erythromycin 9-oxime hydroxyl derivatives, which provided the criterion for optimizing the protective groups at 9-oxime hydroxyl position and the study of regioselectivity of methylation at the 6-OH position.