Synthesis and characterization of norfloxacin biomonomer Shengxiong DONG 1, 2, 3 ;Qiaoping CHEN 1 ;Hongfang XIE 1 ;Jianhua HUANG 1, 2, 3 ; 1. Department of Chemistry and Environmental Science, Ningde normal University, Ningde , China ; 2. College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou , China ; 3. Fujian Provincial Key Laboratory of Polymer Materials, Fuzhou University, Fuzhou , China ; Fig.1 In the second step, NF1 3.8 g and triethylene glycol TEG was solved in 50 mL of dichoromethane within a glass vessel. Then, some EDC.HCl and some DMAP were added as dehydrating agent and as catalytic agent, respectively. The molar ratio of the materials was 2 ∶ 1 ∶ 5 ∶ 1 for NF1TEGEDC.HClDMAP. The mixture was stirred at the room temperature. The solids were solvent completely in 5 min. The system remained clear and pale yellow throughout the reaction. One week later, the solution was vacuum distilled. The achieved solid was washed with the mixture of methanol and tricloromethane. The volume ratio of the mixture was 15 ∶ 1 for methanoltricloromethane. The resulting product abbreviated as NF2 was dried in a vacuum oven at 50°C overnight. The process of reaction can be considered as Eq. 2. Fig.2 In the third step, NF2 2 g was dissolved in 50mL of tricloromethane. Then, 0.5 mL of trifluoroacetic acid and 0.5 mL of H 2 O was added. The mixture was stirred for 4 h at room temperature. The product that was the final product named norfloxacin biomonomer NFB was precipitated in the system gradually. At the completion of the reaction, the system was filtrated. Wash the solid with trichloromethane and dry it at the temperature of 50°C overnight. The process of reaction can be considered as Eq. 3. Fig.3 Characterization High- performance liquid chromatography A high-performance liquid chromatography HPLC system Prostar 210, Varian, USA was used to analyze the purity of the product and intermediate products. C18 steel cartridge column Inertsil ODS-SP and a UV detector were used in the instrument. The mobile phase consisted of 90% methanol and 10% H 2 O. The mobile phase was degassed using an ultrasound machine. The standards were prepared by dissolving the sample fee in 2 mL of mobile phase to yield concentrations between 1 and 10 mg·L -1. The resulting product was dried in a vacuum oven at 50°C overnight. The 20 μL of the sample solution was injected with a mobile phase flow rate of 1.0 mL·min -1. Data were recorded and processed on a computer. Fourier transform infrared spectrometer The product and intermediate products were monitored by Fourier Transform Infrared Spectrometer FTIR with a Thermo Nicolet Nexus 870 spectrometer using a DTGS KBr detector on West Georgia Laboratories Polytetrafluoroethylene PTFE IR cards. Mass spectrometry Mass spectrometry MS was used to elucidate the molecular structure and chemical composition of the product and intermediate products. The mass spectrometric investigations were carried out with the mass spectrometer of 1100LCMSD Trap XCT MI Agilent, USA. The method of ionization was electrospray ionization APCI. Results and discussion High-performance liquid chromatography The figures in Figs. 1-4 showed the results of HPLC. It showed that the retaining times of the NF, NF1, NF2, and NFB were 3.64, , , and min, respectively. It is observed in Fig. 1 that the final product and intermediate products were well purified. Fig.4 HPLC result of NF Frontiers of Chemical Science and Engineering,2011,5(1), Doi: /s