Synthesis And HPLC Analysis Of 2-Methozy-3-Pyridyl Boronic Acid And 3-Pyridyl Boric Acid

The new synthesis processes of 2-methoxy-3-pyridyl boronic acid and 3-pyridyl boric acid were investigated in this paper. The products were analyzed by HPLC, IRand 1HNMR.2-methoxy-3-pyridyl boronic acid was prepared with 2-methoxy-pyridine, diisopropylamine, tributylborate and butyllithium as the initial materials. Effects of the ratio of raw material, reaction temperature, reaction time and pH on the yield of the product were considered. The optimized process for the synthesis of 2 - methoxy -3-pyridyl boric acid was obtained. The isolated yield is 63.3%.The HPLC with UV detector at 270nm was applied to determination of 2-methoxy-3-pyridyl boronic acid on a C18 column using acetonitrile as a mobile phasa, with flow rate of 0.500ml/min. The RSD., linear concentration range of 2-methoxy-3-pyridyl boronic acid were 2.17﹪,1.00×10-5g/ml ¹0.00×10-5g/ml （r=0.9913）.3-pyridyl boric acid was prepared by using 3-bromine pyridine, butyllithium and tributylborate as main raw materials. Effects of the ratio of raw material, reaction temperature, reaction time and pH on the yield of the product were considered. The optimized process for the synthesis of 3-pyridyl boric acid was obtained as follows: reaction ratio of n（C5H4NBr） : n（n-BuLi） : n（B（OC4H9）3） = 1.0 : 1.2 : 1.2, the temperature was-65℃, and the reaction time was 60 min. The final yield was as high as 82.2%.The optimum chromatographic conditions were as follows : Kromstar ODS-1 C18 column（4.6mm×200mm, 5μm） was used and mobile phase was MeOH : H2O: TFA = 50 : 50 : 0.3, with flow rate of 0.600ml/min. The UV detector at 270nm was applied. The linearity was obtained over the range of 2.00×10^-4g/mL¹0.00×10^-4g/mL with r=0.9992. The relativestandard deviation （RSD） was 1.23%.