Synthesis And HPLC Analysis Of 2-thienyl Boronic Acid And 1-Naphthalene Boronic Acid

The new synthesis process of 2-thiophene boric acid and 1-naphthalene boronic acid was investigated in the paper.The purity and structure of product was characterized by HPLC,FTIR and HNMR.2-thiophene boric acid was prepared with Grignard reagent and tributyl borate.The experiment temperature,proportion,time,and pH was observed,better condition was:n?magnesium?:n?2-bromothiophene?:n?tributyl borate?=1.2:1.0:1.2,for 1.0h,experiment temperature was-55?.The pH is 2.0 by HCL,6.0 by NaCO₃.Production was furnished in 72.4%yield.The HPLC with UV detector at 245nm was applied to determination of 2-thiophene boric acid on a C₁₈ column?4.6mm×200mm,5?m?using acetonitrile as a mobile pHasa,with flow rate of 0.500ml/min.The RSD.,linear concentration range of 2-thiophene boric acid were 0.15?,5mg/L¹000mg/L?r=0.99993?.1-naphthalene boronic acid was synthesized by using 1-bromonaphthalene with tributyl borate,according to the n-butyl lithium reagent method.The effects of reaction temperature,reaction time,reactant molar ratio and pH value on the reaction yield were investigated.The optimal reaction condition for the synthesis of 1-naphthalene boronic acid was obtained as follows:the temperature is-70?,the time is 1.0h,the molar ratio is n?tributyl borate?:n?1-bromonaphthalene?:n?n-butyl lithium?=1.2:1.2:1.4,the pH is 6.0.Under the above reaction conditions,the yield of 1-naphthalene boronic acid reached94.6%.The optimum chromatographic conditions were as follows:Kromstar ODS-1 C₁₈column?4.6mm×200mm,5?m?was used and mobile phase was MeOH:H₂O:=7:3,with flow rate of 0.6ml/min.The UV detector at 275nm was applied.The linearity was obtained over the range of 0.05g/L⁰.5g/L with r=0.99943.The relativestandard deviation?RSD?was 0.21%.