Synthesis and crystal structure of 4-amino-3-fluorophenylboronic acid

4-Amino-3-fluorophenyl boronic acid has been synthesized from 4-bromo-2-fluoroaniline by protecting the amine group and then carrying out a lithium-bromine exchange, followed by addition of trimethyl borate and then acidic hydrolysis. We obtained a 47% yield. We also measured the X-ray crystal structure. This derivative has a relatively low boronic acid pK(a) value of 7.8 when acetylated or attached to acrylamide hydrogels. It also contains a pendant amine which facilitates attachment to polymers, for example. We are using this compound to construct glucose sensing materials that operates at the physiological pH of bodily fluids. (C) 2003 Published by Elsevier Ltd.