2,3,4,5,6-Pentabromobenzoic Acid

Pentabromobenzoate is a useful fragment in organic synthesis and in coordination chemistry. Among known synthetic approaches to pentabromobenzoic acid (PBA), we have assessed and identified exhaustive bromination of benzoic acid by using 1.3-dibromoisocyanuric acid in concentrated H2SO4 solution as the most efficient method for the preparation of PBA on a multigram scale. As the crude bromination product is typically contaminated with 3,4,5,6-tetrabromobenzoic acid (TBA) and pentabromobenzene, C6Br5H, a simple purification protocol for preparation of analytically pure PBA has been developed. The molecular structure and crystal packing of PBA established by single-crystal X-ray diffractometry suggests a pattern of H-bonding and halogen bonding in solid state.