Novel C2-Symmetrical Phenylboronic Acid Pinacol Esters with a Few Types of Linkers and Their Biological Activities

We report the preparation of new C 2 -symmetrical cyclic phenylboronic acid derivatives and their biological activities.New targeted C 2 -symmetrical molecules (1) were obtained in good to excellent yields by a primitive amide bond formation reaction using the reported method starting with amino-substituted phenylboronic acid pinacol esters 2. A few C 2 -symmetrical phenylboronic acid ester analogues such as 5 and 7 that have two urea groups in the linker junction were also prepared in order to evaluate antibacterial and antiviral activities.The results of a structure-activity relationship study are also described.Many bioactive C 2 -symmetrical bivalent molecules have been studied for the development of new agents to treat various infectious diseases or for new valuable ligands to treat diseases caused by dysfunctions of various receptors. 1-3A multivalent molecule is generally expected to show enhanced biological potential compared to that of the corresponding monovalent molecule. 4On the other hand, much attention has recently been paid to the design of synthetic receptors and detectors for carbohydrates in order to find new lectin-like molecules for recognition of saccharides (sugar chains). 57][8] From this point of view, we have been interested in boronic acids and related derivatives because many boronic acids (A) have a property to react with various 1,2-diol functionalities such as sugars and form cyclic derivatives