HETEROCYCLES

■ Novel Trivalent C3-Symmetrical Phenylboronic Acid Pinacol Esters and Their Biological Evaluation

Makoto Furutachi, Saho Fuchigami, Kenta Ako, Saho Goto, Toshiaki Gondo, Mai Takuse, Moeko Yoshida, Kazumi Yokomizo, Jian-Rong Zhou, Aya Matsunaga, Nozomi Hiraga, Nobuhiro Kashige, Fumio Miake, and Kunihiro Sumoto*

*Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan

Abstract

We report the preparation of newly designed trivalent C3-symmetrical cyclic phenylboronic acid derivatives constructed on a symmetrical benzene or a cyclohexane ring. The synthesis of these C3-symmetrical molecules 4 was accomplished by an amide bond formation reaction using amino-substituted phenylboronic acid pinacol esters 2 and C3-symmetrical benzene-1,3,5-tricarboxylic acid trichloride 3a or cyclohexane-1,3,5-tricarboxylic acid trichloride 3b in the presence of Et3N. We confirmed that this procedure is conventionally applicable to the preparation of targeted C3-symmetrical cyclic boronic acid derivatives 4 in good to excellent yields. We also report the results of biological evaluation of the prepared compounds.