In the commonly found siderophores like enterobactin and bacillibactin the hexandentate coordination of the iron (III) is achieved by 2,3-dihydroxybenzoic acid ligands (catechols), attached to a cyclic platform via an amide linkage. Several reports on the iron complexation properties of synthetic siderophores that incorporate the catecholamide (CAM) ligand system have appeared. A rare exception is petrobactin,PB, a citrate siderophore produced by Bacillus anthracis, the bacteria that is responsible for anthrax infections. This siderophore is unique in two ways. It is a called a stealth siderophore as its iron complex is not recognized by the human immune protein siderocalin, Scn. It also has 3,4- dihydroxycatechol ligands attached to a citrate unit for iron complexation. Our group is developing a new class of synthetic siderophores that incorporate the 3,4-dihydroxybenzoic acid moiety for investigation of their iron complexation and also allow us to unravel the structural uniqueness of petrobactin that makes it a stealth siderophore. In addition, we are also developing methodology to prepare the corresponding 3,4-dihydroxy sulfonamide analogs of petrobactin and other new synthetic siderophores that incorporate this sulfonamide ligand. This has led us to design and synthesize a new electrophilic 3,4-dihydroxybenzenesulfonyl synthon that can be readily attached to various platforms. The synthesis of a new aziridine reagent from N-(2-hydroxyethyl)-3,4-dimethoxybenzenesulfonamide and it utility in the synthesis of new classes of multidentate ligands will be described.

New methodology for the preparation of 3,4-dihydroxybenzenesulfonamide chelators for iron complexation

2019 Spring National Meeting

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