3-Dienoyl tetramic acid

Some phosphonates, e.g., (165), derived from tetramic acids have been prepared and shown to undergo normal olefination with ketones in work ultimately aimed at the synthesis of tetramic acid-containing natural products. A general method for the synthesis of 3-enoyl and 3-dienoyl tetramic acids, involving olefination with the phosphonate (166), has been reported. ... 

A Concise Approach to (-)-Tirandamycin A (2) and (+)-Tirandamycic Acid (3). Tirandamycin A (2) is a representative member of a novel class of naturally-occurring antibiotics that are characterized by the presence of an enolized 3-dienoyl tetramic acid moiety coupled with the unusual dioxabicyclo[3.3.1]nonane ring system. In addition to its antimicrobial activity, 2 inhibits bacterial DNA-directed RNA polymerase, and it interferes with oxidative phosphorylation. Early synthetic work in this area focused upon the preparation of (+)-tirandamycic acid (3), " which is a degradation product of tirandamycin A (2). The first major achievement in this area was Ireland s synthesis of 3 from D-glucose, but more recently 2 has also been prepared by total synthesisOur own investigations in this area culminated in a facile, asymmetric synthesis of 26, which played a pivotal role in Ireland s synthesis of 2 and Schlessinger s synthesis of 3. ... 

Two alternative methods for the preparation of phosphorus-activated tetramic acid reagents have recently been described.These reagents have served to provide a workable solution to the problem of construction of the dienoyl tetramic acid unit required for the synthesis of tirandamycin-A, - " ... 

Rosen, T., Fernandes, P.B., Marovich. M.A., Shen, L., Mao. J., and Pernet. A.G.. Aromatic dienoyl tetramic acids. Novel antibacterial agents with activity against anaerobes and Staphylococci. J. Med. Chem., 32, 1062. 1989. 

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