Facile Stereoselective Total Synthesis Of Decarestrictine_J Diplodialide C and D and _Tetrahydropyrenophorol

Abstract

Macrolides are a class of antibiotics that consist of a large macrocyclic lactone ring attached to deoxy sugars. These antibiotics are bacteriostatic in nature and act by inhibiting protein synthesis of bacteria. These are obtained mainly from certain actinomycetes genus, such as Streptomyces and related species. The original macrolide complex, erythromycin A, was isolated in 1952 as a natural product of Saccharopolyspora erythraea (formerly Streptomyces erythreus). Other examples include clarithromycin, azithromycin, telithromycin, cethromycin, etc. Macrolides structurally contain three characteristic parts in every molecule, that is, a macrocyclic lactone ring, multiple ketone and hydroxyl group, and two deoxy sugars attached by glycosidic bond. According to the carbon number of lactone ring, macrolides are classified into several types. That is, 12-membered ring, 13-membered ring, 14-membered ring, 15- membered ring, 16-membered rings, etc. Out of these, most of the antibiotic drugs comprised of 14-membered and 16-membered lactone rings. newlineMacrolides show interesting activity in cell line tests with HEP-G2 liver cells due to an inhibitory effect on cholesterol biosynthesis. These macrolides inhibit the biosynthesis of cholesterol. Due to the promising biological activity and the impressive structural features of macrocyclic lactones are well-represented in nature as both homo and heterodimers and offer a wide variety of skeletons, ring sizes, and functional groups. Natural products with macrodiolide frameworks are also known to exhibit a wide range of biological properties including antibiotic, antifungal, anthelmintic, phytotoxic and antileukemic activities. newlineMedium-sized-ring systems, those containing 8 to 11 atoms in the ring are a subject of continuous interest to organic chemists, as they form the core of many bioactive natural products. The construction of macrocyclic structures is always a recurrent and challenging problem in synthetic organic chemistry.