(±)-Talaroindolenes A and B: Spiro-Ergot Alkaloid Enantiomers with a 5/6/6/6/5/5 Hexacyclic System and
Hanxiao Zeng1,2, Yongfei Zhang1,2, Shenglan Yang1,2
1Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China.
Abstract:
Chemical investigation of fungus Talaromyces sp. TJ403-AL05 led to the isolation of (±)-talaroindolenes A (1a/1b) and B (2a/2b), two pairs of spiro-ergot alkaloid enantiomers featuring a 5/6/6/6/5/5 hexacyclic skeleton defined by a spiro[2-oxa-7,15-diaza-pentacyclo[12.2.1.11,8.03,7.012,18]octadecane-13,1'-[2]oxacyclopentane] core. Extensive spectroscopic analysis, X-ray crystallography and ECD calculation were used to determine the structure and absolute configuration of each enantiomer after chiral resolution. Additionally, 2b exhibited significant cardioprotective effect on oxygen-glucose deprivation (OGD)-damaged H9C2 cells by preserving mitochondrial membrane potential and modulating the mRNA levels of Bax and Bcl-2.
Related Concept Videos
Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Stereoisomerism of Cyclic Compounds
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Naming Enantiomers
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Properties of Enantiomers and Optical Activity


