Synthetic approaches toward the marine alkaloid prenostodione

Total syntheses and antiproliferative activities of prenostodione and its analogues

A high-yielding total synthesis of the indole alkaloid prenostodione was completed in 4 steps and 44% overall yield from 1H-indole-3-carboxylic acid. The expedient syntheses of prenostodiones containing distinct substituents at the para position of the phenyl frame underscored the scope of this methodology. The cytotoxic activities of the tert-butyl esters of prenostodione analogues were tested using six tumor cell lines. Preliminary structure-activity studies revealed the importance of the identity of the aromatic substituent at the C-4 position for cytotoxic activity. The IC50 values of these compounds were found to compare satisfactorily with those of the commercially available drugs etoposide and cisplatin. Furthermore, the compounds with, respectively, -OMe (14d) and -NO2 (14f) groups at C-4 were more selective than these control compounds in PC-3, K-562, and MCF-7 cells. Also, computational studies were carried out to determine the ADMET profiles and passive membrane permeabilities of the compounds. The results suggested the promise of 14d and 14f as hit compounds for the development of new anticancer agents.

Pd-Catalyzed Dearomative Carboxylation of Indolylmethanol Derivatives

By using a new catalytic system (PdCl₂[P( n-Bu)₃]₂ in combination with ZnEt₂), various 3-indolylmethanol derivatives were successfully carboxylated with CO₂ (1 atm) via dearomatization of the indole nucleus, affording 3-methyleneindoline-2-carboxylates. In contrast, carboxylation of 2-indolylmethanol derivatives afforded unexpected doubly carboxylated products, which are useful synthetic precursors for biologically active compounds.

tert-Butyl 2,3-dihydro-1H-cyclopenta[b]indole-4-carboxylate

In the title molecule, C16H19NO2, all the non-hydrogen atoms except two of the C atoms of thetert-butyl group lie on a crystallographic mirror plane. No classical hydrogen bonds are observed. The crystal packing is influenced by weak π–π and C—H...π interactions.

Synthesis of the cyanobacterial metabolite nostodione A, structural studies and potent antiparasitic activity against Toxoplasma gondii

A total synthesis of the cyanobacterial natural product nostodione A is reported involving a convergent, diversity-oriented route, enabling the assembly of a mini-library of structural analogues. The first single crystal X-ray structural determination on a member of this series is reported along with SAR studies identifying potent inhibitors of invasion and replication of the parasitic protozoan Toxoplasma gondii.

Total synthesis of the cyanobacterial metabolite nostodione A: discovery of its antiparasitic activity against Toxoplasma gondii

A diversity-oriented total synthesis of nostodione-A and analogues and their antiparasitic activity againstToxoplasma gondiiis reported.