No abstract

A range of substituted N-alkylisatins were synthesized and their cytotoxicity evaluated against several cancer cell lines in vitro. SAR studies indicated that the introduction of an aromatic ring with a one or three carbon atom linker at N1 enhanced the activity from that of the allyl, 2'-methoxyethyl, and 3'-methylbutyl N-substituted isatins. Furthermore, electron-withdrawing groups substituted at the meta or para position of the ring were favored over the ortho orientation. Of the 24 compounds screened, nine displayed sub-micromolar IC50 values and in general demonstrated greater selectivity toward leukemia and lymphoma cell lines over any of the carcinoma cell lines tested. 5,7-Dibromo-N-(p-methylbenzyl)isatin (6) was the most active compound, inhibiting the metabolic activity of both U937 and Jurkat cancer cell lines at 0.49 muM. Various N-alkylisatins were also found to dramatically alter lymphocyte morphology, destabilize microtubules, inhibit tubulin polymerization, induce G2/M cell cycle arrest, and activate the effector caspase-3 and -7.

No abstract

Density functional theory calculations indicate that van der Waals fullerene dimers and larger oligomers can form interstitial electron traps in which the electrons are even more strongly bound than in isolated fullerene radical anions. The fullerenes behave like "super atoms", and the interstitial electron traps represent one-electron intermolecular σ-bonds. Spectroelectrochemical measurements on a bis-fullerene-substituted peptide provide experimental support. The proposed deep electron traps are relevant for all organic electronics applications in which non-covalently linked fullerenes in van der Waals contact with one another serve as n-type semiconductors.

No abstract