Thiosulfuric acid analog of quinine as a potential antimalarial agent

Stereoselective Domino Rearrangement peri-Annulation of Cinchona Alkaloid Derivatives with 8-Bromo-1-naphthyl Grignard

The unexpected domino coupling and rearrangement of the Cinchona alkaloid skeleton has been found to occur in the reaction of 9-chloro-9-deoxy-alkaloids with Grignards from peri-dihalogenonaphthalene. The cyclization and migration of the central quinuclidinylmethyl group (C9) from position C-4′ to position C-3′ of quinoline formed a novel chiral ring system of 5-aza-7H-benzo[no]tetraphene, yielding products of unlike configuration. The proposed reaction pathway involves radical intermediates.

Determination of picomolar concentrations of thiol compounds in natural waters and biological samples by tandem mass spectrometry with online preconcentration and isotope-labeling derivatization

We present a sensitive, selective and robust method for the determination of 14 thiol compounds in aqueous samples. Thiols were derivatized with ω-bromoacetonylquinolinium bromide (BQB) and its deuterium labeled equivalent D7-ω-bromoacetonylquinolinium bromide (D7). Derivatized thiols were preconcentrated by online solid-phase extraction (SPE) followed by liquid chromatography separation and electrospray ionization tandem mass spectrometry determination (SPE/LC-ESI-MS/MS). The robustness of the method was validated for wide ranges in pH, salinity, and concentrations of sulfide and dissolved organic carbon (DOC) to cover contrasting natural water types. The limits of detection (LODs) for the thiols were 3.1-66 pM. Between 6 and 14 of the thiols were detected in different natural sample types at variable concentrations: boreal wetland porewater (0.7-51 nM), estuarine sediment porewater (50 pM-11 nM), coastal sea water (60 pM-16 nM), and sulfate reducing bacterium cultures (80 pM-4 nM). MS/MS fragmentation of the compounds produces two pairs of common product ions, m/z 130.2/137.1 and 218.1/225.1, which enables scanning for unknown thiols in precursor ion scan mode. Using this approach, we identified cysteine, mercaptoacetic acid, N-acetyl-L-cysteine and sulfurothioic S-acid in boreal wetland porewater. The performance of the developed method sets a new state of the art for the determination of thiol compounds in environmental and biological samples.

Synthesis and antimalarial activity of heterocyclic alkyl disulfides, thiosulfates, and dithio acid derivatives

Based on the antimalarial activity in mice of bis(4-rho-acetamidobenzenesulfonamidophenyl) disulfide, a series of N-heterocyclic alkyl disulfides and thiosulfates was synthesized and screened for antimalarial activity. Several related dithio acid dianions and S- blocked derivatives were also screened to provide an indication of the possible role that thiol anions might play in malaria chemotherapy. Activity was limited by toxicity with these compounds, and none of those tested, with the exception of bis(4-rho-acetamidobenzenesulfonamidophenyl) disulfide, showed curative activity in either a mouse or chick test.