A Photochemical Approach to Pyridopyrroloquinoline Derivatives as New Potential Anticancer Agents

Direct conversion of phenols into primary anilines with hydrazine catalyzed by palladium

Primary anilines are essential building blocks to synthesize various pharmaceuticals, agrochemicals, pigments, electronic materials, and others. To date, the syntheses of primary anilines mostly rely on the reduction of nitroarenes or the transition-metal-catalyzed Ullmann, Buchwald-Hartwig and Chan-Lam cross-coupling reactions with ammonia, in which non-renewable petroleum-based chemicals are typically used as feedstocks via multiple step syntheses. A long-standing scientific challenge is to synthesize various primary anilines directly from renewable sources. Herein, we report a general method to directly convert a broad range of phenols into the corresponding primary anilines with the cheap and widely available hydrazine as both amine and hydride sources with simple Pd/C as the catalyst.

Aplidiopsamine A, an antiplasmodial alkaloid from the temperate Australian ascidian, Aplidiopsis confluata

A polyaromatic alkaloid, aplidiopsamine A was isolated from the temperate Australian ascidian, Aplidiopsis confluata, and its structure was determined from interpretation of mass, 1D and 2D NMR spectra. Aplidiopsamine A is the first alkaloid to possess the tricyclic aromatic substructure 3H-pyrrolo[2,3-c]quinoline conjugated to an adenine. Aplidiopsamine A exhibited significant inhibition of growth of chloroquine resistant and sensitive strains of the malaria parasite, Plasmodium falciparum, and minimal toxicity toward human cells.

Identification of benzofuro[2,3-b]quinoline derivatives as a new class of antituberculosis agents

A series of 11-alkoxylated and 11-aminated benzofuro[2,3-b]quinoline derivatives were designed, synthesized, and evaluated for their anti-TB and cytotoxic activities. The known 11-chlorobenzofuro[2,3-b]quinoline (3) was synthesized in a single step from anthranilic acid and 2-coumaranone in phosphorus oxychloride in 51% yield for the first time. Treatment of 3 with alcohols and amines gave 11-alkoxylated and 11-aminated benzofuro[2,3-b]quinoline derivatives respectively, which were evaluated for their anti-TB and cytotoxic activities. Our results indicated that 11-arylaminated derivatives were more active than their respective 11-aryloxylated isosteric isomers against Mycobacterium tuberculosis. Among the tested compounds, 11-methoxybenzofuro[2,3-b]quinoline (4), 11-methylamino- benzofuro[2,3-b]quinoline (9), and 11-dimethylaminobenzofuro[2,3-b]quinoline (14) exhibited significant activities against the growth of M. tuberculosis (MIC values of <0.20 microg/mL) and low cytotoxicities against VERO cell with IC(50) values of 11.77, 5.55, and >30.00 microg/mL respectively. The selectivity index (SI=IC(50)/MIC) for 4, 9, and 14 was greater than 58.85, 27.75, and 150 respectively.

Liposomal formulation of DIMIQ, potential antitumor indolo[2,3-b]quinoline agent and its cytotoxicity on hepatoma Morris 5123 cells

The cytotoxic and antitumor activity of DIMIQ (5,11-dimethyl-5H-indolo[2,3-b]quinoline), synthetic analog of neocryptolepine, makes this compound a potential antitumor agent. An attempt to obtain liposomal form of DIMIQ.HCl was undertaken in the present study. Standard experimental conditions were chosen and information on the physicochemical parameters of the liposome dispersion containing studied indoloquinoline agent was collected. The effective and efficient encapsulation of DIMIQ.HCl (66.6%) in conventional liposomes (FAT-MLV, DMPC:DMPG 7:3 w/w at pH 7.0), uniformity of the size of liposomal vesicles, and high stability at pH 6.5 were demonstrated. Hemolysis of sheep erythrocytes induced by free form of DIMIQ.HCl was dramatically decreased after addition of liposome-entrapped DIMIQ.HCl. Treatment of hepatoma Morris 5123 cells for 24 hr with different concentrations of both free and its liposomal formulation of DIMIQ.HCl resulted in significant changes in cell morphology accompanied by reduction of cell viability.

Synthesis and Biological Evaluation of Indoloquinolines and Pyridocarbazoles: A New Example of Unexpected Photoreduction Accompanying Photocyclization

Indoloquinoline alkaloid cryptolepine and pyridocarbazole alkaloid ellipticine are of great interest because in vitro and in vivo studies revealed their good cytotoxic properties. In order to obtain some biologically active analogs of these compounds, we developed a synthesis based on the photocyclization of tertiary N-substituted enaminones derived from 1,3-cyclohexandione and 3 or 6-aminoquinoline. The angular cyclized compounds thus obtained were tested in vitro on K 562 cells and A 2780 doxorubicin sensitive and resistant cells. All compounds were less effective than doxorubicin in sensitive cells but their activity wasn't decreased by MDR resistance.

InVitro and inVivo Antimalarial Activity of Derivatives of 1,10-Phenanthroline Framework

A series of trisubstituted 1,10-phenanthrolines was prepared. These compounds exhibited mild to high biological activities in vitro both toward chloroquino-resistant FcB1-Columbia and FcM29-Cameron strains and Nigerian chloroquino-sensitive strain of Plasmodium falciparum. Cytotoxicity of the most active compounds was estimated showing that one compound (10) exhibited a selective activity against malaria parasite (selectivity indexes of 52 and 144). Antiplasmodial activity of this derivative was optimized by N-10 alkylation and the phenanthrolinium salt (15) submitted to an in vivo study using mice infected by P. vinckei petteri showing an ED50 of 7.86 mg/kg/day.