Heterocyclization of functionalized vinylic derivatives of imidazo.

Heterocyclization of functionalized vinylic derivatives of imidazo[1,2-a]pyridines was explored experimentally and theoretically using semiempirical AM1 and ab initio methods. A range of functionalized vinylic derivatives (azido, amino, and carbodiimide groups) were prepared for conversion into pyrroloazaindoles 19-22, imidazo[1,x]-, (x = 5, 6, 7, 8), [2,6]-, and [2,7]naphthyridines 28-30, 35-38 by thermal reaction. In the case of vinylic groups in the 5 position, peri annulation also was observed. The experimental and theoretical data are compared and discussed.

Synthesis and in vitro cytotoxic evaluation of new derivatives of pyrido[1,2-a]benzimidazolic ring system: the pyrido[1',2':1,2]imidazo[4,5-h]quinazolines.

Access to the original series of pyrido[1',2':1,2]imidazo[4,5-h]quinazoline was developed from a 1,3-dicarbonyl unit with some "N-C-N" bisnucleophilic reagents and the derivatives obtained were evaluated for in vitro cytotoxic activities against HL60 and A2780 cells. All compounds exhibited cytotoxic activities on resistant cell lines (MDR+; HL60R and A2780R) with no resistance phenomena.

Synthesis of 3-nitrosoimidazo[1,2-a]pyridine derivatives as potential antiretroviral agents.

Ten 2-aryl or heteroaryl-3-nitrosoimidazo[1,2-a]pyridine derivatives were synthesised as potential antiretroviral agents. The new compounds were characterized by elemental analysis, 1H NMR, and by crystallography for (14). The compounds were devoid of any activity against HIV-1 or HIV-2.

3-Benzamido, ureido and thioureidoimidazo[1,2-a]pyridine derivatives as potential antiviral agents.

This work reports the synthesis and the antiviral activities of 3-benzamido, 3-phenylureido and 3-phenylthioureido derivatives in the imidazo[1,2-a]pyridine series. The structure was proven by NMR spectroscopy. The synthesized compounds were evaluated against a large number of viruses. The 3-phenylthioureido derivative 7 showed moderate activity against human cytomegalovirus (HCMV) in vitro. The crystallographic data for 8 are also reported and explain the absence of activity against human immunodeficiency virus (HIV).

New potential antimalarial agents: synthesis and biological activities of original diaza-analogs of phenanthrene.

Several diaza-analogs of phenanthrene derived from 3-amino, 5-amino, 6-amino, 8-aminoquinolines, and 5-aminoisoquinoline were prepared to evaluate their antiplasmodial activities. All compounds showed mild to good activitiy in vitro, both on a Nigerian chloroquino-sensitive strain and on the chloroquino-resistant FcB1-Columbia and FcM29 strains. The position of the intracyclic nitrogen atom is shown to be crucial for the activities (best results are obtained with a 1,10-phenanthroline skeleton). In regard to the particular properties of this structure (metalloprotease inhibition activitiy by chelating divalent metal ions), the potential chelating site of the molecule was blocked. In this case, the biological activity of the compound was greatly enhanced, showing that the mechanism of action of such a compound is probably not correlated to metalloprotease inhibition activity.

Synthesis of imidazo[1,2-a]pyridines as antiviral agents.

The synthesis of original imidazo[1,2-a]pyridines bearing a thioether side chain at the 3 position and their antiviral activity are reported. From the synthesized compounds, 4, 15, and 21 were highly active against human cytomegalovirus with a therapeutic index superior to 150. These compounds also showed pronounced activity against varicella-zoster virus. Their structure-activity relationship is discussed.

Regioselective synthesis of pyrazolo[4,5-g]pyrido[1,2-a]benzimidazoles: cytotoxic derivatives of pyrido[1,2-a]benzimidazolic ring system.

N-1 and N-2 substituted pyrazolo[4,5-g]pyrido[1,2-a]benzimidazoles were prepared regioselectively, and cytotoxicities evaluated in vitro against K562 and HL60 cells. All compounds displayed weaker activity than doxorubicin against sensitive lines, but showed the same activity against resistant cell lines (multidrug resistance+, (MDR+); K562R and HL60R) indicating no resistance phenomena.

Synthesis of acyclo-C-nucleosides in the imidazo[1,2-a]pyridine and pyrimidine series as antiviral agents.

The synthesis and the antiviral activities of C-3 acyclic nucleoside analogues of imidazo[1,2-a]pyridine and pyrimidine are reported. From these compounds, 20, 21, 22, 23, 28, and 34 showed a specific activity against cytomegalovirus and/or varicella-zoster virus.