Easy Access to 3- or 5-Heteroarylamino-1,2,4-triazines by SNAr, SNH, and Palladium-Catalyzed N-Heteroarylations

SNH Amidation of 5-Nitroisoquinoline: Access to Nitro- and Nitroso Derivatives of Amides and Ureas on the Basis of Isoquinoline

For the first time, amides and ureas based on both 5-nitroisoquinoline and 5-nitrosoisoquinoline were obtained by direct nucleophilic substitution of hydrogen in the 5-nitroisoquinoline molecule. In the case of urea and monosubstituted ureas, only 5-nitrosoisoquinoline-6-amine is formed under anhydrous conditions.

Synthetic accesses to biguanide compounds

Biguanide is a unique chemical function, which has attracted much attention a century ago and is showing resurgent interest in recent years after a long period of dormancy. This class of compounds has found broad applications such as reaction catalysts, organic strong bases, ligands for metal complexation, or versatile starting materials in organic synthesis for the preparation of nitrogen-containing heterocycles. Moreover, biguanides demonstrate a wide range of biological activities and some representatives are worldwide known such as metformin, the first-line treatment against type II diabetes, or chlorhexidine, the gold standard disinfectant and antiseptic. Although scarcely represented, the number of "success stories" with biguanide-containing compounds highlights their value and their unexploited potential as future drugs in various therapeutic fields or as efficient metal ligands. This review provides an extensive and critical overview of the synthetic accesses to biguanide compounds, as well as their comparative advantages and limitations. It also underlines the need of developing new synthetic methodologies to reach a wider variety of biguanides and to overcome the underrepresentation of these compounds.

Solvent-free synthesis of 5-(aryl/alkyl)amino-1,2,4-triazines and α-arylamino-2,2′-bipyridines with greener prospects

A convenient approach towards 5-(aryl/alkyl)amino-1,2,4-triazines and α-arylamino-2,2′-bipyridines was developed following ipso-substitution of a cyano-group by amino groups and, finally, aza-Diels-Alder reaction with 1-morpholynocyclopentene.

A new synthetic approach to the imidazo[1,5-a]imidazole-2-one scaffold and effective functionalization through Suzuki–Miyaura cross coupling reactions

A pathway to new 7-bromo-1-(4-methoxybenzyl)-5-methyl-imidazo[1,5-a]imidazole-2-one was reported. The synthetic potential of this scaffold was demonstrated by displacing bromine by Suzuki–Miyaura cross-coupling reactions.

Amination of nitroazoles--a comparative study of structural and energetic properties

In this work, 3-nitro-1H-1,2,4-triazole (1) and 3,5-dinitro-1H-pyrazole (2) were C-aminated and N-aminated using different amination agents, yielding their respective C-amino and N-amino products. All compounds were fully characterized by NMR (¹H, ¹³C, ¹⁵N), IR spectroscopy, differential scanning calorimetry (DSC). X-ray crystallographic measurements were performed and delivered insight into structural characteristics as well as inter- and intramolecular interactions of the products. Their impact sensitivities were measured by using standard BAM fallhammer techniques and their explosive performances were computed using the EXPLO 5.05 program. A comparative study on the influence of those different amino substituents on the structural and energetic properties (such as density, stability, heat of formation, detonation performance) is presented. The results showed that the incorporation of an N-amino group into a nitroazole ring can improve nitrogen content, heat of formation and impact sensitivity, while the introduction of a C-amino group can enhance density, detonation velocity and pressure. The potential of N-amino and C-amino moieties for the design of next generation energetic materials is explored.

Introduction of polar groups on the naphthalene scaffold of molecular tongs inhibiting wild-type and mutated HIV-1 protease dimerization

A new series of naphthalene-based molecular tongs containing polar groups at the 3-position of the naphthalene scaffold was synthesized and its anti-dimerization activity was evaluated against HIV-1 protease.

Combinatorial solid-phase synthesis of 4,6-diaryl and 4-aryl, 6-alkyl-1,3,5-triazines and their application to efficient biofuel production

Herein we report the solid-phase synthesis of a combinatorial aryl, alkyl-triazine library and its application to biofuel production. The combination of Grignard reactions and solid supported Suzuki coupling reactions afforded unique 120 triazine compounds with high purities and minimum purification steps. Through an unbiased phenotypic screening for improved biofuel generation in oleaginous yeast, we found one diaryl triazine derivative (E4) which increased the biolipid production up to 86%.

New ferrocenic pyrrolo[1,2-a]quinoxaline derivatives: synthesis, and in vitro antimalarial activity

Following our search for antimalarial compounds, novel series of ferrocenic pyrrolo[1,2-a]quinoxaline derivatives 1-2 were synthesized from various substituted nitroanilines and tested for in vitro activity upon the erythrocytic development of Plasmodiumfalciparum strains with different chloroquine-resistance status. The pyrrolo[1,2-a]quinoxalines 1 were prepared in 6-8 steps through a regioselective palladium-catalyzed monoamination by coupling 4-chloropyrrolo[1,2-a]quinoxalines with 1,3-bis(aminopropyl)piperazine or -methylamine using Xantphos as the ligand. The ferrocenic bispyrrolo[1,2-a]quinoxalines 2 were prepared by reductive amination of previously described bispyrrolo[1,2-a]quinoxalines 9 with ferrocene-carboxaldehyde, by treatment with NaHB(OAc)(3). The best results were observed with ferrocenic pyrrolo[1,2-a]quinoxalines linked by a bis(3-aminopropyl)piperazine. Moreover, it was observed that a methoxy group on the pyrrolo[1,2-a]quinoxaline nucleus and no substitution on the terminal N-ferrocenylmethylamine function enhanced the pharmacological activity. Selected compounds 1b, 1f-h, 1l and 2a were tested for their ability to inhibit beta-haematin formation, the synthetic equivalent of hemozoin, by using the HPIA (heme polymerization inhibitory activity) assay. Of the tested compounds, only 2a showed a beta-haematin formation inhibition, but no inhibition of haem polymerization was observed with the other selected ferrocenic monopyrrolo[1,2-a]quinoxaline derivatives 1b, 1f-h and 1l, as the IC(50) values were superior to 10 equivalents.

Synthesis and biological evaluation of 7-azaindole derivatives, synthetic cytokinin analogues

Cytokinins, N6-substituted adenine derivatives, are plant hormones playing important roles in various processes in plant development. Furthermore, cytokinins and their derivatives are able to control mammalian cell apoptosis and differentiation. The aim of our study was the synthesis of 7-azaindole derivatives as cytokinin analogues with the Hartwig-Buchwald coupling reaction in order to evaluate their biological properties on human myeloblastic leukaemia cells (HL-60 cell line). All these compounds presented a cytotoxic activity on HL-60 cells especially the 4-phenylaminopyrrolo[2,3-b]pyridine and the 4-phenethylaminopyrrolo[2,3-b]pyridine.