A New Effective Method for the Synthesis of 1,2,4-Triazole-3-carboxamide and Ribavirin Derivatives

Synthetic 1,2,4-triazole-3-carboxamides Induce Cell Cycle Arrest and Apoptosis in Leukemia Cells

BACKGROUND

A number of studies demonstrate the efficacy of ribavirin against various cancer types in in vitro and in vivo models. However, ribavirin induces the development of multiple side effects, suggesting a high demand for ribavirin analogues with improved therapeutic indexes.

OBJECTIVE

This study was focused on the analysis of ribavirin, its aglycon 1,2,4-triazole-3-carboxamide, and several of its derivatives activities in blood cancer cells in vitro.

METHODS

Four 1,2,4-triazole-3-carboxamide derivatives were designed and synthesized. Antiproliferative effects were evaluated in chronic myeloid leukemia cells К562 and acute lymphoblastic leukemia cells CCRF-SB as well as in the cells of whole blood mononuclear fraction of healthy volunteers by cell counting using the trypan blue exclusion method. Cell cycle distribution and apoptosis under the influence of the compounds were analyzed by flow cytometry with PI staining, and then apoptosis data were confirmed by Western blot analysis for PARP1 and caspase-3 cleavage.

RESULTS

We demonstrated the significant antiproliferative effect of 5-(tetrahydropyran-2-yl)-1,2,4-triazole-3- carboxamide and 1-(tetrahydropyran-2-yl)-1,2,4-triazol-3-carboxamide in leukemia cell lines in vitro in comparison to non-transformed monocytes, providing the rationale for further studies of 1,2,4-triazole-3-carboxamide derivatives as anti-leukemia drugs.

CONCLUSION

These results implied that the 1,2,4-triazole-3-carboxamide derivatives exhibited their antiproliferative activities by induction of cell cycle arrest. Consequently, 5-(tetrahydropyran-2-yl)-1,2,4-triazole-3-carboxamide and 1-(tetrahydrofuran-2-yl)-1,2,4-triazol-3-carboxamide may present antimetabolites with potential anticancer efficacy.

Thermodynamic modelling of solubility and preferential solvation for ribavirin (II) in co-solvent mixtures of (methanol, n-propanol, acetonitrile or 1,4-dioxane) + water

The equilibrium solubility of ribavirin in solvent mixtures of {methanol (1) + water (2)}, {n-propanol (1) + water (2)}, {acetonitrile (1) + water (2)} and {1,4-dioxane (1) + water (2)} was determined experimentally by using isothermal dissolution equilibrium method within the temperature range from (278.15 to 318.15) K under atmospheric pressure (101.1 kPa). At the same temperature and mass fraction of methanol (n-propanol, acetonitrile or 1,4-dioxane), the mole fraction solubility of ribavirin is greater in (methanol + water) than in the other three solvent mixtures. The preferential solvation parameters were derived from their thermodynamic solution properties by means of the inverse Kirkwood-Buff integrals. The preferential solvation parameters for methanol, n-propanol, acetonitrile or 1,4-dioxane (δx _1,3) were negative in the four solvent mixtures with a very wide compositions, which indicated that ribavirin was preferentially solvated by water. Temperature had little effect on the preferential solvation magnitudes. The higher solvation by water could be explained in terms of the higher acidic behaviour of water interacting with the Lewis basic groups of the ribavirin. Besides, the solubility of the drugs was mathematically represented by using the Jouyban-Acree model, van't Hoff-Jouyban-Acree model and Apelblat-Jouyban-Acree model obtaining average relative deviations lower than 1.57% for correlative studies. It is noteworthy that the solubility data presented in this work contribute to expansion of the physicochemical information about the solubility of drugs in binary solvent mixtures and also allows the thermodynamic analysis of the respective dissolution and specific solvation process.

An Efficient Chemoenzymatic Process for Preparation of Ribavirin

Ribavirin is an important antiviral drug, which is used for treatment of many diseases. The pilot-scale chemoenzymatic process for synthesis of the active pharmaceutical ingredient Ribavirin was developed with 32% overall yield and more than 99.5% purity. The described method includes the chemical synthesis of 1,2,4-triazole-3-carboxamide, which is a key intermediate and enzyme-catalyzed transglycosylation reaction for preparation of the desired product. 1,2,4-Triazole-3-carboxamide was synthesized from 5-amino-1,2,4-triazole-3-carboxylic acid by classical Chipen-Grinshtein method. Isolated fromE. сoliBL21(DE3)/pERPUPHHO1 strain the purine nucleoside phosphorylase was used as a biocatalytical system. All steps of this process were optimized and scaled.