Multicomponent synthesis of 4,4-dimethyl sterol analogues and their effect on eukaryotic cells.

Most sterols, such as cholesterol and ergosterol, become functional only after the removal of the two methyl groups at C-4 from their biosynthetic precursors. Nevertheless, some findings suggest that 4,4-dimethyl sterols might be involved in specific physiological processes. In this paper we present the synthesis of a collection of analogues of 4,4-dimethyl sterols with a diamide side chain and a preliminary analysis of their in vitro activity on selected biological systems. The key step for the synthesis involves an Ugi condensation, a versatile multicomponent reaction. Some of the new compounds showed antifungal and cytotoxic activity.

Synthesis and biological evaluation of 2-alkylaminoethyl-1,1-bisphosphonic acids against Trypanosoma cruzi and Toxoplasma gondii targeting farnesyl diphosphate synthase.

The effect of a series of 2-alkylaminoethyl-1,1-bisphosphonic acids against proliferation of the clinically more relevant form of Trypanosoma cruzi, the etiologic agent of American trypanosomiasis (Chagas' disease), and against tachyzoites of Toxoplasma gondii has been studied. Most of these drugs exhibited an extremely potent inhibitory action against the intracellular form of T. cruzi, exhibiting IC(50) values at the low micromolar level. This cellular activity was associated with a strong inhibition of the enzymatic activity of T. cruzi farnesyl diphosphate synthase (TcFPPS), which constitutes a valid target for Chagas' disease chemotherapy. Compound 17 was an effective agent against amastigotes exhibiting an IC(50) value of 0.84 microM, while this compound showed an IC(50) value of 0.49 microM against the target enzyme TcFPPS. Interestingly, compound 19 was very effective against both T. cruzi and T. gondii exhibiting IC(50) values of 4.1 microM and 2.6 microM, respectively. In this case, 19 inhibited at least two different enzymes of T. cruzi (TcFPPS and solanesyl diphosphate synthase (TcSPPS); 1.01 microM and 0.25 microM, respectively), while it inhibited TgFPPS in T. gondii. In general, this family of drugs was less effective against the activity of T. cruzi SPPS and against T. gondii growth in vitro. As bisphosphonate-containing compounds are FDA-approved drugs for the treatment of bone resorption disorders, their potential low toxicity makes them good candidates to control tropical diseases.