Enzymatic Synthesis of Austroeupatol Esters with Enhanced Antiprotozoal Activity.

Austroeupatol, the principal diterpene isolated from the invasive shrub , holds promise for structural diversification and biological assessment of its derivatives due to its abundant availability and high yield isolation. We propose an efficient enzymatic synthesis of a series of austroeupatol esters derived from aliphatic and heterocyclic carboxylic acids. Systematic optimization of reaction parameters, including enzyme type and quantity, acylating agent amount, solvent, and temperature, was conducted.

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.

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.

New Insights into the Chemistry of Lithium Carbamoyls: Characterization of an Adduct (R(2)NC(O)CLi(OLi)NR(2)).

Studies of the reaction of lithium dicyclohexylamide with N,N-dibutylformamide, 1-formylpiperidine, and 4-formylmorpholine indicate that the equilibria resulting from these compounds are shifted toward the formation of an adduct, which quickly collapses to dicyclohexylamine and the lithiated carbamoyl anion derived from the initial disubstituted formamide. Further reactions of the lithium carbamoyl lead to a new adduct where a lithiated carbon is bounded to N, O, and a carbonyl functionality. The (13)C NMR analysis of the reaction mixtures showed the presence of similar intermediates in all cases: adducts of this type have not been reported before.