Lipase-Catalyzed Synthesis and Biological Evaluation of N-Picolineamides as Trypanosoma cruzi Antiproliferative Agents.

pubs.acs.org/acsmedchemlett Letter Lipase-Catalyzed Synthesis and Biological Evaluation of N‑Picolineamides as Trypanosoma cruzi Antiproliferative Agents Fabricio Freije García, Daniel Musikant, José L. Escalona, Martín M. Edreira, and Guadalupe García Liñares* Cite This: ACS Med. Chem. Lett. 2023, 14, 59−65 ACCESS Metrics & More Read Online Article Recommendations sı Supporting Information * ABSTRACT: In our search for new safe antiparasitic agents, an enzymatic pathway was applied to synthesize a series of Npyridinylmethyl amides derived from structurally different carboxylic acids. Thirty derivatives, including 11 new compounds, were prepared through lipase-catalyzed acylation in excellent yields. In order to optimize the synthetic methodology, the impact of different reaction parameters was analyzed. Some compounds were evaluated as antiproliferative agents against Trypanosoma cruzi, the parasite responsible for American trypanosomiasis (Chagas’ disease). Some of them showed significant activity as parasite proliferation inhibitors. Amides derived from 2-aminopicoline and stearic and elaidic acids were as potent as nifurtimox against the amastigote form of T. cruzi, the clinically relevant form of the parasite. Even more, a powerful synergism between nifurtimox and N-(pyridin-2-ylmethyl)stereamide was observed, almost completely inhibiting the proliferation of the parasite. Besides, the obtained compounds showed no toxicity in Vero cells, making them excellent potential candidates as lead drugs. KEYWORDS: picoline derivatives, Chagas’ disease, lipase, enzymatic synthesis nfections provoked by trypanosomatids are among the most prevalent parasitic diseases worldwide.1 In particular, Chagas disease, a life-threatening disease caused by Trypanosoma cruzi, represents a serious threat to the health of people living in poor populations in Latin America, where it is estimated that around 8 million people are infected and over 40 million individuals are at risk of infection.2,3 In developed countries, where Chagas’ disease is not endemic, the main transmission mechanism is via the placenta, migration of individuals, or by blood transfusion.4,5 Recently, it has been demonstrated that Chagas disease can be also transmitted sexually6 or by food ingestion.7 The current chemotherapy for Chagas’ disease is still deficient and is limited to two old and empirically discovered drugs, nifurtimox (1) and benznidazole (2) (Chart 1), that show unwanted and severe side effects, especially when used in the chronic phase of the disease.4,8−10 Even though in the last 50 years some compounds, mostly antifungals, have been I studied in clinical trials without success,11−13 no new drugs have been developed to replace the current therapy. Therefore, there is an urgent need for the development of a safe and effective chemotherapy involving new antiparasitic drugs.14,15 It is widely known that numerous compounds that contain an aromatic nitrogen heterocyclic ring are among the most significant structural components of approved pharmaceuticals.16 Particularly, pyridines,17 pyrimidines,18,19 and quinolines20−23 are interesting scaffolds for the development of new drugs. Specifically, pyridine, a simple six-membered heterocycle containing one nitrogen atom in the ring, is found in a variety of naturally occurring compounds and pharmaceutical compounds.24 Pyridine derivatives have been reported for a variety of biological properties, such as anticancer activity,25,26 antimicrobial activity,27 and antiviral activity.28 However, little has been reported about new compounds showing activity against T. cruzi. Chart 1. Chemical Structure of Current Drugs Clinically Employed for the Treatment of Chagas’ Disease Received: September 20, 2022 Accepted: December 28, 2022 Published: January 3, 2023 © 2023 American Chemical Society 59 https://doi.org/10.1021/acsmedchemlett.2c00425 ACS Med. Chem. Lett. 2023, 14, 59−65 ACS Medicinal Chemistry Letters pubs.acs.org/acsmedchemlett Enzymes are interesting catalysts, which provide highly sustainable alternatives to conventional chemical methods,29−32 arising in the last years as efficient catalysts for synthesis under mild reaction conditions for a great scope of reactions, with high selectivity and large substrate specificity.33−35 Hydrolases constitute a class of enzymes, which catalyze either hydrolytic or reverse bond-formation reactions. Due to their easy handling to not needing a cofactor and their ability to perform in aqueous systems and in organic solvents, hydrolases have been incorporated into numerous synthetic routes, allowing the efficient production of alcohols, amines, esters, amides, epoxides, and nitriles, among other relevant molecules.36−39 This class of enzymes has been also industrially applied to the synthesis of, for example, pharmaceuticals, agrochemicals, and several high added-value substances.29,40,41 In the last years, lipases have been extensively used in nonaqueous media for a variety of organic transformations such as aminolysis, esterifications, polymerizations, etc.33,34,42−45 Using lipases, we have obtained diverse biologically active novel compounds from multiple substrates, with applications as potential antiparasitic,23,46,47 antitumoral,48 and antiviral agents.49,50 In this work, an enzymatic synthesis of N-pyridinylmethyl amides derived from structurally different carboxylic acids was performed to obtain a set of new compounds containing a pyridine ring (Chart 2). In recent years, much attention has been focused on this type of compound because many of them have interesting activities. In our ongoing research in the field of antiparasitic activity of organic compounds, we have also tested the title compounds as potential growth inhibitors of the protozoan T. cruzi. Letter Scheme 1. Preparation of 2-, 3-, and 4-Pyridinylmethyl Amino Derivatives In the first place, a good combination of lipase and solvent, using 4-(aminomethyl)pyridine (4-AMP, 5) and ethyl acetate as acyl donor, was pursued. The conditions used for this step of the optimization were known to perform well in other amide syntheses: 30 °C, 200 rpm stirring, a 5.0 enzyme/substrate ratio (E/S, m/m), 5.0 acylating agent/substrate ratio (A/S, mol/mol), and a substrate concentration of 9.25 mM.49 The lipases tested were lipozyme from Rhizomucor miehei (RMIM), Lipase B from Candida antarctica (CAL B), and lipozyme from Thermomyces lanuginosus (TLIM). On account of the effect of solvents in lipase-catalyzed reactions being dependent on the type of substrate, it is difficult to predict.55 Therefore, to select a suitable solvent, screening experiments were carried out. nHexane, toluene, and diisopropyl ether (DIPE) were initially tested. As can be seen in Table 1, the three enzymes were active, and CAL B and TLIM were the ones that gave the most satisfactory results. The conversion percentage was determined at 72 h of reaction. The n-hexane, despite be (...truncated)