Medicinal Chemistry for Sustainable Development.

Pharmaceutical chemistry has many industrial processes that must be studied and adapted to a new reality where the environment must be the focus of all production chains. Thus, new technologies that are cleaner and use renewable sources of raw materials still need to be developed and applied to materials that go to the market, and they need to reach a level that is less harmful to the environment. This applies especially in areas related to the pharmaceutical industries since chemical products are used in the production of medicines and used in many other areas of everyday life and are included in the Sustainable Development Goals proposed by the United Nations. This article intends to provide insight into some relevant topics that can stimulate researchers toward medicinal chemistry that can contribute to a sustainable future of the biosphere. This article is structured around four interconnected themes that influence how green chemistry can be important for a future where science, technology and innovation are key to mitigating climate change and increasing global sustainability.

An Update on the Synthesis and Applications of Bis(Naphthoquinones): An Important Class of Molecules against Infectious Diseases and other Conditions.

Naphthoquinones are important molecules belonging to the general class of quinones, and many of these compounds have become drugs that are in the pharmaceutical market for the treatment of several diseases. A special subclass of compounds is that of the bis(naphthoquinones), which have two linked naphthoquinone units. In the last few years, several synthetic approaches toward such valuable compounds have been described, as well as their evaluation against numerous important biological targets. In this review, we provide a thorough discussion on the various synthetic methods reported for the synthesis of bis(naphthoquinone) analogues, also highlighting the biological activities of these substances.

Bioactive 1,2,3-Triazoles: An Account on their Synthesis, Structural Diversity and Biological Applications.

The triazole heterocycle is a privileged scaffold in medicinal chemistry, since its structure is present in a large number of biologically active molecules, including several drugs currently in the market. Due to their vast applications, a wide variety of methods are described for their preparation, such as the 1,3-dipolar cycloaddition and processes involving diazo compounds and diazo transfer reactions. Considering the significant number of contributions from our research group to this chemistry in recent decades, in this account we discuss both the development of new methods for the synthesis of 1,2,3-triazoles and the preparation of new triazole-functionalized biologically active molecules using classical approaches.

Quinone-Based Drugs: An Important Class of Molecules in Medicinal Chemistry.

BACKGROUND: Several quinones are on the pharmaceutical market as drugs for the treatment of several diseases. OBJECTIVE: The aim of this review was to provide an overview of the quinones that have become drugs for several therapeutic applications. METHODS: We have comprehensively and critically discussed all the information available in the literature about quinone-based drugs. RESULTS: In this review, the various aspects of the chemistry and biochemistry of these drugs are highlighted, including their repositioning, drug combination and their new uses. CONCLUSION: A number of studies related to quinone drugs for different pharmaceutical uses show that the interest in new applications is still increasing in recent years.

Efficient Synthesis and Antibacterial Profile of Bis(2-hydroxynaphthalene- 1,4-dione).

BACKGROUND: Antibacterial resistance is a serious public health problem infecting millions in the global population. Currently, there are few antimicrobials on the market against resistant bacterial infections. Therefore, there is an urgent need for new therapeutic options against these strains. OBJECTIVE: In this study, we synthesized and evaluated ten Bis(2-hydroxynaphthalene-1,4-dione) against Gram-positive strains, including a hospital Methicillin-resistant (MRSA), and Gram-negative strains. METHODS: The compounds were prepared by condensation of aldehydes and lawsone in the presence of different L-aminoacids as catalysts in very good yields. The compounds were submitted to antibacterial analysis through disk diffusion and Minimal Inhibitory Concentration (MIC) assays. RESULTS: L-aminoacids have been shown to be efficient catalysts in the preparation of Bis(2- hydroxynaphthalene-1,4-dione) from 2-hydroxy-1,4-naphthoquinones and arylaldehydes in excellent yields of up to 96%. The evaluation of the antibacterial profile against Gram-positive strains (Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, S. epidermidis ATCC 12228) also including a hospital Methicillin-resistant S. aureus (MRSA) and Gram-negative strains (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Klebsiella pneumoniae ATCC 4352), revealed that seven compounds showed antibacterial activity within the Clinical and Laboratory Standards Institute (CLSI) levels mainly against P. aeruginosa ATCC 27853 (MIC 8-128 µg/mL) and MRSA (MIC 32-128 µg/mL). In addition, the in vitro toxicity showed all derivatives with no hemolytic effects on healthy human erythrocytes. Furthermore, the derivatives showed satisfactory theoretical absorption, distribution, metabolism, excretion, toxicity (ADMET) parameters, and a similar profile to antibiotics currently in use. Finally, the in silico evaluation pointed to a structure-activity relationship related to lipophilicity for these compounds. This feature may help them in acting against Gram-negative strains, which present a rich lipid cell wall selective for several antibiotics. CONCLUSION: Our data showed the potential of this series for exploring new and more effective antibacterial activities in vivo against other resistant bacteria.

α- and ß-Lapachone Isomerization in Acidic Media: Insights from Experimental and Implicit/Explicit Solvation Approaches.

Combined experimental and mixed implicit/explicit solvation approaches were employed to gain insights into the origin of switchable regioselectivity of acid-catalyzed lapachol cyclization and α-/ß-lapachone isomerization. It was found that solvating species under distinct experimental conditions stabilized α- and ß-lapachone differently, thus altering the identity of the thermodynamic product. The energy profile for lapachol cyclization revealed that this process can occur with low free-energy barriers (lower than 8.0 kcal mol-1 ). For α/ß isomerization in a dilute medium, the computed enthalpic barriers are 15.1 kcal mol-1 (α→ß) and 14.2 kcal mol-1 (ß→α). These barriers are lowered in concentrated medium to 11.5 and 12.6 kcal mol-1 , respectively. Experimental determination of isomers ratio was quantified by HPLC and NMR measurements. These findings provide insights into the chemical behavior of lapachol and lapachone derivatives in more complex environments.

Design, Synthesis and Biological Evaluation of 1H-1,2,3-Triazole-Linked-1H-Dibenzo[b,h]xanthenes as Inductors of ROS-Mediated Apoptosis in the Breast Cancer Cell Line MCF-7.

BACKGROUND: Low molecular weight 1,2,3-triazoles and naphthoquinones are endowed with various types of biological activity, such as against cancer, HIV and bacteria. However, in some cases, the conjugation of these two nuclei considerably increases their biological activities. OBJECTIVE: In this work, we decided to study the synthesis and screening of bis-naphthoquinones and xanthenes tethered to 1,2,3-triazoles against cancer cell lines, specifically the human breast cancer cell line MCF-7. RESULTS: Starting from lawsone and aryl-1H-1,2,3-triazole-4-carbaldehydes (10a-h) several new 7- (1-aryl-1H-1,2,3-triazol-4-yl)-6H-dibenzo[b,h]xanthene-5,6,8,13(7H)-tetraones (12a-h) and 3,3'- ((1-aryl-1H-1,2,3-triazol-4-yl)methylene)bis(2-hydroxynaphthalene-1,4-diones) 11a-h were synthesized and evaluated for their cytotoxic activities using the human breast cancer cell line MCF-7 and the non-tumor cell line MCF10A as control. We performed test of cell viability, cell proliferation, intracellular ATP content and cell cytometry to determine reactive oxygen species (ROS) formation. CONCLUSIONS: Based on these results, we found that compound 12a promotes ROS production, interfering with energy metabolism, cell viability and proliferation, and thus promoting whole cell damage.

Design, Synthesis and Antileishmanial Activity of Naphthotriazolyl-4- Oxoquinolines.

BACKGROUND: Leishmaniasis is a neglected public health problem caused by several protozoanspecies of the genus Leishmania. The therapeutic arsenal for treating leishmaniasis is quite limited, raising concerns about the occurrence of resistant strains. Furthermore, most of these drugs were developed more than 70 years ago and suffer from poor efficacy and safety and are not well adapted to the needs of patients. Therefore, research on novel natural or synthetic compounds with antiparasitic activity is urgently needed. In this paper, we evaluated the effect and the mechanism of action of naphthotriazolyl-4-oxoquinolines on promastigotes and intracellular amastigotes of Leishmania amazonensis. MATERIALS AND METHODS: The naphthotriazolyl-4-oxoquinoline derivatives were obtained in good to moderate yields via the [3+2] cycloaddition reaction between 1,4-naphtoquinone and azido-4- oxoquinoline derivatives. HMPA at 100°C was established as the best solvent and temperature condition for this reaction. The structures of the compounds were confirmed by spectral analyses (infrared spectroscopy, one- and two-dimensional ¹H and ¹³C NMR spectroscopy, and high-resolution mass spectrometry). The compounds exhibited promising activities with IC50 values ranging from 0.7 to 2.0 µM against intracellular amastigotes of Leishmania amazonensis. The most selective compound was the Npentyl- substituted derivative, which showed a Selectivity Index (SI) of 8.6, making it less toxic than pentamidine (SI 4.5). RESULTS: Our results demonstrated that all compounds, except the N-propyl-substituted derivative, induce ROS production by parasites early in the culture. As a proof of concept, we demonstrated that the most selective compound was able to interfere with sterol biosynthesis in L. amazonensis. CONCLUSION: The naphthotriazolyl-4-oxoquinoline derivatives were obtained in good to moderate yields. These conjugates have potent in vitro antileishmanial activity involving at least two different mechanisms of action, making them promising lead compounds for the development of new therapeutic alternatives for leishmaniasis.

A Novel Triazole Derivative Drug Presenting In Vitro and In Vivo Anticancer Properties.

BACKGROUND: Cancer is a major cause of death worldwide, despite many different drugs available to treat the disease. This high mortality rate is largely due to the complexity of the disease, which results from several genetic and epigenetic changes. Therefore, researchers are constantly searching for novel drugs that can target different and multiple aspects of cancer. EXPERIMENTAL: After a screening, we selected one novel molecule, out of ninety-four triazole derivatives, that strongly affects the viability and proliferation of the human breast cancer cell line MCF-7, with minimal effects on non-cancer cells. The drug, named DAN94, induced a dose-dependent decrease in MCF-7 cells viability, with an IC50 of 3.2 ± 0.2 µM. Additionally, DAN94 interfered with mitochondria metabolism promoting reactive oxygen species production, triggering apoptosis and arresting the cancer cells on G1/G0 phase of cell cycle, inhibiting cell proliferation. These effects are not observed when the drug was tested in the non-cancer cell line MCF10A. Using a mouse model with xenograft tumor implants, the drug preventing tumor growth presented no toxicity for the animal and without altering biochemical markers of hepatic function. RESULTS AND CONCLUSION: The novel drug DAN94 is selective for cancer cells, targeting the mitochondrial metabolism, which culminates in the cancer cell death. In the end, DAN94 has been shown to be a promising drug for controlling breast cancer with minimal undesirable effects.

Alternative Routes to the Click Method for the Synthesis of 1,2,3-Triazoles, an Important Heterocycle in Medicinal Chemistry.

Heterocyclic rings having nitrogen atoms are the molecular fragments most used in drug design by using the tools of medicinal chemistry. The 1,2,4-triazole rings are part of an extensive family of drugs that are in use in the pharmaceutical market. More recently, 1,2,3-triazole rings have begun to arouse the great interest of scientists and therefore, many researches have been developed seeking the synthesis of new substances and their possible biological activities. A number of articles have been published by us and others highlighting the synthetic and biological aspects of 1,2,3-triazoles. The growth of new substances of this class was largely due to the simple and selective synthetic method of 1,2,3- triazole ring developed by Sharpless et al. However, some 1,2,3-triazole cannot be synthesized by this method. This review focuses on other synthetic methods that give access to other variations around the 1,2,3-triazole core. The systematic arrangement in this review explores the possibility of providing practical guidance to alternatives of this heterocycle. It has been divided into sections according to the types of starting materials and reactions.

Synthesis and Biological Evaluation of Coumarins Derivatives as Potential Inhibitors of the Production of Pseudomonas aeruginosa Virulence Factor Pyocyanin.

Antimicrobial Resistance (AMR) is a serious problem for the humans since it threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, parasites, viruses and fungi. One way around this problem is to act on the virulence factors, produced by bacteria, which increase their infection effectiveness. In view of these facts, new coumarin derivatives were synthesized and evaluated for their anti-virulence biological activity towards Pseudomonas aeruginosa. The results suggest that coumarin derivatives with a secondary carbon at C-3 position reduces P. aeruginosa growth whereas compounds with one additional substituent have a significant effect over pyocyanin production (10k EC50 7 ± 2 µM; 10l EC50 42 ± 13 µM). Moreover, 10k reduces P. aeruginosa motility and biofilm formation, what is compatible with a quorum sensing related mechanism of action.

Synthesis and Antifungal Activity of Coumarins Derivatives Against Sporothrix spp.

Sporotrichosis is a serious public health problem in Brazil that affects human patients and domestic animals, mainly cats. Thus, the search for new antifungal agents is required also due to the emergence and to the lack of effective drugs available in the therapeutic arsenal. The aim of this study was to evaluate the in vitro antifungal profile of two synthetic series of coumarin derivatives against Sporothrix schenckii and Sporothrix brasiliensis. The three-components synthetic routes used for the preparation of coumarin derivatives have proved to be quite efficient and compounds 16 and 17 have been prepared in good yields. The inhibitory activity of nineteen synthetic coumarins derivatives 16a-i and 17a-j were evaluated against Sporothrix spp. yeasts and the most potent compounds were 16b and 17i. However, according to concentrations able to inhibit (minimum inhibitory concentrations) and kill (minimum fungicidal concentrations) the cells, 17i was more effective than 16b against Sporothrix spp. Thus, 17i exhibited good antifungal activity against S. brasiliensis and S. schenckii, suggesting that it is an important scaffold for the development of novel antifungal agents.

Identification of 1-Aryl-1H-1,2,3-triazoles as Potential New Antiretroviral Agents.

BACKGROUND: Low molecular weight 1-Aryl-1H-1,2,3-triazoles are endowed with various types of biological activities, such as against cancer, HIV and bacteria. Despite the existence of six different classes of antiretroviral drugs in clinical use, HIV/AIDS continue to be an on growing public health problem. OBJECTIVE: In the present study, we synthesized and evaluated thirty 1-Aryl-1H-1,2,3-triazoles against HIV replication. METHOD: The compounds were prepared by Huisgen 1,3-dipolar cycloaddition protocol catalyzed by Cu(I) between aryl azides and propargylic alcohol followed by further esterification and etherification from a nucleophilic substitution with acid chlorides or alkyl bromides in good yields. The compounds were submitted to the inhibition of HIV replication and evaluation of their cytotoxicity. Initially, the compounds were screened at 10 µM and the most active were further evaluated in order to obtain some pharmacological parameters. RESULTS: Thirty molecules were evaluated, six were selected - because they inhibited more than 80% HIV replication. We further showed that two of these compounds are 8-times more potent, and less cytotoxic, than nevirapine, an antiretroviral drug in clinical use. CONCLUSION: We identified very simple triazoles with promissing antiretroviral activities that led to the development of new drugs against AIDS.

Novel 1,2,3-triazole derivatives for use against Mycobacterium tuberculosis H37Rv (ATCC 27294) strain.

The purpose of this study was to prepare various 4-substituted N-phenyl-1,2,3-triazole derivatives using click chemistry. The derivatives were screened in vitro for antimicrobial activity against Mycobacterium tuberculosis strain H37Rv (ATCC 27294) using the Alamar Blue susceptibility test. The activity was expressed as the minimum inhibitory concentration (MIC) in µg/mL (µM). Derivatives of isoniazid (INH), (E)-N'-[(1-aryl)-1H-1,2,3-triazole-4-yl)methylene] isonicotinoyl hydrazides, exhibited significant activity with MIC values ranging from 2.5 to 0.62 µg/mL. In addition, they displayed low cytotoxicity against liver cells (hepatoma HepG2) and kidney cells (BGM), thereby providing a high therapeutic index. The results demonstrated the potential and importance of developing new INH derivatives to treat mycobacterial infections.