Spirooxadiazoline-oxindoles derived from imatinib show antimyeloproliferative potential in K562 cells.

Imatinib mesylate was the first representative BCR-ABL1 tyrosine kinase inhibitor (TKI) class for the treatment of chronic myeloid leukemia. Despite the revolution promoted by TKIs in the treatment of this pathology, a resistance mechanism occurs against all BCR-ABL1 inhibitors, necessitating a constant search for new therapeutic options. To develop new antimyeloproliferative substances, we applied a medicinal chemistry tool known as molecular hybridization to design 25 new substances. These compounds were synthesized and biologically evaluated against K562 cells, which express BCR-ABL1, a constitutively active tyrosine kinase enzyme, as well as in WSS-1 cells (healthy cells). The new compounds are conjugated hybrids that contain phenylamino-pyrimidine-pyridine (PAPP) and an isatin backbone, which are the main pharmacophoric fragments of imatinib and sunitinib, respectively. A spiro-oxindole nucleus was used as a linker because it occurs in many compounds with antimyeloproliferative activity. Compounds 2a, 2b, 3c, 4c, and 4e showed promise, as they inhibited cell viability by between 45% and 61% at a concentration of 10 µM. The CC50 of the most active substances was determined to be within 0.8-9.8 µM.

New azaaurone derivatives as potential multitarget agents in HIV-TB coinfection.

Tuberculosis (TB) disease, caused by Mycobacterium tuberculosis (Mtb) is the leading cause of death among people with human immunodeficiency virus (HIV) infection. No dual-target drug is currently being used to simultaneously treat both infections. This work aimed to obtain new multitarget HIV-TB agents, with the goal of optimizing treatments and preventing this coinfection. These compounds incorporate the structural features of azaaurones as anti-Mtb and zidovudine (AZT) as the antiretroviral moiety. The azaaurone scaffold displayed submicromolar activities against Mtb, and AZT is a potent antiretroviral drug. Six derivatives were synthetically generated, and five were evaluated against both infective agents. Evaluations of anti-HIV activity were carried out in HIV-1-infected MT-4 cells and on endogenous HIV-1 reverse transcriptase (RT) activity. The H37Rv strain was used for anti-Mtb assessments. Most compounds displayed potent antitubercular and moderate anti-HIV activity. (E)-12 exhibited a promising multitarget profile with an MIC90 of 2.82 µM and an IC50 of 1.98 µM in HIV-1-infected T lymphocyte cells, with an 84% inhibition of RT activity. Therefore, (E)-12 could be the first promising compound from a family of multitarget agents used to treat HIV-TB coinfection. In addition, the compound could offer a prototype for the development of new strategies in scientific research to treat this global health issue.

Novel 2-Nitroimidazole and Imidazooxazole Derivatives and their Activity against Trypanosoma cruzi and Mycobacterium tuberculosis.

BACKGROUND: Tuberculosis (TB) is one of the top ten causes of death worldwide, while Chagas disease (CD) is the parasitic disease that kills the largest number of people in the Americas. TB is the leading cause of death for patients with AIDS; it kills 1.5 million people and causes 10 million new cases every year. The lack of newly developed chemotherapeutic agents and insufficient access to health care services for a diagnosis increase the incidence of multidrug-resistant TB (MDRTB) cases. Although CD was identified in 1909, the chronic stages of the disease still lack adequate treatment. OBJECTIVE: The purpose of this work was to design and synthesize two new series of 2-nitroimidazole 5a-e and imidazooxazoles 6a-e with 1H-1,2,3-triazolil nucleus and evaluate their activities against Tc and Mycobacterium tuberculosis (Mtb). METHODS: Two series of five compounds were synthesized in a 3 or 4-step route in moderated yields, and their structures were confirmed by NMR spectral data analyses. The in vitro antitrypanosomal evaluation of products was carried out in an intracellular model using L929 cell line infected with trypomastigotes and amastigote forms of Tc of ß-galactosidase-transfected Tulahuen strain. Their antimycobacterial activity was evaluated against Mtb strain H37Rv. RESULTS: In general, 2-nitroimidazolic derivatives proved to be more potent in regard to antitrypanocidal and antimycobacterial activity. The non-cytotoxic 2-nitroimidazole derivative 5b was the most promising with a half maximum inhibitory concentration of 3.2 µM against Tc and a minimum inhibitory concentration of 65.3 µM against Mtb. CONCLUSION: Our study reinforced the importance of 2-nitroimidazole and 1H-1,2,3-triazole nuclei in antimicrobial activity. In addition, derivative 5b proved to be the most promising, presenting important activity against Tc and Mtb and could be used as a starting point for the development of new agents against these diseases.

Antimalarial and anti-inflammatory activities of new chloroquine and primaquine hybrids: Targeting the blockade of malaria parasite transmission.

Malaria is a disease that requires new drugs not only to fight Plasmodium but also to reduce symptoms of infection such as fever and inflammation. A series of 21 hybrid compounds were designed from chloroquine (CQ) and primaquine (PQ) linked to the pharmacophoric group present in phenylacetic anti-inflammatory drugs. These compounds were designed to have dual activity: namely, to be capable of killing Plasmodium and still act on the inflammatory process caused by malaria infection. The compounds were assayed with nine different biological methods. The carbonylated CQ derivative 6 (n = 3; R1 = Cl) was more potent than CQ in vitro, and 8 (n = 4; R1 = H) reduced P. berghei parasitemia up to 37% on day 7. The carbonylated PQ derivative 17 (R = Br) was slightly less potent than PQ. The gem-difluoro PQ derivative 20 (R = Cl) exhibited high transmission blockade of the malaria sporogonic cycle in mosquitoes. Compounds 6 and 20 dose-dependently reduced nitric oxide (NO) production and inhibited TNFα production by LPS-stimulated J774A.1 macrophages. Our results indicate a viable and interesting approach in planning new chemical entities that act as transmission-blocking drugs for treating malaria caused by P. falciparum and P. vivax and the anti-inflammatory process related to this disease.

Yellow fever virus is susceptible to sofosbuvir both in vitro and in vivo.

Yellow fever virus (YFV) is a member of the Flaviviridae family. In Brazil, yellow fever (YF) cases have increased dramatically in sylvatic areas neighboring urban zones in the last few years. Because of the high lethality rates associated with infection and absence of any antiviral treatments, it is essential to identify therapeutic options to respond to YFV outbreaks. Repurposing of clinically approved drugs represents the fastest alternative to discover antivirals for public health emergencies. Other Flaviviruses, such as Zika (ZIKV) and dengue (DENV) viruses, are susceptible to sofosbuvir, a clinically approved drug against hepatitis C virus (HCV). Our data showed that sofosbuvir docks onto YFV RNA polymerase using conserved amino acid residues for nucleotide binding. This drug inhibited the replication of both vaccine and wild-type strains of YFV on human hepatoma cells, with EC50 values around 5 µM. Sofosbuvir protected YFV-infected neonatal Swiss mice and adult type I interferon receptor knockout mice (A129-/-) from mortality and weight loss. Because of its safety profile in humans and significant antiviral effects in vitro and in mice, Sofosbuvir may represent a novel therapeutic option for the treatment of YF. Key-words: Yellow fever virus; Yellow fever, antiviral; sofosbuvir.

Beyond Members of the Flaviviridae Family, Sofosbuvir Also Inhibits Chikungunya Virus Replication.

Chikungunya virus (CHIKV) causes a febrile disease associated with chronic arthralgia, which may progress to neurological impairment. Chikungunya fever (CF) is an ongoing public health problem in tropical and subtropical regions of the world, where control of the CHIKV vector, Aedes mosquitos, has failed. As there is no vaccine or specific treatment for CHIKV, patients receive only palliative care to alleviate pain and arthralgia. Thus, drug repurposing is necessary to identify antivirals against CHIKV. CHIKV RNA polymerase is similar to the orthologue enzyme of other positive-sense RNA viruses, such as members of the Flaviviridae family. Among the Flaviviridae, not only is hepatitis C virus RNA polymerase susceptible to sofosbuvir, a clinically approved nucleotide analogue, but so is dengue, Zika, and yellow fever virus replication. Here, we found that sofosbuvir was three times more selective in inhibiting CHIKV production in human hepatoma cells than ribavirin, a pan-antiviral drug. Although CHIKV replication in human induced pluripotent stem cell-derived astrocytes was less susceptible to sofosbuvir than were hepatoma cells, sofosbuvir nevertheless impaired virus production and cell death in a multiplicity of infection-dependent manner. Sofosbuvir also exhibited antiviral activity in vivo by preventing CHIKV-induced paw edema in adult mice at a dose of 20 mg/kg of body weight/day and prevented mortality in a neonate mouse model at 40- and 80-mg/kg/day doses. Our data demonstrate that a prototypic alphavirus, CHIKV, is also susceptible to sofosbuvir. As sofosbuvir is a clinically approved drug, our findings could pave the way to it becoming a therapeutic option against CF.

New Efavirenz Derivatives and 1,2,3-Triazolyl-phosphonates as Inhibitors of Reverse Transcriptase of HIV-1.

BACKGROUND: According to the World Health Organization (WHO), the fight against Acquired Immunodeficiency Syndrome (AIDS) is still one of the most significant challenges facing humanity. Worldwide, it is estimated that 36.7 million people are infected by the Human Immunodeficiency Virus (HIV). Despite the variety of available drugs, the search for new enzymatic inhibitors of HIV is still important due to the presence of adverse effects and the development of resistant strains. Therefore, the present study aimed to design, synthesize, and biologically evaluate novel inhibitors of HIV Reverse Transcriptase (RT). MATERIALS AND METHODS: These compounds were obtained in two series, and compounds in both series contain a 1,2,3-triazole ring in their structures. The compounds in the first series are Efavirenz (EFV) analogues with the N-1 position substituted by another important fragment as described in the medicinal chemistry literature on anti-HIV drugs. The second series has a phosphonate chain similar to that in the structure of Tenofovir Disoproxil Fumarate (TDF). RESULTS AND CONCLUSION: The results of the biological evaluation showed that all compounds presented high RT inhibition values and lower or comparable inhibitory concentrations (the concentration needed to reduce the enzymatic activity by 50%, IC50 values, 0.8-1.9 µM). Among the compounds in the first series, the three with the lowest IC50 values had values between 0.8-0.9 µM, and of those in the second series, the most potent had an IC50 value of 1.1 µM; compounds in both series were equipotent to TDF (1.2 µM). Thus, the new compounds could be considered lead compounds for the development of new antiretroviral compounds.

The clinically approved antiviral drug sofosbuvir inhibits Zika virus replication.

Zika virus (ZIKV) is a member of the Flaviviridae family, along with other agents of clinical significance such as dengue (DENV) and hepatitis C (HCV) viruses. Since ZIKV causes neurological disorders during fetal development and in adulthood, antiviral drugs are necessary. Sofosbuvir is clinically approved for use against HCV and targets the protein that is most conserved among the members of the Flaviviridae family, the viral RNA polymerase. Indeed, we found that sofosbuvir inhibits ZIKV RNA polymerase, targeting conserved amino acid residues. Sofosbuvir inhibited ZIKV replication in different cellular systems, such as hepatoma (Huh-7) cells, neuroblastoma (SH-Sy5y) cells, neural stem cells (NSC) and brain organoids. In addition to the direct inhibition of the viral RNA polymerase, we observed that sofosbuvir also induced an increase in A-to-G mutations in the viral genome. Together, our data highlight a potential secondary use of sofosbuvir, an anti-HCV drug, against ZIKV.

New pentasubstituted pyrrole hybrid atorvastatin-quinoline derivatives with antiplasmodial activity.

Cerebral malaria is caused by Plasmodium falciparum. Atorvastatin (AVA) is a pentasubstituted pyrrole, which has been tested as an adjuvant in the treatment of cerebral malaria. Herein, a new class of hybrids of AVA and aminoquinolines (primaquine and chloroquine derivatives) has been synthesized. The quinolinic moiety was connected to the pentasubstituted pyrrole from AVA by a linker group (CH2)n=2-4 units. The activity of the compounds increased with the size of the carbons chain. Compound with n=4 and 7-chloroquinolinyl has displayed better activity (IC50=0.40 µM) than chloroquine. The primaquine derivative showed IC50=1.41 µM, being less toxic and more active than primaquine.

Efavirenz a nonnucleoside reverse transcriptase inhibitor of first-generation: Approaches based on its medicinal chemistry.

Acquired immunodeficiency syndrome (AIDS) is a disease caused by human immunodeficiency virus (HIV) that affects individuals on all continents. In 1987, the antiretroviral therapy began increasing survival rates and improving the quality of life for patients. Efavirenz (EFV) is a drug widely used in the treatment of HIV-AIDS since 1998. Belonging to a class of nonnucleoside reverse transcriptase inhibitors (NNRTI), it directly blocks the action of the enzyme and consequently the multiplication of the virus. Although EFV has provided excellent results in reducing viral load, cases of resistance associated with adverse effects have led to the search to find new analogs of this drug. Although many researchers are involved in this quest, curiously there is still no clinical substitute for EFV. To develop a second-generation version of EFV, it is essential understand the structure-activity relationships of the derivative compounds. Thus, the aims of the present review are to compare EFV and its derivatives using medicinal chemistry and to describe the main synthetic routes.

Novel selective inhibitor of Leishmania (Leishmania) amazonensis arginase.

Arginase is a glycosomal enzyme in Leishmania that is involved in polyamine and trypanothione biosynthesis. The central role of arginase in Leishmania (Leishmania) amazonensis was demonstrated by the generation of two mutants: one with an arginase lacking the glycosomal addressing signal and one in which the arginase-coding gene was knocked out. Both of these mutants exhibited decreased infectivity. Thus, arginase seems to be a potential drug target for Leishmania treatment. In an attempt to search for arginase inhibitors, 29 derivatives of the [1,2,4]triazolo[1,5-a]pyrimidine system were tested against Leishmania (Leishmania) amazonensis arginase in vitro. The [1,2,4]triazolo[1,5-a]pyrimidine scaffold containing R1  = CF3 exhibited greater activity against the arginase rather than when the substituent R1  = CH3 in the 2-position. The novel compound 2-(5-methyl-2-(trifluoromethyl)-[1,2,4]triazolo[1,5-a]pyrimidin-7-yl)hydrazinecarbothioamide (30) was the most potent, inhibiting arginase by a non-competitive mechanism, with the Ki and IC50 values for arginase inhibition estimated to be 17 ± 1 µm and 16.5 ± 0.5 µm, respectively. These results can guide the development of new drugs against leishmaniasis based on [1,2,4]triazolo[1,5-a]pyrimidine derivatives targeting the arginase enzyme.

Evaluation of genotoxic effects of new molecules with possible trypanocidal activity for Chagas disease treatment.

Chagas disease is responsible for a large number of human infections and many are also at risk of infection. There is no effective drug for Chagas disease treatment. The Institute of Pharmaceutical Technology at Fiocruz, Brazil, has designed three nitro analogs of the nitroimidazole-thiadiazole, megazol: two triazole analogs PTAL 05-02 and PAMT 09 and a pyrazole analog PTAL 04-09. A set of Salmonella enterica serovar Typhimurium strains were used in the bacterial reverse mutation test (Ames test) to determine the mutagenicity and cytotoxicity of megazol and its nitro analogs. Megazol presented positive mutagenic activity at very low concentration, either with or without metabolic activation S9 mix. The mutagenic response of the analogs was detected at higher concentration than the lowest megazol concentration to yield mutagenic activity showing that new advances can be made to develop new analogs. The micronucleus test with rat macrophage cells was used in the genotoxic evaluation. The analogs were capable of inducing micronucleus formation and showed cytotoxic effects. PTAL 04-09 structural modifications might be better suitable for the design of promising new drugs candidate for Chagas' disease treatment.

Fluorinated compounds against Mycobacterium tuberculosis.

Tuberculosis is a severe infectious disease currently being treated with drugs that were developed more than 40 years ago. In recent years, the emergence of resistant Mycobacterium tuberculosis strains, as well as co-infection with the AIDS virus, has caused global concern about the evolution of the disease. Thus, the search for new drugs has become a necessity and a great challenge. Fluorine is a strategic element that is very useful in medicinal chemistry for its great influence on the biological activity of substances. This review highlights the importance of fluorinated molecules that are currently in clinical use or pre-clinical phases of development. Further, some substances in the prototype development stage are cited, which potentially represent future alternatives for the treatment of tuberculosis.

New trifluoromethyl triazolopyrimidines as anti-Plasmodium falciparum agents.

According to the World Health Organization, half of the World's population, approximately 3.3 billion people, is at risk for developing malaria. Nearly 700,000 deaths each year are associated with the disease. Control of the disease in humans still relies on chemotherapy. Drug resistance is a limiting factor, and the search for new drugs is important. We have designed and synthesized new 2-(trifluoromethyl)[1,2,4]triazolo[1,5-a]pyrimidine derivatives based on bioisosteric replacement of functional groups on the anti-malarial compounds mefloquine and amodiaquine. This approach enabled us to investigate the impact of: (i) ring bioisosteric replacement; (ii) a CF3 group substituted at the 2-position of the [1,2,4]triazolo[1,5-a]pyrimidine scaffold and (iii) a range of amines as substituents at the 7-position of the of heterocyclic ring; on in vitro activity against Plasmodium falciparum. P. falciparum dihydroorotate dehydrogenase (PfDHODH) through strong hydrogen bonds. The presence of a trifluoromethyl group at the 2-position of the [1,2,4]triazolo[1,5-a]pyrimidine ring led to increased drug activity. Thirteen compounds were found to be active, with IC50 values ranging from 0.023 to 20 µM in the anti-HRP2 and hypoxanthine assays. The selectivity index (SI) of the most active derivatives 5, 8, 11 and 16 was found to vary from 1,003 to 18,478.

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.

[1-(3-Chloro-phen-yl)-1H-1,2,3-triazol-4-yl]methanol hemihydrate.

The asymmetric unit of the title hydrate, C(9)H(8)ClN(3)O·0.5H(2)O, comprises two independent 1,2,3-triazole mol-ecules and a water mol-ecule of crystallization. The dihedral angles between the six- and five-membered rings in the 1,2,3-triazole mol-ecules are 12.71 (19) and 17.3 (2)°. The most significant different between them is found in the relative orientations of the terminal CH(2)OH groups with one being close to perpendicular to the five-membered ring [N-C-C-O torsion angle = 82.2 (5)°], while in the other mol-ecule, a notable deviation from a perpendicular disposition is found [torsion angle = -60.3 (5)°]. Supra-molecular chains feature in the crystal packing sustained by O-H⋯(O,N) inter-actions along the a-axis direction. The chains are connected via C-H⋯N inter-actions and the resultant layers stack along the b axis.

Design, synthesis and pharmacological evaluation of HIV-1 reverse transcriptase inhibition of new indolin-2-ones.

The design, synthesis and anti HIV-1 replication inhibition of 3-(cyclopropylethynyl)-3-hydroxy-indolin-2-ones, analogues of efavirenz (Sustivatrade mark), are described. Different substituted isatins were used to generate final products that contain pharmacophoric features for RT inhibition, such as the oxoindole and cyclopropylethynyl groups. The suitability of the indolin-2-one ring in the planned compounds in replacement to the benzoxazinone ring of efavirenz was proven, since compound 15 presented a greater activity than efavirenz against HIV-1 replication and was not significantly cytotoxic.